Catalog of Meteorological Instruments 

in the 

Museum of History and Technology 
SMITHSONIAN STUDIES IN HISTORY AND TECHNOLOGY 

NUMBER 2 
Catalog of Meteorological Instruments 

in the 

Museum of History and Technology 

Prepared by 

W. E. Knowles Middleton 

SMITHSONIAN INSTITUTION^ PRESS 

CITY OF WASHINGTO^^ 1969 
For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price $3.25 

IV 
Contents 

Page 

Acknowledgments 3 

1. INTRODUCTION 3 

2. BAROMETERS AND BAROGRAPHS 7 

Invention of the Barometer 7 

Mercury Barometers and Barographs 8 

Aneroid Barometers and Barographs 23 

Other Instruments 33 

3. THERMOMETERS AND THERMOGRAPHS 37 

Early History 37 

Liquid-in-Glass Thermometers 38 

Maximum and Minimum Thermometers 45 

Bimetallic Thermometers 49 

Recording Thermometers 50 

Other Instruments 55 

4. INSTRUMENTS FOR THE MEASUREMENT OF ATMOSPHERIC HUMIDITY 61 

Absorption Hygrometers 61 

Condensation Hygrometers 64 

Psychrometers 66 

Other Instruments 70 

5. INSTRUMENTS FOR THE MEASUREMENT OF PRECIPITATION AND EVAPORATION 73 

Other Instrument 77 

6. INSTRUMENTS FOR MEASURING THE SURFACE WIND 79 

Wind Vanes and Wind-Direction Recorders 79 

Anemometers and Anemographs 82 

Other Instruments 89 

7. SUNSHINE RECORDERS 91 

Other Instrument 93 

8. NEPHOSCOPES 95 

9. UPPER-AIR INSTRUMENTS, NO T TELEMETERING 97 

Meteorographs for Use With Kites or Captive Balloons 98 

Meteorographs for Use With Free Balloons (Sounding Balloons) 99 

Meteorographs for Use on Aircraft 100 

Miscellaneous Apparatus Used in Connection With Upper-Air Observations 102 

10, RADIOSONDES 103 

Other Instruments 120 

11. MISCELLANEOUS METEOROLOGICAL INSTRUMENTS 123 

Combination Recording Instruments 123 

Other Instruments, Not Classified 124 

Bibliography 128 
Introduction 
^ 

[it' 

FIGURE 1 

Four barometers by Benjamin Pike & Sons, New York (MHT 316,739, MHT 

319,958, MHT 323,000, and MHT 326,144). (Smithsonian photo 61909.) 
Chapter 1 

Introduction 

In dealing with its collections of scientific instruments, generally assembled largely by chance, 

a great museum has to pay attention to its function as a means of public education, while 

meeting its obligation to provide materials for 

study by specialist scholars. Those who walk in 

the public galleries of such an institution and 

admire the skillfully arranged exhibits seldom 

have any idea of the mass of matericd, in depositories and storerooms, of which only a small 

sample can possibly be displayed. Were they to 

visit such a storeroom with its complexities of 

ordered disorder, they would probably be unable 

to make much of what they saw. Nor would they 

find what they saw very attractive; for, as every 

curator knows, old instruments coming to a 

museum nearly always need a good deal of expert 

refurbishing and restoring before they are fit to 

be put in an exhibition case; and unless they are 

to be exhibited, they do not receive it. 

The scholar is often obliged to do a good deal 

of mental restoration. This remark applies with 

particular force to meteorological instruments 

many of which in their years of service have 

necessarily been exposed to the weather. Indeed, 

this circumstance conditions the relative numbers of meteorological instruments of different 

types to be found in collections. In the European 

museums with which the writer is acquainted, 

the pattern is the same as in the Smithsonian 

Institution's Museum of History and Technology: 

the most numerous instruments are thermometers, which do not deteriorate much unless 

they are actually broken—though not many are 

very old—followed by aneroid barometers and 

barographs, which are generally kept indoors. 

Mercury barometers are often fairly common, 

and mercury barographs are frequently both 

numerous and well preserved, probably because 

even an unhistorically minded meteorologist 

would hesitate to break up such a complex and 

elegant piece of apparatus. But when it comes to 

things that went on poles, like anemometers, it 

is another story. Only a few are likely to have 

survived. 

The collection to which this catalog is devoted 

came to the Museum from many sources, but 

Acknowledgments 

Information regarding a number of instruments has been obtained from several people 

whose kindness is acknowledged in footnotes. 

Here, the writer must specially refer to the 

great assistance he received from Mr. Christos 

Harmantas of the U.S. Weather Bureau in the 

matter of radiosondes, on which Mr. Harmantas 

is a recognized authority. 
somewhat more than half of these instruments 

came from the principal centers of official 

meteorological observation in the United States. 

Federal government activity in relation to meteorology seems to date from 1819, when the office 

of the Surgeon General, U.S. Army, initiated 

systematic observation of the thermometer and 

wind vane at military posts. In 1855 the young 

Smithsonian Institution made meteorology one 

of its first concerns, distributing instruments 

around the country and correlating the observations which were reported via the recently 

developed telegraph network. In 1870 the Signal 

Corps, U.S. Army, took on the burden of official 

meteorology as a result of a joint resolution of 

the Congress and in accordance with Joseph 

Henry's dictum that the Smithsonian should not 

become the agency for such scientific work once 

its permanency had been decided upon. This did 

not terminate Smithsonian meteorology altogether, however, for at the end of the century 

the establishment of the Astrophysical Observatory by Henry's successor, S. P. Langley, reinvolved the Institution in observations related 

to solar physics. 

The decade of the 1860s marked the transformation of observational meteorology from a 

largely haphazard occupation of amateur observers, using simple instruments, into a more 

businesslike and systematic procedure pursued 

in permanent stations and using sophisticated 

instruments the results of which were automatically recorded or read at a distant point. In the 

1870s the Army Signal Corps acquired examples 

of most of the existing "systems," and installed 

them in a laboratory for the development of new 

types of instruments. Along with several European systems shown, there were two from American meteorologist-inventors—George Hough, Director of the Dudley Observatory, Albany, New 

York, and Daniel Draper, who had a private 

observatory in Central Park, New York City. 

In 1891 U.S. Government Meteorology moved 

again, this time to the Department of Agriculture, 

where it became a subordinate unit with the 

title U.S. Weather Bureau. In 1940 the unit was 

transferred to the Department of Commerce, and 

in 1966 it became the nucleus of a new bureau, 

the Environmental Sciences Administration. This 

unusually peripatetic history accounts for the 

miscellany of sources from which the instruments 

in this collection derive, for they represent the 

principal repository of the remains of official 

meteorology in the United States. 

The instruments in this Museum represent 

many donors, but the majority came from the 

American sources just mentioned. Our particular 

gratitude goes to Mr. Robert Wright of the U.S. 

Weather Bureau, who for many years has been 

alert to the history of his own field, and whose 

personal intervention has often prevented the 

discarding or cannibalization of important instruments which are now in the Museum of 

History and Technology. 

In the 19th century it was believed that 

"science" and "measurement" were almost 

synonymous terms. While this attitude has been 

modified, it remains true that the availability of 

suitable instruments has at all times been immensely important to the advance of science. 

Meteorology as a scientific discipline began 

immediately after the invention of the barometer, 

and as a result of it.i In more recent times our 

knowledge of weather processes has been enormously enlarged by the use of instruments for 

measuring temperature, humidity, surface wind, 

and other elements, and especially by the development and use of means of investigating the upper 

air. Therefore, the history of meteorological instruments is an important part of the story of 

the science of meteorology. 

The most ancient of these instruments is 

probably the wind vane for facilitating the observation of the direction of the wind. The rain 

gauge is also of a respectable antiquity. Next 

came the invention of a crude sort of hygroscope 

in the 15th century, and one type of anemometer 

was envisaged, if not built, at about the same 

1 See W. E. K. Middleton, A History oj the Theory oj 

Rain (London: Oldbovirne, 1965; New York: Franklin 

Watts, 1966), especially chapter 4, for evidence of this. 
time. The wonderful 17th century brought the 

barometer and thermometer, both carried to a 

useful degree of precision in the 18th century. 

The invention of the balloon in 1783 led at once 

to the investigation of the upper air, though more 

than a century had to elapse before the development of light instruments for unmanned balloons 

and kites made anything more than sporadic 

observations possible. Finally, in our own time, 

the progress of electrical engineering, giving us 

the radiosonde and radar, has .made upper-air 

observations a regular part of the data furnished 

every day to the forecaster. 

This catalog contains a short summary of the 

history of each type of instrument, accompanied 

by descriptions of the more interesting or important specimens in the collection, introduced 

at appropriate places, but set apart typographically so that the narrative can easily be read 

through by itself if the reader prefers to do this. 

At the end of each chapter will be found a list of 

the other instruments in the Museum that have 

not been discussed in the text. While most of the 

instruments described are in the collections of the 

Museum of History and Technology (MHT), a 

few are in the collections of the National Air and 

Space Museum (NASM). The Museum of History and Technology is naturally rich in apparatus of American origin, and an attempt has been 

made to cover such specimens in some dejtail 

without overemphasizing their importance in the 

history of meteorological instrumentation. It is 

thought that the typographical arrangement will 

contribute to this end. 
FIGURE 2 

Berti's experiment. (Plate 12 from Technica curiosa, sive mirabilia artis by Caspar 

Schott, 1687, opposite page 203; Smithsonian photo 60824.) 
Chapter 2 

Barometers and Barographs 

Invention of the Barometer 

The barometer, which lies at the very foundations of meteorology, is also an instrument of 

great philosophical importance, for its invention, 

and the experiments made with it, finally disposed of the long-cherished dogma of the impossibility of a vacuum. At the beginning of the 

17th century several people, notably Isaac 

Beeckman and Galileo Galilei, were sure that a 

vacuum could exist, though Galileo, strangely 

enough, never believed in the pressure of the 

air. 2 The great French philosopher Rene Descartes, on the other hand, made up his mind that 

all space must be filled with something, so that 

a vacuum is quite impossible; and Descartes, as 

is well known, seldom let his mind be changed 

by experiments. 

Experiments began to be performed, especially 

in Italy. The first that is of concern to us here 

was done in Rome by Gasparo Berti (d. 1643) 

sometime after 1639, and probably before 1642. 

Berti, watched by a number of people interested 

in "natural philosophy," fastened a lead tube to 

the wall of his house, with a glass flask at the top. 

provided with a screw plug. The bottom of the 

tube, which had a stopcock on it, was under 

the water in a cask that stood on the ground 

(figure 2). This stopcock was first closed, and 

the tube and flask completely filled with water 

from the top. The plug was then replaced; and 

when the stopcock was opened, the water went 

out of the flask, leaving an apparendy empty 

space. The stopcock was then closed again and 

the plug loosened, whereupon the air rushed 

into the flask "with a loud noise," demonstrating 

that the flask had been empty. A sounding line 

showed that the water in the tube was 18 cubits 

(about 10 meters) above the level in the cask.^ 

Berti was trying only to find out whether a 

vacuum could be produced, and cannot be 

credited with the invention of the barometer. 

Indeed, the pressure of the air was not even 

adduced as an explanation of the suspension 

of the column of water in the pipe. The conscious 

invention of the instrument that became the 

barometer must be ascribed to Evangelista 

Torricelli (1608-1647). His part in the story is 

2 For more details, see W. E. K. Middleton, The History 

oj the Barometer (Baltimore: Johns Hopkins Press, 1964). 

^ The full account by Emmanuel Maignan (1601-1676) 

from his Cursus philosophicus .. . (4 vols, paged as one, 

Toulouse, 1653), pp. 1925-36; for translation, see ibid., 

pp. 10-15. 
known solely from three letters exchanged between Torricelli and Michelangelo Ricci (1619-

1692), and dated 11, 18, and 28 June 1644.'^ 

Torricelli's first letter describes the famous experiment made by his young student Viviani 

in which tubes full of mercury were inverted in a 

dish of that liquid, whereupon the mercury in 

the tubes fell to about 75 cm above the level 

in the dish. Torricelli ascribed this suspension 

to the weight of the air; and in his letter of 

28 June, in answer to Ricci's questions, showed 

that he realized that the air was elastic as well 

as heavy. 

It is not known whether Torricelli and Viviani 

ever applied a scale to their tube—in fact there 

is no evidence of Torricelli's further interest in 

the barometer after 1644—but he had announced 

in his first letter that he was trying "to make 

an instrument to show the changes of the air," 

and for this reason the invention of the barometer 

is rightiy credited to Torricelli. The first use of 

a scale that we know about is due to Descartes, 

who on 13 December 1647, drew two similar 

scales on paper and sent one to Marin Mersenne, so that they might make comparable 

observations.6 

Mercury Barometers and Barographs 

The earliest technical improvement on the 

Torricellian tube was the siphon barometer, 

invented by the French mathematician and 

mystic Blaise Pascal (1623-1662) before about 

1650.® The siphon barometer, which appears 

as one of the three instruments in MH T 319,794,^ 

had some slight advantages in portability over 

* First printed by Carlo Dati in his Lettere a Filaleti di 

Timauro Antiate . . . (Florence, 1663); the second, from 

Ricci, only in part. They are in Torricelli, Opere, eds. 

G. Loria and G. Vassura. (Faenza, 1919) vol. 3, pp. 

186-88, 193-95, 198-201. 

* Descartes, Oeuvres, eds. Charles Adam and Paul Tannery 

(Paris, 1897-1913), vol. 5, p. 99. 

* Pascal, Traictez de I'equilibre des liqueurs et de la pesanteur 

de la masse de Pair . . . (Paris, 1663), p. 100. 

7 See p. 10. 

FIGURE 3 

MHT 316,857. Hooke's wheel barometer. A 

reproduction marked "L. C. Eichner fecit anno 

MCMLIX" of the version described in the 

Micrographia. It is mounted on a wooden frame 

96 cm high. The bulb at the top is 18 cm in 

diameter and the brass scale is 53 cm in diameter. 

(Smithsonian photo 61903.) 

the Torricellian tube, but to an age quite unaccustomed to fine measurements, the diminution of the movement of the upper mercury 

surface because of that of the lower one was a 

serious disadvantage. In fact, the history of the 

barometer for the rest of the 17 th century is 

largely a record of attempts to expand the scale 

of the instrument to make it easier to read. 

It should be noted that this would not necessarily increase the real accuracy of reading. 

One of the earliest and eventually the most 

popular of these expanded-scale barometers was 

the "wheel barometer" invented, probably in 

December 1663, by Robert Hooke (1635-1703,) 

8 
"curator of experiments" to the newly formed 

Royal Society. The Museum possesses a replica 

constructed according to Hooke's engraving 

(figure 3).^ It will be seen from the figure that 

this is a large siphon barometer with a float in 

the shorter limb. This float is attached to a thread 

which passes over a pulley, on the shaft of which 

is a pointer moving over a scale. A small weight 

partly counterpoises the float. The upper surface 

of the mercury was at the diametral plane of the 

large bulb, in order to throw nearly all the motion of the mercury into the short limb; but later ^ 

Hooke realized that this was not important, and 

lengthened the tube to allow more room for any 

air that might remain in the tube, altering the 

diameter of the pulley accordingly. 

Thousands of wheel barometers were made, 

especially in decorated cases of "banjo" shape 

for household use. The Museum has a 19thcentury example (MHT 308,173). 

MHT 308,173. Household wheel barometer, 

showing from top to bottom a hygrometer 

(twisted gut), a spirit thermometer, a convex 

mirror, the barometer dial graduated from 28 

to 31 inches in hundredths, and a bubble level 

surrounded by a plate carrying the legend 

"D. Fagioli & Son 39 Warner S\ Clerkenwell." 

Overall length 96 cm, extreme width 26 cm. 

Presented by Taylor Instrument Companies, 

Rochester, N.Y. 

Hooke himself incorporated a barograph in his 

famous meteorograph or "weather clock," *° and 

it was probably an adaptation of the wheel barometer. Many barographs since then have operated on the same principle, ^^ and the Museum 

has a specimen of a recent and successful one 

(MHT 316,500, figure 4), designed about 1904 

by C. F. Marvin of the U.S. Weather Bureau.^^ 

Hooke knew that friction and dirtying of the 

mercury would limit the usefulness of such barometers and cast about for another means of 

MHT 316,500. Marvin's compensated barograph, 1904. A siphon barometer with a tube 

3.8 cm in diameter has a float in the short leg. 

A cord from the float passes over a pulley to a 

counterweight. The pen is supported from a 

larger pulley on the same shaft, so that the 

pressure changes are magnified five times on the 

drum, which is 13.5 cm in diameter and 28 cm 

long. The chart is graduated from 28.80 to 

30.80 inches. The clock that drives the drum has 

a handsome dial. The baseplate is marked 

"Compensated Barograph N° 1 Marvin 

System Made by Schneider Brothers, N.Y." 

This instrument is compensated for changes of 

the ambient temperature by designing the 

tube so that it will have the proper volume of 

mercury in it. This possibility was mentioned 

by various people, first, probably, by G. W. 

Hough in Annals of the Dudley Observatory, 

Albany. N.Y., volume 1 (1866), pages 88-90. 

There is a glazed case for this barograph, 216 

cm high and 46 cm wide x 33 cm deep. Transferred from the Weather Bureau in 1959 

(Smithsonian photo 46740-E.) 

* Hooke, Micrographia . . . (London, 1665), plate 1. 

•" Phil. Trans., vol. I (1666), pp. 218-19. 

" W. E. K. Middleton, Physis, vol. 3 (1961), pp. 213-22. 

" Op. cit. (footnote 2), pp. 287-97. 

'2 C. F. Marvin, U.S. Monthly Weather Review, vol. 36 

(1908), pp. 307 and 313. 
MHT 319,794. Barometer, "Controleur," and 

thermometer. A wooden frame 28 x 98 cm 

decorated with marquetry, enclosing a paper 

panel on which are mounted three separate 

instruments: a Reaumur thermometer, a simple 

siphon barometer, and a "Controleur," i.e., a 

two-hquid barometer of Hooke's type. This last 

has a scale divided into 32 divisions, with words 

from "Tres sec" to "Tempete" at each fourth 

division. The front of the instrument is glazed. 

The dates of various record temperatures, the 

latest 1812, are given near the thermometer. 

Marked "Controleur et Thermometre selon 

Reaumur Par Le-Secq, de La Gorgue, Department Du Nord." Received in 1961. (Smithsonian 

photo 61903-A). 

expanding the scale, arriving first at the socalled "double barometer" or two-liquid barometer which he demonstrated to the Royal 

Society in 1668.*^ The cylindrical bulbs are long 

enough to accommodate pressure changes, and 

the reading is taken from the water surface.. This 

barometer shows changes of piessure very well, 

but suffers from evaporation, and it became very 

common to mount one of these instruments and 

a siphon barometer on the same board, often 

with a large thermometer, as in the example 

(MHT 319,794) shown in figure 5, which dates 

from about 1815. The double barometer in this 

combination came to be called a "Controleur," 

"ControUeur," or "ContraroUeur," for reasons 

which are not quite certain, 

Hooke also invented ^* a barometer using three 

liquids—mercury, alcohol, and turpentine— 

which could give any magnification desired. 

Another means of expanding the sczde of a 

barometer was to hang either the Torricellian 

tube or its cistern from one arm of a balance. 

Marin Mersenne (1588-1648) had weighed the 

" Thomas Birch, History oj the Royal Society (London, 

1756-57), vol. 2, p. 298. 

1^ Phil. Trans., vol. 16 (1686), pp. 241-44. The invention 

of both these barometers has been claimed for others. See 

also op. cit. (footnote 2), chapter 6. 

10 
FIGURE 6 

MHT 316,941. Draper's balance barograph. by clockwork. Height 76 cm, width 70 cm. This 

The cistern is hung on springs and is connected one was used for many years at the Lick Obto the recording pen. As the mercury falls from servatory, and was presented by the University 

the tube into the cistern, the pen is deflected of California in 1960. (Smithsonian photo 

downward. The flat chart is moved horizontally 46751.) 

u 29,9-340 O—69-
tube in this way by 1647,^^ but it was not until 

about 1679 that Sir Samuel Morland used this 

scheme to make a barometer.^^ Such barometers 

never became popular, but the principle of 

weighing was used in several elaborate barographs towards the end of the 19th century, and 

the Museum possesses one (MHT 316,941, 

figure 6) designed by Daniel Draper of New 

York about 1884.^'^ This one was used at the 

Lick Observatory in California. ^^ 

Sir Samuel Morland,^^ and apparently also 

Bernardo Ramazzini of Modena,^° invented 

another sort of instrument known as the diagonal 

barometer, in which the top of the tube is bent 

through nearly a right angle, so that a small rise 

in the column of mercury corresponds to a much 

larger distance along the sloping tube. Such 

instruments became popular as household 

weatherglasses, especially in England, and their 

peculiar shape was sometimes taken advantage 

of in combining them with a thermometer and 

mounting them with a mirror or, as in the 

example in the Museum's collections (MHT 

319,469), with an engraving as shown in figure 7, 

Various other methods of expanding the scale 

of the barometer have been devised during the 

last three centuries, none of which are represented in the collections.^^ 

A barometer, in the form of a Torricellian 

tube, was first carried up a mountain by Florin 

Perier on 19 September 1648,^^ and the results 

15 Mersenne, Novarum observationum physico-maihematicarum 

Tomus III (Paris, 1647), first preface. 

i« See W. E. K. Middleton, Notes & Records Royal Society 

oj London, vol. 20 (1965), p. 150. 

" Draper, American Meteorological Journal, vol. 1 (1884-5), 

pp. 332-34. 

1* See Publications oj the Lick Observatory, vol. 1 (1887), 

pp. 78-79. 

19 John Smith, A Compleat Discourse oj . .the Baroscope 

or Quicksilver Weather Glass (London, 1688), pp. 1-2. 

2" Ramazzini, Ephemerides barometricae mutinenses anni 

M. DC. XCIV . . (Modena, 1695), pp. viii-ix. 

21 See Middleton, op. cit. (footnote 2), chapter 6. 

22 Pascal, Recit de la grande experience de fequilibre des 

liqueurs . . . (Paris, 1648). 

convinced most people of the pressure of the air. 

But Perier had to set up the Torricellian experiment afresh at the top of the mountain. Later, 

the desire of travelers for portable barometers 

had a great influence on the design of these instruments. It is impossible to deal with all the 

devices that were used to make barometers 

easier to transport, but most of them fall into 

two groups: special constructions of the cistern, 

and improved versions of the siphon barometer. 

As early as 1688 it was discovered that various 

kinds of hardwood—especially boxwood—are 

impervious to mercury but will permit the passage 

of air, at least along the grain; and for two 

centuries boxwood formed a part of the cisterns 

of most portable barometers, allowing them to be 

otherwise closed. Some of these cisterns had 

leather bottoms, with a screw plunger for adjustment, but such barometers were most probably 

intended for installation in a house at some distance from where they were made—they were 

transportable rather than portable. The Museum 

possesses an example, not quite complete (MHT 

326,225). 

MHT 326,225. Barometer inscribed "J^. Bon 

& C°. Dundee." This is a fixed-cistern barometer with the cistern enclosed in a brass box, the 

tube in a rectangular mahogany case. Near the 

top of the case a door, with a Fahrenheit thermometer mounted on the back of it, covers a 

V-shaped recess of which the scale of the barometer forms the walls. The actual cistern is of 

boxwood with a leather bottom; a plunger for 

adjusting this is evidently missing. The scale is 

in tenths of an inch from 27.5 to 31.4. No vernier, but a simple pointer operated by a rack 

and pinion, the knob being lost. Overall length, 

95 cm. Presented by Miss Elsie Howland Quinby, Washington, D.C. 

A different way of adjusting the amount of 

mercury in the barometer, or of filling the cistern 

for transport, was by overflow, providing a 

plugged hole at an appropriate height on the 

cistern. If the barometer was laid flat 2ind the 

plug removed, the cistern could be filled; then 

if it was placed erect, mercury would run out 

12 
FIGURE 7 

MHT 319,469. Diagonal barometer, thermometer, and hygrometer, late 18th century, by 

Watkins, London. A mahogany frame, 69 x 89 

cm, decorated with typical 18th-century stringing and gilt carvings; three gilt brass urns at the 

top. Running up the left side and across the top 

is a diagonal barometer. The scale is graduated 

from 28 to 31 inches, with a magnification of 

about six. There is an index that moves along a 

slot and can be set by hand. On the right side of 

the frame is a thermometer with a spherical bulb 

and a brass scale in Fahrenheit degrees, also 

with a setting pointer. Centered above the engraved perpetual calendar is a catgut hygrometer about 5 cm in diameter. It is interesting 

that a rather similar instrument in the Science 

Museum, London, has a copy of this same engraving. (Smithsonian photo 61910-D.) 

13 
until it was level with the lower edge of the hole. 

M H T 327,568 shows this feature. 

MHT 327,568. Late-18th-century barometer 

almost entirely enclosed in a mahogany box 

93 X 4.5 x 3.6 cm, with a very slender spirit 

thermometer 28 cm long, 10° to 212° F, on the 

front. The cistern is of wood with a screwed plug 

near the top. The scales of this and of the barometer (27 to 31 inches in tenths) are on boxwood inlays. A simple pointer, no vernier, the 

pointer on a small wooden block slid along a 

groove by hand. Inscribed "Brook Fecit Norwich." Received in 1966. 

Anothe r possibility for makin g the baromete r 

portabl e is to divide the cistern into two volumes 

so proportioned tha t whe n the tub e is quite full 

of mercury (having been inclined) the mercur y 

just fills the lower compartment, which is then 

shut off from the uppe r one. This idea was 

Lavoisier's, according to Louis Cotte;^^ an d 

Joh n Frederick Newma n used the idea with 

grea t success in the 1830s.2* I n 1860 L. Woodruff 

of An n Arbor, Michigan, was awarde d U.S . 

Paten t 28,626 for such a cistern, an d his barometer (MH T 314,608) is in the collection. 

M HT 314,608. Mercury barometer patented 

by L. Woodruff. This has an iron cistern with 

a removable screw plug between upper and 

lower chambers. There is a scale in tenths of 

an inch graduated from 27 to 31 inches, and 

a vernier reading to 0.01 inch. The attached 

thermometer is in degrees F. The instrument is 

94 cm long. The scale is inscribed "Charles 

Wilder Peterboro, N.H. Woodruff''s Pat. June 5, 

1860." Gift of Mrs. Hallie Stephens Caine, 

North Bend, Ohio. 

Anothe r sort of portable barometer, favored by 

mountaineers during the early 19th century, 

was the improved siphon barometer, with the 

internal diamete r of both legs of the U-tube the 

same. This was characteristically mad e portabl e 

by means of a tap nea r the bend, as in the 

ingenious instrument of J. A. Deluc, designed 

M H T 325,753. Marine barometer, 

inscribed "Spencer Browning & C°. 

Minories London." This has a mahogany case with a cistern-cover of 

brass. The actual cistern is of boxwood with a leather bottom; a 

plunger operated by a thumbscrew 

and permitting a little adjustment 

is concealed when the base of the 

cover is screwed on. The scale is 

graduated on ivory, 26.3 to 31 inches 

in tenths, with a vernier to 0.01 

inch, but no index. Thermometer 

in °F + °R. Mounted in gimbals 

on a strong brass bracket. Overall 

length 92 cm. Received in 1964. 

(Smithsonian photo 61908-A.) 

in the 1750s.^^ Anothe r form, bu t withou t the 

tap, was devised by the famous chemist Joseph 

Louis Gay-Lussac (1778-1850) ;26 this was mad e 

so tha t it could safely be carried upside down . 

T h e readings of the two scales ar e adde d or 

subtracted, according to their arrangement. 

T h e advantag e claimed for the siphon baromete r 

was tha t the capillary depression of the mercury 

surfaces could be neglected, because the tubes 

wer e of the same bore . It was no t realized tha t 

it migh t be different for the surface in a vacuum 

a n d tha t exposed to the air. Nevertheless, the 

accuracy of the best siphon barometers was 

probably greater tha n tha t of simple cistern 

barometers such as those described so far. 

Barometers for marin e use presented a special 

problem, because the motion of th e ship caused 

23 Traite de Meteorologie (Paris, 1774), vol. 1, p. 516-

2* See also pp. 19-20. 

25 Deluc, Recherches sur les modijcations de Vatmosphere . . . 

(Geneva, 1772), vol. 1, 64 ff. There was also an octavo 

edition (Paris, 1784). 

26 Gay-Lussac, Ann. Chim. et Phys., vol. 1 (1816), pp. 

113-19. 

14 
large oscillations of the mercury surface. The way 

of remedying this is to have a constriction in 

the tube, and this was first suggested by Robert 

Hooke on 2 January 1667/8 27 and reinvented 

by Edward Nairne more than a century later,28 

in the form of a length of capillary tubing near 

the middle of the barometer tube. The Museum 

has a typical marine barometer of the 1830s 

(MHT 325,753, figure 8). 

As the need for accuracy became more pressing 

after about 1770, it was recognized that better 

means must be devised to measure the position 

of the upper mercury surface, and to bring the 

lower surface precisely to the zero of the scale. 

As to the upper surface, there was much argument about whether the top or the edge of the 

meniscus should be read, most simple barometers 

of the 18th century having indexes that would 

serve only for the latter alternative. The change 

to reading the top of the meniscus took place in 

England about 1775, when the famous instrument 

maker Jesse .Ramsden (1735-1800) hit upon the 

idea of surrounding the barometer tube with a 

wide ring of somewhat greater diameter, having 

a plane lower surface, and making provision for 

illumination from the back, so that the plane of 

the bottom of the ring could be set tangent to the 

meniscus. When, towards 1800, it became common to use a brass tube 2 or 3 cm in diameter as 

the frame of the barometer, it was easy to cut 

slots front and back and to divide the vernier on 

a piece of the same tube cut to slide in the front 

slot. This construction may be seen in almost all 

the later 19th- and 20th-century barometers in the 

Museum {e.g., MH T 314,712) .^^ Ramsden's invention increased the precision of reading the 

upper surface by about tenfold. 

Ramsden also seems to have made a contribution to the setting of the zero by providing a littie 

ivory float in the cistern, but it was necessary 

to take out a plug and look into the cistern in 

C A 'I' A L C) G U E 

or 

MATHEMATICA L AND OVTfOA L 

INSTRUMENTS, 

p[)ilo0opl)ical ani> c!ll)emical apparatus, 

CONST R i; C T I: D AN D SOL O 

JA.nE * «-»tKEi\, 

N C). 13 SOUT H S T R V. i: T, 

m A I T I MOKE., 

j\'o. I 7 .u MS Me o ^tn II'.11" , 

NEW YORK. 

FIGURE 9 

Cover of James Green's first New York catalog. 

(Smithsonian photo 60765.) 

order to see it. Others, notably Antoine AssierPerica, produced other designs with floats; ^° and 

introduced the use of cisterns constructed partiy 

of glass, so that the mercury could be seen. An 

interesting one is due to Horner, apparentiy 

dating from just before 1800,^^ in which the glass 

tube not only reveals the level of the mercury, 

but acts as a cylinder in which a rather complicated piston can be moved up and down in order 

" Royal Society, Classijied Papers XX, item 48. Autograph. 

28 G. J. Phipps, A Voyage Towards The North Pole Undertaken by His Majesty's Command (London, 1773), pp. 123-24. 

29 See p. 18. 

"o Op. cit. (footnote 2), pp. 208-10. 

»i Gehler, Physikalisches Worterbuch (Leipzig, 1825^5) 

vol. 1, pp. 784-85 and figures 154 and 155. 

15 
to adjust the level. The outer brass tube has 

windows front and back, extending a littie above 

the edge of the top cap. It is to this edge that the 

mercury level is adjusted. 

Our present interest in Horner's barometer is 

that its method of observing the level of the 

mercury was adopted, or possibly re-invented, by 

James Green, the flrst important maker of meteorological instruments in the United States. This 

excellent instrument maker established a business 

in Baltimore in 1832, and moved to New York in 

1849, issuing a catalog, the wrapper of which is 

reproduced in figure 9.^^ The firm name was 

changed in 1885 to "Henry J. Green"; Henry J. 

was James's nephew, and he later moved to 

Brooklyn, which was uniformly spelled "B'klyn" 

on all his instruments that this writer has 

examined. 

James Green's first design of a portable barometer was exactiy like Horner's in its way of 

establishing the zero of the scale, but the volume 

of the cistern was adjusted by deforming a leather 

bag by means of a plunger operated by a thumbscrew. The Smithsonian Institution bought some 

for distribution, and the Museum has one of 

these (MHT 224,424, figure 10) in its collections. 

This is probably the sort of instrument referred to 

by Joseph Henry in the Report of the Commissioner 

of Patents for the Tear 1855.^^ 

A much better construction for a portable 

cisern barometer had been developed in France 

by the important instrument maker Nicolas 

Fortin, who made a happy combination of the 

glass-walled cistern, the ivory point, and the 

leather bag. His original design, described in 

1809 by J. N. P. Hachette,^* is an excellentiy 

conceived structure of brass, glass, and boxwood. 

'2 The date 1844 is a misprint; the verso of the v^apper 

contains a notice dated "Nevi^ York, 1849." The tide page 

makes it plain that this must have been a reissue of an 

earlier catalog first issued at Baltimore, probably in 1844. 

33 Washington, D.C, 1856, vol. 1, p. 370. 

3* Programmes d'un cours de physique . . . (Paris, 1809), 

pp. 221-25. 

FIGURE 10 

MHT 224,424. James Green's 

earlier portable barometer, 

marked "Smithsonian Inst" Ja^ 

Green" and (in much larger 

and more deeply engraved letters) "N.Y.," which may possibly indicate that it was under 

construction when the move 

was made in 1849. Length 

94 cm; the brass frame 2.5 cm 

in diameter; the cistern 5.0 cm 

in diameter and 5.7 cm long. 

The scale is graduated in tenths 

of an inch from 24.8 to 32 

inches, and the vernier reads 

to 0.01 inch. (Smithsonian 

photo 61910-A.) 

FIGURE 11 

MHT314, 625. Fortin barometer for mountain use, inscribed on the mounting of 

the attached thermometer 

"Ernst, Rue de Lille, N» 11, 

a Paris (N° 303)." Scale in 

millimeters from 400 to 825. 

Vernier to tenths, mounted 

on a friction-tight slide with 

a small knob, to be moved 

directly by hand. Protective 

brass tube only 1.4 cm in 

diameter. Glass cylinder of 

cistern 4.0 cm in diameter. 

Cistern and its outer case 11.5 

cm long. Overall length 100 

cm. Thermometer graduated 

from —24 to +52° G. Provenance unrecorded. (Smithsonian 

photo 61910-C.) 

FIGURE 

10 

FIGURE 

11 

16 
FIGURE 12 

James Green's Fortintype barometer. (U.S. 

Weather Bureau Circular 

F, 1894, page 7; Smithsonian photo 63883.) 

which has been copied, with variations, by almost 

every maker of meteorological instruments from 

that day to this, usually under the name of 

"Fortin barometer." In fact, there is a tendency—even in some museum catalogs—to call 

any barometer in which the mercury is set to a 

point a "Fortin barometer." As we shadl see, this 

is quite unjustifiable. 

This Museum has a very beautiful example of 

this construction (MHT 314,625, figure 11), 

intended for mountain use and made by Ernst 

of Paris. The very long range of the scale and the 

extreme slenderness of the protecting tube are 

to be noted. 

Probably the best and most durable design of 

Fortin-type barometer ever made is the celebrated instrument of James Green, first described 

in 1856 ^* and supplied by him and his successors 

for almost a century, first to the Smithsonian 

Institution and later to the Signal Service of the 

United States Army, and to the Weather Bureau. 

The distinguishing characteristic of this design 

is the entire absence of glue or cement of any 

kind, and the avoidance of screw thrjeads cut in 

boxwood. The construction of the instrument 

will be clear from figure 12,'* witii the remark 

that the two boxwood parts of the cistern, i and 

j , are held together by the two split rings L 

and M, and can be separated by removing one 

screw and loosening three others. If Fortin-type 

3* Smithsonian Institution, lOth Annual Report (Washington 1856), pp. 251-58. 

36 From U.S. Department of Agriculture, Weather 

Bureau, Barometers and the Measurement oj Atmospheric Pressure ... . Circular F. Instrument Room (Washington, 

1894). There have been numerous later editions. 

17 
-•%. 

FIGURE 13 

MHT 314,942. Green's Fortin-type 

barometer, large model with tube about 

12 mm bore and cistern about 60 mm. 

Total length 110 cm. The scale is 

graduated in 20ths from 25.5 to 32.6 

inches, with a vernier to 0.002 inch, 

and in mm from 648 to 832, with a 

vernier to 0.05 mm. The thermometer 

is graduated in °F and °C on the tube, 

numbered on the frame, originally 

silvered. Cistern cover inscribed "Henry 

J. Green New York." This barometer, 

which dates from about 1890, was 

transferred from the Smithsonian Astrophysical Observatory in 1956. It is still 

in working order. (Smithsonian photo 

61908.) 

barometers are to be useful, the cisterns must be 

cleaned from time to time, and the great merit 

of James Green's design is that it makes this 

possible with littie risk. The specimen (MH T 

314,942, figure 13) in the Museum is a large 

example "after the English model," ^'^ that is to 

say with the scale and vernier enclosed in a glass 

tube, a practice introduced by the instrument 

maker Patrick Adie about 1855, and still current. 

In spite of the great durability of this construction, some people continued to distrust the 

leather bag, and at some time in the 1880s an 

adjustable cistern without one was designed by 

Charles B. Tuch of the Weather Bureau.^* 

Like Horner, Tuch used a piston. The Museum 

has one of these barometers (MHT 314,712; 

see diagram, figure 14). 

MHT 314,712. Barometer with the cistern designed by Charles B. Tuch, marked "H. J. 

Green B'klyn. N.Y." and also "Signal Service 

N°. 160 A." It is 104 cm long overall, and the 

blackened brass tube that forms its frame is 

2.1 cm in diameter. The scale is in tenths of 

inches from 26 to 33 inches, with a vernier 

reading to 0.01 inch. The attached thermometer 

is graduated from —20 to +125°F. Transferred 

from the Weather Bureau in 1955. (Smithsonian photo 61902-D.) 

Of the other designs of an adjustable cistern 

in which the mercury is raised to touch a fiducial point, only two need be mentioned. 

The first is represented by MH T 325,999, and a 

cross section of the cistern is shown in figure 15, 

from which it will be seen that there is provision 

for closing the end of the tube for transport. 

MHT 325,999. Mercury barometer, marked 

"Tycos Taylor Instrument Companies Rochester 

N.Y. N°- 2179." This is a laboratory or station 

barometer with a cistern having a glass tube A, 

4 cm in diameter, through which an ivory point 

G may be seen. The cistern proper forms a 

sub-assembly which can be moved up and down 

37 Catalog of Henry J. Green, 771 Broadway, New York, 

1887, p. 14. It was a "Standard Observatory Barometer," 

and cost S60. 

38 Op. cit. (footnote 36), p. 11. 

18 
by turning the screw F, in order to adjust the 

surface of the mercury to G. For transport, after 

inclining the instrument, the tube can be closed 

by the pad on the bottom of the cistern. The 

barometer is graduated from 650 to 825 mm 

and from 25.5 to 32.5 inches, with verniers 

reading to 0.1 mm and 0.001 inch respectively. 

There is an attached thermometer graduated 

in half degrees from —17 to 4-50° C. Overall 

length, 96 cm. Wooden case with lock. Provenance unrecorded. 

The second (MHT 316,421) is ingeniously 

designed so that—apart from the point itself, 

and a gasket—the entire cistern can be molded 

from plastic materials in two parts.^^ It was 

intended as an instrument of moderate accuracy 

for schools. 

MHT 316,421. Mercury barometer marked 

"Central Scientific Co. U.S. Patent Nos. 

1,353,482 and 1,632,084." The tube is enclosed 

in a light metal tube of hexagonal cross section; 

the cistern is of plastic material in two parts. 

The scale, on an attached flat plate, is graduated from 620 to 814 mm, with a vernier reading to 0.1 mm; and 26.5 to 32.0 inches, vernier 

to 0.005 inch. The vernier slide is moved 

directly by hand. Overall length, 87 cm. Transferred from the U.S. Military Academy in 1959. 

Instead of bringing the mercury up to a point, 

why not bring a point, rigidly attached to the 

end of a scale, down to touch the mercury? 

This idea was probably thought of about 1780, 

but not widely applied. In the Museum, this 

principle is represented by an excellent large 

station barometer (MHT 314,941) by John 

Frederick Newman, which may have come to 

the Smithsonian Institution more than a century ago. This famous barometer was designed 

by Newman about 1839 to be sent out to observatories all over the British Empire, and it 

had to be portable as well as accurate, so Newman thought out a cistern which has the two 

square brass tubes between which the large 

barometer tube is supported. Inside one of these 

y 

^^'"^^^S 

38 Paul E. Klopsteg and H. P. Sachse, U.S. Patent 

1,632,084 (1927). See also op. cit. (footnote 2), pp. 352-53. 

FIGURE 14 

Tuch barometer cistern. 

19 
3 0 — 

e) 

-to »~ 

-6 

— 9 0 

-TO 

FIGURE 15 

Adjustable cistern in which the tube can be 

closed for transport. (Smithsonian photo 61224.) 

is the movable rod, tipped with ivory, which 

carries the scale at its upper end. This rod can 

be moved by a rack and pinion and passes into 

the cistern through a mercury-tight gland. 

The two main portions of the cistern are of iron. 

To make this barometer portable it is slowly 

inverted, so that nearly all the mercury passes 

into the tube and the upper chamber of the cistern. The lower chamber is then turned on its 

central bearing so that the communicating part 

is closed off. In this state the instrument can be 

carried upside down or horizontally. The success of the design was shown by the fact that 

most of the instruments, taken out to their remote destinations and set up by soldiers, arrived 

not only intact but with their corrections almost 

unchanged. 

MHT 314,941. Large station barometer with 

movable scale, marked "I. Newman 122 Regent 

St London" and "N° 121 Temp"-* 32 Diameter 

of tiie tube .562." (Temp" 32" refers to the 

temperature at which the scale is standard.) 

The tube, 1.42 cm in internal diameter, is supported between two square tubes ending in a 

semicircular casting at the top, and attached to 

the cistern at the bottom. The movable scale has 

the lower part of iron, tipped with ivory, the 

upper part being a square brass rod to which 

the scale plate, of platinum, is attached. This is 

graduated from 25.75 to 31.00 inches in twentieths, and a vernier reads to 0.001 inch. The 

whole barometer, 121 cm long, is mounted on 

trunions, attached to a board 130 x 20 cm by 

cast brackets, so that it can be turned about a 

vertical axis. The thermometer, which has its 

bulb in the cistern, is not original, being 

marked "J. Green." The knob for moving the 

scale is missing. This barometer was transferred 

from the Smithsonian Astrophysical Observatory in 1956. 

Both the Fortin barometer and the movablescale barometer require one setting and two 

readings, and also demand that the cistern be 

kept reasonably clean. Why not simply read the 

level of the mercury in the tube, providing a 

fixed, non-adjustable cistern and correcting for 

the fall of the level in the cistern as that in the 

tube rises? The easiest way to do this is to make 

20 
i 

FIGURE 16 

MHT 308,187. Mercury barometer signed 

"Tonnelot k Paris," in a lacquered brass 

frame. The tube is 8 mm inside diameter, 

the cistern about 8 cm; therefore, the 

silvered scale is graduated in units of 

0.99 mm from 590 to 820. There is a 

vernier reading to 0.05 mm flush with the 

scale on a sliding sleeve moved by a rack 

and pinion. The scale is inscribed "Echelle 

compensee." Overall length 90 cm. Transferred from the Signal Corps in 1923. 

(Smithsonian photo 61901.) 

the scale in contracted units, chosen so that one 

unit is equal to A/(A+S) standard units, where 

A is the area of the surface of the mercury in the 

cistern, and S the interned cross-sectional area of 

the tube. This procedure, suggested in 1792 by 

Hugh Hamilton,*" became common in British 

ships and stations after 1850, although barometers 

with cisterns that are not full during transport 

are very susceptible to accident. A way of circumventing this difficulty, by having the cistern 

full of mercury during transport but giving it a 

predetermined volume when in use, was devised 

by the Paris instrument maker Tonnelot in the 

19th century. The Museum has one of his 

barometers (MHT 308,187, figure 16). A cross 

section of the cistern shows that the mercury is 

contained between two pieces of boxwood, 

joined by a flexible leather ring. For ti'ansport a 

screw is raised until the cistern is full; in use, it 

is lowered until the movable boxwood piece 

rests on the brass cover, ensuring a well-defined 

volume. 

Of recording mercury barometers, the photographic barograph, first invented by T. B. 

Jordan *^ and greatiy improved in England in the 

succeeding thirty years, proved one of the most 

durable and satisfactory. The improvements 

culminated in the Kew Barograph, which received its final form in 1867.*^ The instrument is 

in essence a lantern-slide projector, the barometer 

tube acting as the slide and the drum covered 

with photographic paper as the screen. Temperature compensation is provided by a zinc rod 

which moves a small plate in front of the drum 

by means of a magnifying lever, producing a 

variable base line on the record. The Museum has 

a replica (MHT 319,425, figure 17) of a much 

simpler model made by a Parisian instrument 

maker about 1865.*^ 

In the last half of the 19th century the great 

advances in the application of electricity, and 

especially of electromagnets, led to the construction of a number of recording barometers with 

electromechanical servo systems. At the cost of 

some complication, these instruments were fi'ee 

from the sort of errors produced by friction in 

barographs derived directiy from the wheel 

barometer or the balance barometer and having 

continuous registration. Of these electromechanical barographs some ** were based on the 

balance barometer, but most of them on the 

siphon barometer with a float in the open limb. 

*" Royal Irish Academy Transactions, vol. 5 (1792), pp. 

117-27. 

*^ Royal Cornwall Polytechnic Society, Annual Report jor 1838, 

pp. 184-89. 

<2 Meteorological Committee Royal Society, Report jor 1867, 

pp. 40-42. 

*' Catalogue des instruments . . . qui se trouvent et sejabriquent 

dans les magasins et ateliers de Deleuil . . . (Paris, rue du 

Pont-de-Lodi, 6, 1865), p. 179. 

" E.g., those of A. Sprung and of C. F. Marvin. For 

details, see op. cit. (footnote 2), chapter 11. 

21 
An early barograph of this sort is in the MuseuM 

(MHT 318,284), though incomplete; it is an 

ingenious and complicated instrument devised 

by G. W. Hough,*^ which not only made continuous records of the barometric pressure on 

two drums revolving at different speeds, but 

also provided a printed record in figures at 

hourly intervals, a valuable feature that removes 

all concern about the expansion or contraction 

of the paper chart. An earlier version, with only 

one drum, was described and illustrated in 

1866.*« 

Hough's barographs were based on siphon 

barometers of large bore. In the earlier model a 

float in the open limb carried a wire, at the top 

of which was a small horizontal platinum disk. 

Two platinum contacts, one above and one 

below the disk, were moved as a unit by a screw 

which was traversed in the appropriate direction 

to break the appropriate contact. In the later 

version the float wire moved one end of a lever, 

platinum-tipped at the other end. The screw 

that moved the contacts was geared to a second 

screw which gave a corresponding but magnified 

motion to the recording pencils. This version 

was further modified by Hough's assistant H. L. 

Foreman,*^ and as the specimens in the Museum 

are far from complete, we have reproduced in 

figure 18 an illustration of Foreman's barograph.*^ 

MHT 318,284. Hough's printing barograph, 

second' version, incomplete. The siphon tube 

is 19 mm in bore. In this instrument the drums 

are moved by a small windlass that unwinds 

cords from the drums. The clock that drove 

this mechanism is missing, as is the float. The 

type wheels exist, but other parts of the printing 

mechanism have disappeared. The overall 

FIGURE 17 

MHT 319,425. Reproduction of a photographic barograph made and sold by 

Jean Adrien Deleuil of Paris in the 19th 

century. A gas lamp illuminates the upper 

part of the tube of a barometer from 

behind. This is imaged by a lens system 

on to a photographic plate, moved horizontally by a clock. It is all mounted on 

a table 81 x 40 cm x 81 cm high. The box 

holding the sensitive plate is 40x27x10 

cm. The total height of the instrument is 

110 cm. Made by L. C. Eichner, 1961. 

(Smithsonian photo 61909-C.) 

^5 Annals oj the Dudley Observatory, Albany, N.T., vol. 2 

(1871), p. xxiv. 

^s American Journal oj Science, 2d ser., vol. 41 (1866), 

pp. 43-58. 

« Op. cit. (footnote 36), pp. 26-29. 

« Ibid., p. 27. 

dimensions of the wooden frame are: 191 cm 

high, 107 cm wide, and 62 cm deep. There is a 

glazed case to enclose the upper part of the instrument. Presented in 1960 by Northwestern 

University, Evanston, Illinois. 

The Museum also has the greater part of a 

similar barograph which seems not to have had 

the printing mechanism (MHT 317,417), and a 

22 
fragment (MHT 314,525) with a different 

mechanism for moving the pens. 

MHT 317,417. A mercury barograph of the 

type designed by G. W. Hough. Incomplete, 

only one of the two drums exists. It appears that 

the drum is moved in small steps by means of a 

cam, ratchet, and pawl. The motion of the pen 

is controlled by two electric switches operated 

through a lever by a float in the open arm of a 

siphon barometer. Two electromagnets control 

a clockwork and a reversing gear which drives 

the pen, the contact system, and the lever in 

such a direction as to restore the contact on the 

lever to a position in which it does not touch 

either of two other contacts. The drive is by 

means of a screw that feeds vertically through a 

constrained nut rotated in either direction by the 

clockwork. The instrument, which measures 

76 cm X 31 cm x 92 cm high, is provided with a 

glazed wooden case 127 x 81 x 40 cm. Presented in 1960 by Dudley Observatory, Albany, 

New York. 

MHT '314,525. Part of the clockwork and one 

drum of a barograph which evidendy resembled 

that of 'H. L. Foreman, and may have been 

designed by him. It diff"ers fundamentally in 

that the pens are operated by a cord or chain 

(missing) passing over a pulley, and not by a 

lead screw and nut. The surviving part is 40 cm 

high X 30 X 21 cm, and apart from the drum, 

which is of wood, is mainly constructed of brass. 

Transferred from the Weather Bureau in 1954. 

FIGURE 18 

Diagram of Foreman's barograph. (U.S. Weather Bureau Circular F, 1894, page 27; Smithsonian photo 63886.) 

Aneroid Barometers and Barographs 

The barometers that we have been considering 

are all variants of the original apparatus of 

Torricelli, balancing the weight of a column of 

the atmosphere against that of a column of 

mercury. The remaining barometers that we 

must discuss are of a quite different sort, measuring atmospheric pressure by the deformation 

of some system of metallic or other solid bodies. 

No liquid is involved, and Lucien Vidie, who 

made the first practical barometers of this sort, 

called them aneroid barometers, ft-om the Greek 

words a, without, and neros, liquid. 

Suggestions for barometers of this kind had 

been made by G. W. Leibnitz in 1698, I. E. 

Zeiher in 1763, and N. J. Gonte in 1798," but 

the technical means were not available to any 

of them. It was left to Vidie to succeed in making 

satisfactory metallic barometers in the face of 

erroneous ideas held by the scientific world about 

the properties of metals. This was in 1843, and 

in 1844 he took out his basic patents.*° His first 

barometer had a corrugated diaphragm supported by 33 helical springs in a strong evacuated 

brass box. A cup was soldered into the center of 

the diaphragm, and a nut in this cup engaged a 

« For details see op. cit. (footnote 2), pp. 398^00. 

60 British Patent 10,157 (1844); French Patent 12,473 

(1844). In 1846 he took out a U.S. Patent 4,702. 

23 
FIGURE 19 

MHT 308,166. Aneroid barometer with Spanish 

markings. It is graduated from 68 to 80 cm and 

from 27.4 to 31.7 inches of mercury. It is of the 

type having the external spring in the form of a 

helix, most of the mechanism being visible 

under a glass plate. It is in a brass case 15 cm 

in diameter and 5.5 cm thick. Presented in 

1923 by Taylor Instrument Companies, Rochester, New York. (Smithsonian photo 61902-A.) 

steep-threaded screw to which the pointer was 

attached. A hairspring took up. backlash, and a 

bimetal provided temperature compensation. 

By about 1847 the instrument had been greatly 

simplified by the use of a flat double-sided 

vacuum chamber and an external spring, at 

that date helical, as in MH T 308,166 shown in 

figure 19. The more familiar flat spring, as in 

figure 20, formed part of a Vidie patent ^^ as early 

as 1845, and this patent also covered various devices for temperature compensation. Aneroid 

" French Patent 1,149 of 1845. 

24 

barometers made at about this time seem to have 

been compensated for temperature by leaving a 

littie air in the chamber, but twenty years later 

it was more common to make the first lever 

bimetallic, as in figure 20, taken from part of 

M H T 323,503, and the great majority of aneroid 

barometers made since that time have had a 

mechanism of this sort. The pattern was set by 

the Paris firm of Naudet & Cie, who called 

their aneroids by the curious name "Holosteric 

barometer," as in a specimen (MHT 230,002) 

in the Museum (figure 21). 

Aneroid barometers tend to be given to 

museums in large numbers, and the Museum of 
FIGUR

E 20 

Assembled mechanism of aneroid barometer 

with new hand supplied. MHT 323,503 has a 

panel 51 x 51 cm, with a labeled display of 

the parts of an ordinary aneroid barometer, 

the assembled nnechanism, and the completed 

instrument, which is of the type with a curved 

spring and bimetallic compensation. Marked 

"Parts used in construction of Tycos Stormo-

guide," and "Taylor Instrument Co. Rochester, 

N.Y. 1922." (Smithsonian photo 61911-A). 

FIGURE 21 

MHT 230,002. Aneroid barometer in brass 

case 12.5 cm in diameter and 5 cm thick, with 

glass front. On the silvered metal dial is marked 

"Holosteric Barometer Compensated" and the 

trademark of Naudet & Cie with the letters 

H, P, B, and N arranged as a cross within a 

circle. The scale is graduated in hundredths of 

an inch of mercury from 28 to 31 inches. 

(The aneroid is graduated in pressure units: 

inches of mercury, millimeters of mercury, or 

millibars—^kilodynes per square centimeter; 

therefore, it would be incorrect to say than an 

aneroid is "graduated in inches.") The pointer 

is blued, and a brass pointer operated by an 

external knob is provided as a reminder of 

the reading at the previous observation. On the 

back is engraved "U.S. Signal Service 1101." 

Deposited by the Weather Bureau in 1904. 

(Smithsonian photo 61831-B.) 

25 
Fiff. 2. 

I'i.. 1. ^ : 

^^-

Accordino; to Fig. 1 in turnino: the 

dividf'd headpiece TT in the sami' mannor '^ 

nn a blockhand runs, the screw Jl/ the spring 

;•;• beside the expanding spring ss which is set 

in motion by the box free from air press dowfi' until 

the heads of the springs e and e' drawn strokes Fig. 2 

liirm a straight line. The reading A by the Index stroke 

is according and the Table to be imyiroved at the head. The ' 

Mark ni is fixed, so that if one presses down in screwing in the 

screw the spring rr so far tliat the head f' comes together with w» 

Fig. 3 the reading must be the same if the Instrument has not 

altered. If it is larger, A is also as much too large and must also be made 

as much smaller or on the contrary. Every cessation takes place above 

downwards. Small differences in comparison with a nonnal 

Queeksilver I?arnnieter can bo set aside by a corresponding 

correction of the Index ring. From thence new reading 

on the fixed Mark. The Instrument must alwaya 

remain in the case. This Aneroid improves with 

I'very year. 

Rending on the fixed Mark; 

•PK-^^'^-* . 

FIGURE 22 

Cross section of Goldschmid's aneroid. (Smithsonian photo 61831-D.) 

History and Technology is no exception to the 

rule. Other specimens are listed at the end of this 

chapter; but we must mention the provision of 

an altitude scale in addition to the scale of 

barometric pressure, a feature first suggested to 

Negretti and Zambra by the Astronomer Royal, 

Professor (later Sir George) Airy (1801-92), who 

provided a calculation based on an isothermal 

atmosphere at 50° F.^^ These were often made to 

52 Negretti & Zambra, A Treatise on Meteorological Instruments (London, 1864), p. 55. 

26 
b e carried in the pocke t like a watch, as in MH T 

247,924, an d wer e sold, bu t probabl y not made , 

b y Jame s Green . 

M HT 247,924. Aneroid barometer with scales 

of pressure and height, in plated case 7 cm 

diameter x 3.2 cm thick. Graduated from 31 to 

15 inches and 0 to 20,000 feet. Marked on the 

silvered face "James Green New York. Compensated" and "U.S. G. S. N° 60." On the 

back, "19. " A milled edge can be used to 

position a pointer. Presented in 1907 by the 

U.S. Geological Survey. 

At the end of the 19th century man y aneroids 

of very high quality wer e mad e for the use of 

surveyors; the Museu m has an excellent exampl e 

(MH T 308,172). 

M HT 308,172. A high-quality aneroid in a 

plated brass case 12.6 cm diameter x 6 cm 

thick, with a beveled plate-glass front. It is 

graduated from 31 to 24.8 inches of mercury 

in fiftieths, and fi-om 0 feet (at 31 inches) to 

6,400 in 10-foot divisions, with a vernier reading 

to one foot, set by an external milled knob 

1.9 cm in diameter. A magnifier on a post can 

be revolved around the rim of the instrument 

for reading the vernier. On the front panel 

is engraved "Surveying Aneroid Compensated 

for temperature Short & Mason London Tycos 

Made in England." This instrument was 

sensitive to a change of height of 1 foot in 1966. 

Presented in 1923 by Taylor Instrument 

Companies, Rochester, New York. 

Because the pressure varies a t a given station, 

it was though t to be a good idea to mak e the 

scale of altitudes movabl e with respect to the 

pressure scale. Th e Museu m has several examples 

of this construction, of which the pocket aneroid, 

M H T 247,927, is typical. But the pressure does 

n o t var y uniformly with altitude, bu t exponentially, an d this procedur e is of limited usefulness 

unless the altitude scale ca n be mad e linear. 

M HT 247,927. Aneroid barometer with movable 

height scale, in a gilt brass case, 6.8 cm in 

diameter and 2.4 cm thick, watch-shaped, with 

a plate-glass front. The scale of heights, 0 

to 10,000 feet in units of 50 feet, can be moved 

by means of a milled rim in relation to the 

scale of pressure, graduated from 31 to 21 inches 

of mercury in Ko-inch divisions. The scale has 

the words "Rain, " "Change," and "Fair " 

at 28.5, 29.5, and 30.5 inches respectively, and 

is marked "Compensated Made in England." 

Presented in 1907 by the U.S. Geological 

Survey. 

This was done durin g the wa r of 1914-18 by 

careful design of the linkage between the aneroid 

chambe r and the pointer; ^^ MH T 308,169 is a n 

instrument of this sort, mad e in 1919. 

MHT 308,169. Aneroid barometer with movable altitude scale, in a plated case 7.6 cm in 

diameter and 3.6 cm high. Graduated from 

31 to 25.8 inches and 0 to 5,000 feet; the altitude scale has been made linear, and in consequence the pressure scale is not. The altitude 

scale can be rotated by means of a milled ring 

so that the height of the starting point can be 

set to the current pressure. On the silvered 

face appears "Compensated for temperature 

Tycos Rochester, N.Y., U.S.A." Presented 

in 1923 by Taylor Instrument Companies, 

Rochester, New York. 

A considerable improvemen t in stability, a t 

the expense of the necessity of setting the instrument before reading it, was mad e abou t 

1857 by instrument-make r J. Goldschmid of 

Zurich. I n his instrument, the capsule is unde r 

n o constraints except the resistance of the spring. 

Ther e are a t least two forms of this instrument, 

bot h represented in the Museum. Th e action of 

the simpler of the two ma y be described by reference to the diagram pasted in the lid of the leathe r 

case of specimen MH T 314,545, shown in 

figure 22, in which bb is the vacuum chamber, ss 

the tension spring, an d rr a second spring pushed 

down b y a micromete r screw operated b y the 

graduate d head TT. Th e ends of the two 

springs ss and rr carry fiducial marks, as shown in 

figures 2 and 3 at e and e' respectively. T o read 

the instrument, the hea d TT is turned until the 

marks e an d e' coincide, an d the pressure read on 

the scale engraved on the rim. Th e mar k m is 

a fixed reference mark, to which e' ca n be 

brough t in orde r to determine whethe r the 

63 Glazebrook, Dictionary oj Applied Physics (London, 1923), 

vol. 3, pp. 180-83. 

27 

2©9-340 O—6Q-
FIGURE 23 

MHT 314,545. Aneroid barometer, 

Goldschmid type, made by Hettinger 

& Co., Zurich. The plated brass case 

is 9 cm in diameter and 6 cm thick, 

the tubes containing the indexes and 

the thermometer are each 0.9 cm in 

diameter and 4.5 cm long. The thermometer is graduated at 2° intervals 

from 40 to 120° F. The index of the 

pressure scale is adjustable over a 

range of about 0.25 inch in pressure; 

the scale itself is graduated from 28 to 

31 inches of mercury in 0.05-inch 

divisions. The circular top of the barometer has a glass bezel covering a 

paper label on which is printed "ShipBarometer N° 116," "Hottinger & 

Co. Zurich," and correction tables. 

There is a shaped case covered with 

black leather. Transferred from the 

Weather Bureau in 1954. (Smithsonian photo 61831-C.) 

calibration has changed. I n the actual instrument, shown in figure 23, an eyepiece is 

provided for the observation of the marks e, e' and 

m, and a thermomete r is installed for determining 

the temperatur e inside the instrument. 

Hottinge r & Co. also mad e anothe r type of 

Goldschmid aneroid in which the tension spring 

is of the familiar curved form, as shown in the 

exploded view, figure 24, ^^ eliminating the eyepiece tube. Th e Museum possesses one of these 

(MH T 314,546). 

MHT 314,546. Goldschn^id-type aneroid barometer, 8 cm in diameter and 5 cm thick. In 

this instrument, intended for mountain use, the 

whole number of inches of mercury is read from 

a small scale near the eyepiece, the movable 

pointer being set to the nearest one of these, and 

the hundredths read on the large scale on the 

cap. Under the glass top is printed "Aneroid 

Barometer No. 3241," "Hottinger & Cie. 

Zurich," and correction tables. Transferred 

from the Weather Bureau in 1954. 

American ingenuity has not contributed greatly 

to the design of meteorological aneroids,^^ bu t 

the Museum has one (MH T 313,693) tha t was 

built unde r U.S . Paten t 24,635 date d 14 Jun e 

1859, issued to Victor Beaumont. Th e paten t 

covered the use of multipl e elastic chambers 

and was really concerned with steam gauges, 

a concern tha t is reflected in the general ap -

pearanc e of the instrument shown in figure 25. 

Naturally there was an impetus to mak e a 

recording instrument out of the aneroid barometer. Th e first successful solution to this prob -

lem seems to have been an instrumen t mad e in 

54 Op. cit. (footnote 36), p. 20. 

28 

Aircraft altimeters are, of course, quite another matter. 
''"I'lir"""-""""'"'^"^''' 

FIGURE 24 

Goldschmid's aneroid barometer, later form, 

exploded view. (From U.S. Weather Bureau 

Circular F, 1894, page 20; Smithsonian photo 

63885.) 

FIGURE 25 

MHT 313,693. An aneroid barometer in a 

cylindrical brass case 10.5 cm in diameter and 

5.4 cm deep, with a scale covering an arc of 

less than 90 degrees and graduated in tenths of 

an inch firom 28 to 31 inches of mercury. The 

scale plate is marked "Beaumont's Barometer 

175 Center Str*. New York Patented June 14th 

1859." (Smithsonian photo 61831-A.) 

or about 1867 and exhibited at the Paris International Exhibition.^^ This used an external 

leaf spring over the three aneroid capsules, and 

was compensated for temperature by leaving 

some air in them.^^ After about 1885, however, 

it became standard practice to use a pair of 

leaf springs in each capsule, as was done by the 

firm of Richard Fr^res in their barograph, one 

of their remarkably complete line of simple 

and effective recording instruments which revolutionized meteorological observation in the last 

68 See R. Radau, Repert. jur phys. Techn., vol. 3 (1867), 

pp. 330-31. 

*^ Annuaire de I'Obs. de Mont-Souris pour Van 1878, pp. 

256-57. 

FIGURE 26 

Standard Richard barograph (MHT 252,981). 

(Smithsonian photo 46740-C.) 

29 
FIGURE 27 

M H T 308,190. Large aneroid barograph by 

Richard Freres, giving a record magnified three 

times on a chart carried by a drum 12.7 cm 

in diameter and 17.3 cm high. There are 16 

aneroid chambers in series, 4.5 cm in diameter, 

with internal springs and probably compensated for temperature by leaving some air in 

one or more of them. The motion of the top 

of this pUe of chambers is transmitted to the 

pen, which is on a 27-cm arm, by two levers 

and a link. A thermometer in Fahrenheit and 

centigrade degrees is attached to the brass 

base. The entire instrument was in a mahogany 

case 40 X 19 x about 26 cm, of which the top 

is now missing. On the baseplate is the Richard 

Freres trademark and the number 82094. 

Transferred from the Signal Corps in 1923. 

(Smithsonian photo 61830-G.) 

years of the 19th century.^^ Th e mai n innovations introduced b y this enterprising firm wer e 

the dru m with which a n integral clock revolves, 

the simple adjustments for scale an d zero, the 

spring clip for the chart paper, an d the familiar 

recording pe n in the form of a triangula r pyra -

mid, split a t the tip.^^ 

58 Notice sur les instruments construits par Richard Freres, 

comprenant le rapport de M. le Colonel Sebert a la Societe 

d'Encouragement pour ITndustrie Nationale, et Vexpose des 

perjectionnements et applications nouvelles (Paris, 1889). 

59 Illustrated, and two of them claimed, in U.S. Patent 

334,613 issued to Jules Richard on 19 January 1886. 

30 

T h e Museum ha s several of the standar d 

Richar d barograph s of the period, of whic h one 

(MH T 252,981) is dlustrated in figure 26. 

MHT 252,981. Transferred from the U.S. 

Geological Survey in 1909. 

M HT 261,255. Transferred from the Department of the Interior in 1910. 

M HT 314,532. Transferred from the Weather 

Bureau in 1954. 

Three aneroid barographs by Richard Freres, 

Paris, mechanically identical, but with slight 

variations in the construction of their wooden 

glass-fronted cases, 28 x 13 x 16 cm. They bear 

the serial numbers 673, 1435, and 8772 respectively, on their brass baseplates. Each has eight 
FIGUR E 28 

MHT 316,288. Friez aneroid barograph with 

a scale magnification of 2.5, and a drum 9.2 cm 

in diameter and 17,5 cm high, revolved once 

in four days by an internal clock. The sensitive 

element is a metal bellows, and there are two 

dash pots for damping. Marked "Signal Corps 

U.S. Army Barograph ML-3-A Serial N° 124 

Order N° 1316-WF-42 Made by Julien P. 

Friez & Sons Baltimore Maryland U.S. Patent 

2,165,744." In glazed aluminum case 33 x 17 x 

24 cm. Provenance unrecorded. (Smithsonian 

photo 61908-D.) 

aneroid chambers in series, the deflection of 

which is communicated to a pen arm, 18 cm 

long, by two levers and one link. The clock and 

drum are Richard Fr^es standard, the drum 

9.2 cm diameter x 9.2 cm high. On number 

252,981 there is a weekly chart graduated in 

inches and tenths from 28 to 31, with the names 

of the days in English. 

On number 314,532 a nameplate notes that 

J. Glaenzer & Co. of 80 Chambers Street, New 

York, are sole agents for the United States, and 

refers to Patent No. 334,613. 

The Museum also has a large model (MHT 

308,190, figure 27) with 16 aneroid chambers 

in series, which gives a record magnified 3 

times in mercury units. 

It is necessary to emphasize that in bringing 

out these simple and relatively inexpensive instruments, Richard Freres were ahead of their 

time, for this was the era of large and costly 

barographs, the era when it was thought that 

the possible accuracy of meteorological observations was limited by that of the instruments, 

instead of by the random spatial and temporal 

fluctuations of the atmosphere itself, and by 

the imperfections of exposures.^" Indeed, Cleveland Abbe was just writing 36 pages on the 

corrections to the mercury thermometer in his 

grea t Treatise on meteorological apparatus and 

methods.^^ 

8" These ideas are developed by W. E. K. Middleton in 

Quarterly Journal Royal Meteorological Society, vol. 72 (1946), 

pp. 32-50. 

«• U.S. War Department, Annual Report oj the Chiej Signal 

Officer . . jor 1887, Appendix 46 (Washington, 11 " 

pp. 41-77. 

31 
Aneroid barographs changed little in essentials 

until about 1920, when a barograph using a 

metal bellows (MHT 308,189) was made by the 

firm of Julien Friez at Baltimore. 

MHT 308,189. Aneroid barograph marked 

"Julien P. Friez & Sons," the sensitive element 

being a bellows 5 cm in diameter and 4.3 cm 

high, with 13 corrugations. The zero adjustment is by a lever beneath the baseplate, 

moved by a milled knob above it. There is a 

hooked link so that the lever system may be 

disengaged from the bellows for transport. 

The mechanism is on an iron base 28 x 13 cm, 

which formed part of a glazed case, now missing. 

Pen radius, 17 cm. Transferred from the Signal 

Corps in 1923. 

In 1928 a larger instrument of this sort with 

magnification of 3 was put on the market, and in 

1939 William Boettinger patented ®^ an ingenious 

use of a bimetal for the shaft of the first lever of 

a barograph. This bends with change of temperature so as to alter the ratio of the two arms 

of the lever. It is used in addition to the device 

of leaving some gas in the bellows, which compensates only at one particular value of atmospheric pressure. The Museum has one of these 

instruments (MHT 316,288), shown in figure 28. 

Before the Richard firm had had their excellent 

idea, there had been several attempts to make 

aneroid barographs. Possibly M. Hipp of Neuchitel was unduly impressed by the explosion in 

the use of electromagnets, for in 1871 he designed 

the instrument (MHT 314,544) shown in figure 

29.^^ Although the large aneroid chambers and 

strong spring must have plenty of control, Hipp 

felt it desirable to use discontinuous recording, 

and made the electromagnet bring a bar down 

FIGURE 29 

«2 U.S. Patent 2,165,744 issued 11 July 1939. 

^ ^eits. bsterr. Meteorol. Ges., vol. 6 (1871), p. 104. 

MHT 314,544. An aneroid barograph marked 

"M Hipp. Neuchatel Suisse 7243." Two large 

aneroid chambers move an arm which records 

discontinuously on a band of paper 7 cm wide. 

The instrument is 30 x 18 x 21 cm overall. A 

glass cover is missing. Transferred from the 

Weather Bureau in 1954. (Smithsonian photo 

46740-D.) 

on the pointer, printing a point every 10 minutes 

on a strip chart. Immediately after this, the chart 

was advanced by a ratchet and pawl. 

It will be seen that the Museum of History and 

Technology has specimens that range over most 

of the history of the barometer, including several 

of the most important American contributions to 

its development. 

32 
Instruments not Referred to in the Text 

Mercury Barometers 

T h e first four of the following mercur y barometers, which ar e shown in figure 1 on page 2, 

wer e all mad e by the New York firm of Benjamin 

Pike& Sons, probabl y in the second quarte r of 

the 19th century. The y form part of a n exhibit 

tha t reconstructs the New York shop of the Pike 

firm, 

316,739. Mercury barometer in a plain but elegant 

veneered mahogany case. This has a boxwood cistern, 

with a leather bottom adjustable by means of a brass 

screw working against a brass plate. The cistern has 

a cover, but the remainder of the tube is exposed; its 

upper part, the silvered-brass scale plate, and the 

thermometer being covered by a glazed frame 12 x22 

cm with a semicircular top. This frame has to be swung 

aside on its hinges in order to set the simple flat-topped 

pointer and vernier. The scale is graduated from 27 to 

31 inches in tenths, and the vernier reads to 0.01 inch. 

There are the usual weather signs, "Rain, " "Change," 

"Fair." The thermometer is graduated from —20 to 

-|-114° F. The scale plate is engraved "Benj Pike & Son 

New York." Overall length, 95 cm. Received in 1959. 

319,958. Wheel barometer in a plain-shaped oak case, 

displaying from top to bottom a gut hygroscope of the 

usual form, 5 cm in diameter, a Fahrenheit spirit 

thermometer graduated from 6 to 112 degrees in 2-

degree steps, the barometer dial 20 cm in diameter, 

and a bubble level set in a brass plate inscribed 

" B. Pike& Sons 518 Broadway New York." The dial 

is graduated from 28 to 31 inches, with the words 

"Storm, " "Much Rain, " "Rain, " "Change, " "Fair, " 

"Set Fair," and "Very Dry. " Besides the blued pointer 

of the barometer there is a brass setting pointer, but 

the knob that moved it is now missing. Overall length, 

94 cm. Presented in 1961 by Mr, Silvio A, Bedini of 

Washington, D,C, 

323,000. Plain, household mercury barometer with a 

boxwood cistern closed at the bottom by a leather 

diaphragm and provided with a brass screw that 

pushed this up for transport. The oak frame covers the 

cistern, and carries a litde carving near the top and 

bottom. The thick tube, 1.2 cm outside diameter and 

about 0.3 cm inside, is nearly all visible. The ivory 

scale plate is graduated from 27 to 31 inches in tenths, 

and there is a vernier reading to hundredths. The scale 

plate is inscribed "B. Pike & Sons 518 Broadway New 

York." At the left-hand side of the tube, opposite the 

scale, is a thermometer graduated from 0 to 125° F, 

and —14 to +42 ° R. The barometer scale has the 

usual weather signs: "Stormy," "Rain, " "Change, " 

and "Fair. " Overall length, 95 cm. Presented in 1963 

by the Physics Department of Wabash College, 

Crawfordsville, Indiana. 

326,144. "Pike's best and most elegant barometer." 

A mercury barometer in a very elaborately carved 

oak case, with a bas-relief portrait of C^eorge Washington on the cistern cover. In a sloping frame of 

ivory, there are two scales graduated fi-om 27 to 31 

inches in tenths, with separate verniers reading to 

0.01 inch. One scale is superscribed "Yesterday" and 

the other "Today." On the upper part of the ivory is 

engraved "Benj° Pike Jun"" 294, Broadway New 

York." There is a thermometer in Fahrenheit degrees 

with a cylindrical bulb, and graduated from —43 to 

-|-159. One of the two ivory knobs for moving the 

verniers is missing, as is a knob at the bottom of the 

barometer for adjusting the volume of the cistern 

when the barometer was to be transported. Overall 

dimensions, 107 x 23 x 9 cm. Received in 1965. 

308,174. Mercury barometer with cistern of the 

Fortin type, with means of closing the end of the tube 

for transport. Similar to MH T 325,999 shown in 

figure 15. Presented in 1923 by Taylor Instrument 

Companies, Rochester, New York. 

319,957. Mercury barometer, Fortin-type, 99 cm 

long. Incomplete. Provenance unknown, but marked 

"Educational Depository, U.C. " 

Mercury Barographs 

316,819. Small portion of the mechaniccd parts of 

Foreman's barograph, with one drum, and parts of 

a protecting glazed-metal case, 43 cm high x 25 cm 

X 23 cm. Transferred in 1959 from the Weather 

Bureau. 

318,283. Portions of a Hough barograph, built on a 

wooden table 108 x 35 cm x 97 cm high. The siphon 

33 
tube, 1.3 cm in bore, remains, but only a little of the 

mechanism, including a weight-driven clockwork. 

The instrument appears to have recorded on a chart 

fixed to a vertical wooden board 42 x 23 cm, which 

is drawn sideways on a rail. Presented in 1960 by 

Northwestern University, Evanston, Illinois. 

Aneroid Barometers 

205,532. Decorative assembly for use on a desk, 

comprising an aneroid barometer, clock, compass, 

and thermometer. The barometer has weather 

indications in Spanish on the dial. It is said to have 

been in the house where the Filipino leader Aguinaldo 

was captured, but is of no scientific interest. 

247.925. Aneroid barometer similar to MH T 247,924, 

described on page 27, but graduated from 31 to 20 

inches of mercury and 0 to 12,000 feet of altitude. 

The scale plate is marked "J. & H. J. Green. New 

York. Ja^. Pitkin. Maker London. Compensated" 

and "U.S. G.S. N° 181." Diameter, 7 cm. Transferred 

from the U.S. Geological Survey in 1907. 

247.926. Aneroid barometer with movable height 

scale, in a gilt brass case, 6.8 cm in diameter and 2.4 

cm thick, with a milled ring to rotate the height 

scale. Pointer missing. Dial marked "Compensated 

J. W. Queen & C°., Philadelphia" and "U.S. G.S. 

N° 197. Transferred from the U.S. Geological Survey 

in 1907. 

247,928. Aneroid barometer in a brass case 4.8 cm 

in diameter and 1.9 cm thick. Glass front, mechanism 

partly exposed. Scales of pressure and height. "N° 

21 U.S. G.S." marked on the back. It is in a mahogany 

box 7.3 X 7.3 X 3.9 cm, marked "A Lietz & Co., 

Opticians, San Francisco." Transferred from the 

U.S. Geological Survey in 1907. 

261.256. Aneroid barometer in brass case 14 cm in 

diameter and 6 cm thick, marked "Barometre de 

Precision Pour stations meteorologiques Alvergniat 

F'"^^ 10, R. de la Sorbonne". Glass front missing, 

pointer damaged. Transferred from the Department 

of the Interior in 1910. 

261.257. Aneroid barometer in brass case 10.7 cm 

in diameter and 4.8 cm thick. Brass setting pointer. 

It is graduated from 68 to 80 (cm). Transferred from 

the Department of the Interior in 1910. 

307,962. Aneroid barometer, thermometer, and clock 

on walnut base. Presented in 1923 by Dr. and Mrs. 

M. L. Turner of Berwyn, Maryland. 

308,167. The mechanism of a large aneroid barometer, mounted on an iron plate 13.8 cm in diameter 

and 0.35 cm thick. The aneroid chamber is 7.9 cm 

in diameter. One link has a means of changing the 

magnification. "Taylor Rochester" is marked in 

white capital letters on the baseplate. Presented in 

1923 by the Taylor Instrument Companies, Rochester, 

New York. 

308,170. Aneroid barometer, "Stormoguide," in brass 

case 13 cm in diameter and 6 cm thick, with an 

elementary treatise on single-observer forecasting on 

the dial. There is a dial at the back for setting the 

instrument to correspond with the height above 

sea level at which it is installed. Presented in 1923 by 

the Taylor Instrument Companies, Rochester, New 

York. 

308,186. Aneroid barometer in a brass case 12.5 cm 

in diameter and 5 cm thick, marked on the dial 

"Barometre Holosterique Compense Naudet & Cie 

Paris Service Meteorologique." The dial is graduated 

from 65 to 80 cm of mercury. There is a brass setting 

pointer. Transferred from the Signal Corps, U.S. 

Army, in 1923. 

313,415. Aneroid barometer in a brass case 13 cm in 

diameter and 6 cm thick. Glass cracked. On the dial 

"U.S. Navy. Made by Taylor Instrument Companies, 

Rochester, N.Y. Tycos." Transferred from the Department of the Navy in 1950. 

314,530. Watch-shaped aneroid barometer 7.0 cm in 

diameter and 2.3 cm thick, graduated from 28 to 31 

inches of mercury in fiftieths. On the dial is marked 

"Compensated No. 1016. U.S. Weather Bureau," 

and "Tycos," with the monogram of Short & Mason, 

London. A pointer can be set by turning a milled 

ring. Transferred from the Weather Bureau in 1954. 

314.547. Aneroid barometer in a brass case 14 cm in 

diameter and 5 cm thick, with a plate-glass front and 

a silvered dial. This is graduated from 17 to 22 inches 

of mercury, in tenths, and also bears the figures 

"10,000, 11,000 . . . 15,000" but no actual height 

scale. Marked "L. Casella Maker to the Admiralty & 

Ordnance. London. Compensated 2634 'For Issue' 

N° 21. " Transferred from the Weather Bureau in 

1954. 

314.548. Aneroid barometer in brass case 12 cm in 

diameter and 4 cm thick, with a glass front. Graduated 

from 22 to 31 inches of mercury in tenths. Bears the 

number "1634" but no maker's name. Transferred 

from the Weather Bureau in 1954, 

34 
314.549. Aneroid barometer of the Goldschmid type, 

similar in general appearance to MH T 314,545 

(figure 22) except in its dimensions. It is in a nickelplated brass case 4.2 cm in diameter and 2.9 cm thick. 

The eyepiece tube and the thermometer project about 

3 cm. It has a scale in divisions of 5 inches of mercury 

in the eyepiece tube, the cap being graduated in units 

of 0.02 inches. It is marked "Hottinger & Co. Zurich 

No. 1132" on the cap. 

314.550. Aneroid barometer with height scale, in a 

plated case 5.5 cm in diameter and 2.2 cm thick, with 

a glass front. The zero of the height scale (—1,000 to 

4-12,000 feet) is opposite 29.5 inches of mercury on 

the scale of pressure. The dial is marked "Semmons 

Oculist Optician 687, Broadway New York." The 

instrument is in a leather case with a thermometer 

and a small reading glass. Transferred from the 

Weather Bureau in 1954. 

314.551. Pocket aneroid barometer, 4.8 cm in diameter and 1.8 cm thick, with a gilt brass case, a glass 

front, and a silvered scale graduated from 25 to 31 

inches of mercury in twentieths, marked "R. & J. 

Beck's Farmer's Barometer 31 Cornhill London 582." 

The instrument is marked on the back "Signal Service 

U.S. Army No. 17." Transferred from the Weather 

Bureau in 1954. 

316,274. Aneroid barometer for use in aircraft. In a 

plated case 13 cm in diameter and 8 cm thick, this 

instrument has a scale graduated from 1100 to 50 

millibars in 2 mb divisions, and marked "R. Fuess 

Berlin-Steglitz 195153 D.R.P. mb. " The case has 3 

shock cords attached 120 degrees apart. Transferred 

from the Weather Bureau in 1959. 

326,964. A pocket aneroid barometer for mountain 

use, in a brass case 5 cm in diameter and 2 cm thick. 

The silvered scale is graduated in cm of mercury and 

in meters of altitude from —500 to +1500, and is 

marked "L. Casella Maker to the Admiralty & Ordnance London Compensated 2311." Presented in 

1965 by Mr. Philip Squire Sampson of Arlington, 

Virginia. 

Aneroid Barographs 

308,171. A conventional aneroid barograph, in a 

mahogany case glazed on the front and ends and 

measuring 31 x 16 x 18 cm. The drum, which contains the clock, bears a chart graduated from 28 to 

31 inches of mercury. On the frame of the instrument 

is marked "Tycos Stormograph Reg*'- U.S. Pat. Off. 

Short & Mason London Made in England." The 

base is labeled "Taylor Instrument Companies 

Rochester, N.Y., U.S.A." by whom it was presented 

in 1923. 

314,531. Aneroid barograph by Richard Freres, in 

essentials similar to MH T 252,981 (figure 26), but 

with a brass base 30 x 16 cm and a glazed, brassframed cover. It has eight aneroid chambers with 

internal springs. The baseplate is marked "Richard 

Freres Constructeurs Brevetes Paris," and "43974 Y." 

Transferred from the Weather Bureau in 1954. 

317,485. Conventional aneroid barograph, similar to 

308,171 above except for the mahogany case. The 

clock in the drum is marked "Pat. 3715. 02." The 

instrument itself is marked with the trademark of 

Short & Mason and "London Tycos." Overall 

dimensions, 36 x 20 x 17 cm. Transferred from the 

Weather Bureau in 1960. 

35 
FIGURE 30 

MHT 322,752. Reproduction of the thermoscope traditionally ascribed to Galileo. A glass 

tube 80 cm long and 0.7 cm in diameter, with 

a pear-shaped bulb at the top, dips into a 

vessel of water 9 cm in diameter and 9 cm high. 

Changes of temperature—and also of pressure— 

alter the volume of air in the bulb and cause 

changes in the level of the water in the tube. 

Copy of instrument in the Museum of the History 

of Science, Florence, Italy, 1963. (Smithsonian 

photo 61900.) 

36 
Chapter 3 

Thermometers and Thermographs 

Early History 

A thermometer is an instrument for quantifying the sensations "hot" and "cold." Temperature is a quantity of a very special sort, and if 

we look into the matter carefully we shall find 

that until recent times it has been necessary to 

specify it in terms of measurable changes in some 

chosen property of some chosen substance.** The 

property usually chosen is the volume, and the 

substance a liquid or a gas, though when a gas 

is used we may also measure the pressure needed 

to compress it to a constant volume. The earliest 

thermometers were air thermometers in which 

a change in the volume of an enclosed quantity 

of air was taken to measure the change in 

temperature. 

Any "meter" must have a scale, and an instrument that shows merely that the temperature 

has changed should be called a thermoscope rather 

than a thermometer. The air thermoscope has 

its origin in a pneumatic experiment performed 

in antiquity by Hero of Alexandria and by Philo 

of Byzantium. A Latin translation of Hero's 

'* See Ernst Mach, Die Prinzipien der Wdrmelehre (Leipzig, 

1896); also W. E. K. Middleton, A History oj the Thermometer and its use in Meteorology (Baltimore: The Johns 

Hopkins Press, 1966), pp. 48-50. 

Pneumatics was printed in 1575,^^ and Italian 

translations in 1589 and 1592 caught the attention of a number of scholars, especially in Italy. 

The pertinent experiment is one in which water, 

partly filling a vessel that is closed except for an 

exit tube, is driven out through the tube by the 

expansion of the air in the vessel when it is 

heated. It was not a thermometer or even a 

thermoscope; it was " a fountain that drips in 

the sun," 

Several lines of evidence converge to persuade 

us that the great Italian philosopher Galileo 

Galilei made this experiment in a form that 

converted it into a thermoscope. This was most 

probably between 1592 and 1600. The traditional 

form of Galileo's thermoscope is shown in figure 

30, which is a photograph of a reproduction 

(MHT 322,752) of an instrument made many 

years after the event, A similar reproduction in 

the Museum collections is MH T 322,754, It 

should be noted that Galileo never published any 

account of his experiment, although in 1612 or 

1613 he claimed in a letter that he had invented 

the thermometer. By this time Santorio Santorre, 

*^ Hieronis Alexandrini spiritalium liber. A Federico Commandino Urbinate, ex graeco nuper in latinum conversus . . . 

(Urbino, 1575). 

37 
who is important in the history of medicine, had 

used the thermoscope as a thermometer in his 

medical practice by measuring the movement 

of the water with a pair of dividers;^® and by 

1611 someone had provided the air thermoscope 

with a scale, as is clear from a figure and a somewhat garbled text in a manuscript bearing that 

date.^^ 

The invention of the air thermometer has 

been claimed for several others;®^ however, the 

instrument is of limited utility at the best, 

because the changing pressure of the external air 

acts on the air contained in the instrument, so 

that it is impossible to separate the effects of 

pressure and temperature. In a room of constant 

temperature it would act as a baroscope, and 

this is the reason for the survival in the Low 

Countries of the peculiar and characteristic 

form of air thermoscope called by Henri Michel 

"le barometre liegeois."^^ This can best be 

described by reference to figure 31, which 

shows a specimen in the Museum (MHT 

322,299). 

Liquid-in-glass Thermometers 

The fact that the pressure of the atmosphere 

varies had become clear by 1650.^° At some time 

in the succeeding decade the sealed spirit-inglass thermometer was invented by Grand Duke 

Ferdinand II of Tuscany, but it should be 

mentioned that a bulb and tube, filled with water 

but not sealed, was used as a thermoscope at 

least as early as 1632 by a French country 

doctor named Jean Rey, who had never even 

heard of the air thermometer.^^ 

The Grand Duke used spirit of wine as a 

thermometric liquid, and sealed the thermometer. 

8* Santorio, Commentaria in artem medicinalem Galeni (Venice, 

1612), part 3, chapter 85, item 10. 

*^ Bartolomeo Telioux, Mathematica maravigliosa ... . 

Paris, Bibliotheque de I'Arsenal, ms. 8525. 

88 See Middleton, op. cit. (footnote 64), chapter 1. 

69 Or "Liege barometer." See Michel, Physis (Florence), 

vol. 3 (1961), pp. 205-12. 

TM See p. 8. 

" See Middleton, op. cit. (footnote 64), p. 27. 

FIGURE 31 

MHT 322,299. Weather glass or "barometre 

licgeois" of clear glass shaped like a teapot 

with a very long, mainly vertical spout, flat 

on the side away from the spout for hanging 

against a wall. When this is partly filled with a 

liquid, the level in the spout will depend on both 

the atmospheric pressure and the temperature 

of the enclosed air. In the fairly uniform temperature of a room, the instrument will act as a 

rough baroscope. 12 cm diameter x 21 cm long. 

Spout 15 cm long. Mounted on a stand. 

Presented by Mr. Silvio A. Bedini, Washington, 

D.C. (Smithsonian photo 61907.) 

38 
FIGURE 32 

M H T 322,750. Reproduction of a Florentine spirit-in-glass thermometer. The spherical bulb is about 6.5 cm in diameter, and the tube is 

94 cm long. There are 230 divisions with the hundreds marked with 

light blue dots of enamel, the tens with white, and the units with black 

dots. Copy of an instrument in the Museum of the History of Science, 

Florence, Italy. 1963. (Smithsonian photo 61911.) 

H e was fortunate in having a superb glassblower 

a t his court, Marian i by name , who mad e these 

sealed thermometers in several sizes, ^^ all with 

the degrees marke d with beads of glass of various 

colors, as in the replica in the Museum (MH T 

322,750, figure 32). Ther e wer e n o fixed points, 

a n d the remarkabl e comparability of those tha t 

have been preserved must hav e been du e to the 

skill of th e glassblower^ a situation tha t obviously 

left muc h to be desired. Th e subsequent history 

of the thermomete r is very largely tha t of attempts 

to construc t thermometers tha t could be mad e 

comparabl e from first principles. This led to mor e 

tha n a score of different scales of temperature , 

some, like those of Hooke^^ an d Reaumur,'^* with 

one fixed point; others, like the scale of Fahren -

heit ^® an d the centigrade scales,^® with two. Of 

all these scales, only three survived into the 19th 

" The making of them is described in the first chapter of 

the Saggi di naturali esperienze jatte neWAccademia del Cimento 

(Florence, 1667), published by the short-lived Academy 

of Experiments as an account of their work. 

" Robert Hooke, Micrographia . . . (London, 1665), pp38-39. 

''* Ren6-Antoine Ferchault de R6aumur, Mem. Acad. r. 

des Sci. Paris (1730), pp. 452-507; ibid. (1731), pp. 250-96. 

7s Daniel Gabriel Fahrenheit, Phil Trans, vol. 33 (1724), 

pp. 78-79. 

century—the centigrade scale an d those of 

Fahrenheit an d Reaumur—an d now only the 

first two ar e in general use anywhere . It was 

commo n in the 18th century to pu t a numbe r of 

scales beside a thermomete r tube , an d a t least 

two exist with 18 each. By the end of the 18th 

century, we find man y with multiple scales, as 

in the thermomete r reportedly carried by Dr. 

Joh n Jeffries of Boston on his balloon ascensions 

in 1784 an d 1785. 

NASM 1963-28. Mercury thermometer with 

scales of Reaumur and Fahrenheit, marked 

" T . F. Poole [or T. & F. Pool?] Boston." 

Mounted in a glass-covered case 73 cm x 6 cm. 

Ther e ar e also multipl e scales in the specimen, 

M H T 316,451, which wa s used in the early 19th 

century in the teaching laboratories of the U.S . 

Military Academy. 

M H T 316,451. Early-19th-century mercury 

thermometer with scales marked Reaumur, 

Fahrenheit, and Celsius, mounted on a board 

5.3 X 34 cm. The scale and other markings are 

almost obliterated. Transferred from the U.S. 

Military Academy in 1959. 

" Such as that of Anders Celsius, Kongl. Svensk. Wet. 

Akad. Handlingar, vol. 3 (1742), pp. 171-80. The history of 

these scales is complicated; see Middleton, op. cit. (footnote 

64), pp. 89-105. 

39 
While the Reaumur scale was originally intended to have only one fixed point, the freezing 

point of water, each degree being defined by an 

expansion of 1/1000 of the original volume of the 

spirit of wine that he used, it was soon modified 

by other people and referred to a mercury thermometer with the melting point of ice at 0° R. 

and the boiling point of water at 80° R. The 

Fahrenheit scale, originally referred to the ice 

point and "blood heat," soon came to have the 

boiling point at 212° F, Towards the end of the 

18th century, the upper point was obtained by 

hanging the theimometer with the bulb above 

boiling water, and became the steam point. 

Thus, we now have: 

The centigrade (or Celsius) 

scale, used for scientific purposes in English-speaking 

countries and for all purposes 

elsewhere. 

The Fahrenheit scale, in general use in English-speaking 

countries. 

The Reaumur scale, now 

obsolete. 

Ice 

point 

0° 

32° 

0° 

Steam 

point ^^ 

100° 

212° 

80° 

For certain purposes in meteorology and engineering, the Kelvin or absolute scale is convenient. In this, the ice point is 273° K ^^ and the 

steam point 373° K. The Museum has an English 

thermometer graduated on the absolute scale 

(MHT 314,556, figure 33). 

The technical improvement of the thermometer 

as a piece of apparatus is partially represented 

in the collections. In France during the 18th 

century the thermometer tube was generally 

mounted on a wooden board, sometimes covered 

with paper on which the scale was drawn; 

sometimes not, as in specimen MH T 316,451 

previously mentioned. Bulbs were usually spherical, Fahrenheit and his successors in Holland 

FIGURE 33 

MHT 314,556. Thermometer on porcelain base, 24 x 3.6 x 0.6 cm. The 

spherical bulb, 0.9 cm in diameter, 

projects 4 cm below the base. This 

thermometer is graduated on the whitebacked tube, and numbered on the base. 

The scale runs from 243 to 325 degrees 

absolute (Kelvin). The tube is marked 

with the monograms of Kew Observatory, 

N. & Z., and the Meteorological Office, 

the last with the number "29." Calibration 

marks at 273° and 320° K, The base is 

marked "Absolute" and "Negretti & 

Zambra, Scientific Instrument Makers, 

London" and has their monogram. Transferred from the Weather Bureau in 1954, 

(Smithsonian photo 61901-C.) 

" - 1 

S 3I(^ 

1 ~: 

i 3Qo: 

1 - i 

1 m 

1 ^ 

i -aaoi 

i 

'''' At a standard atmospheric pressure, defined by international agreements. 

7* More precisely 273.15°. 

used cylindriccd bulbs for the most part, and 

mounted their thermometers on neat strips of 

sheet brass on which the scales were engraved. 

Ivory was often used for the scales of small 

thermometers, as in MH T 327,557. 

MHT 327,557. Very small pocket mercury-inglass thermometer, the glass part only 6.5 cm 

long, mounted on a thin ivory panel 7.2 x 1.8 

cm, carrying the scale, —20 to +50 [°C ?]. 

Spherical bulb. The ivory panel slides into a 

sheath of dark wood with neat ivory stringing. 

Received in 1965. 

A way of protecting the scale from the weather, 

devised about 1810, was to draw it on paper, 

roll this into a cylinder, and enclose it and the 

thermometer tube in an outer sheath of glass. 

The Museum has an early example, designed 

as a bath thermometer" (MHT 316,458). 

MHT 316,458. Bath thermometer, probably 

dating from about 1810 or thereabouts. An 

outer protective tube 24 cm long and 1.4 cm 

in diameter has a spherical bulb, now broken. 

40 
FIGURE 34 

mriTnTTTt^TriTTfrnTTiTifniitmTfrnlTmiruiiiiiilfifim^ 

MHT 316,459. Thermometer, 23 cm long with enclosed rolled-paper 

scale graduated -32 ° to +55° R and -40 ° to +150° F and marked 

"Thermometer nach Reaumur & Fahrenheit." Transferred from the 

U.S. Military Academy in 1959. (Smithsonian photo 61833-B.) 

^fe^ ^ ^^WiPiPilP 

^ [i) n^g" =5=:gP -y-n-py "W ^;pjit;».tiipiii|iii!|'mii^tiiij!WiM 

FIGURE 35 

MHT 316,446. Handsome enclosed-scale mercury-in-glass thermometer 48 cm X 1.6 cm, with ellipsoidal bulb. Milk-glass scale in 

fifths of a degree, —23° to +50°, and marked "Celsius." No maker's 

name. Brass cap. Transferred from the U.S. Military Academy in 

1959. (Smithsonian photo 61899-A.) 

at the bottom, which must have been filled with 

mercury in order to make the thermometer 

float upright. This outer tube encloses a thermometer with red spirit and a rolled-paper 

scale, graduated from —35 to +80° R, The 

scale carries the legend "Thermometre de bain" 

and a number of indications, such as "Eau 

bouillante" at +80 to "Paris 1740" at -11 , 

"1777" at -16 , and "1788" at -17.5. "Syrie" 

is at +50; "Chaleur humaine" at +32.5; 

"Bain" at +26; "Ver a Sole" at +19, and so 

on. Transferred from the U.S. Military Academy in 1959. 

The Museum also has a later, more meteorological instrument (MHT 316,459), which is 

shown in figure 34, 

A better way is the enclosed-scale thermometer 

almost universally used in central and eastern 

Europe for both meteorological and chemical 

purposes under the name Einschlussthermometer. 

We shall call it the "enclosed-scale thermometer," 

noting by reference to figure 35 the milk-glass 

scale fastened to the thin thermometer tube and 

enclosed in an outer tube which is hermetically 

sealed, the bulb being left free. The Museum has 

many such thermometers, some of which wUl be 

more particularly referred to below, 

Chemiccd thermometers in most other countries usually have the scale etched on the tube 

itself, a construction probably invented shortly 

before 1800, and greatly improved in 1844 by 

Bodeur, who provided the tube with a ribbon of 

white glass to act as a background for the mercury 

(or spirit) and the scale.^® Except for the circumstance that they may have been used as standard 

thermometers for calibration in meteorological 

observatories,*" such instruments scarcely have a 

" Bodeur, Comp. Rend. Acad. Sci., vol. 18 (1844), p. 1132. 

8" See Leonard Waldo, "Examination of Thermometers 

at Yale Observatory," Popular Science Monthly, vol. 18 

(1880-81), pp. 367-74. 

41 
1 

j 

i 

i 

i j 

t*-* 

''.'' •*^ ^ 

.~ 

~^ 

•'< ; 

s 

St 

'^ 

•w 

in 

CO 

o 

"* 

o. 

^ 

rS —110 

—I- . 

— _^ 

' 

Eg-100 

-

z 

E§—00 

— — 

E§-HO 

-— — 

-

ES 

Efe 

- 7 0 

- 6 0 

IE§—40 

1^—30 

:ES-2o 

;§£—10 

:EP_O 

place in this catalog, but we shall mention one 

that qualifies on the basis of the above rule 

(MHT 317,451). 

MHT 317,451. Nickeled brass tube, 55 x 1.4 cm, 

with screwed caps, containing a mercury 

thermometer 51 cm long, with a cylindrical 

bulb blown directiy from the tube with its 

white-glass strip. Scale —4.8 to 104.6° G in 

fifths on the tube. Marked "Yale Observatory 

Standard N° 51. Made by Tonnelot a Paris. 

Equal graduations. Crystal-glass tube made 

April 1879." Transferred from the Weather 

Bureau in 1960. 

The point of noting the kind of glass and the date 

of manufacture is that a slow secular change in 

the readings was normal in thermometers made 

at that time, though this has since been greatiy 

reduced by better glasses and improved manufacturing techniques. 

Coming back to meteorological thermometers, 

we find that the brass mount favored by Fahrenheit was preferred by the British Navy, and a 

FIGURE 36 

MHT 317,456, Mercury-in-glass thermometer on a flat 

brass mount 25 x 2.2 x 0.2 cm. Total length 30 cm. 

Cylindrical bulb. Scale, —10 to 125 [°F] on the mount 

only; the tube is located by a nib in a hole near one 

end of the mount. The tube has a white-glass strip; 

the bulb is not blown integral. Mount engraved "J. 

Green N. Y. Sig. Ser. U.S.A. S 184." Transferred from 

the Weather Bureau in 1960. (Smithsonian photo 

61830-D,) 

FIGURE 37 

MHT 317,455. Mercury-in-glass thermometer in a 

brass mount 24 x 2.4 x 0.15 cm with a formed groove. 

Total length 28 cm; cylindrical bulb. Scale, —40 to 

120 [°F] on tube, numbers and major divisions repeated 

on mount. Tube marked "U.S. 11065." Mount marked 

"H.J. Green B'klyn. N. Y. N° 11065 U.S. Weather 

Bureau." Transferred from the Weather Bureau in 1960. 

(Smithsonian photo 61832-C,) 

42 
Bnijuiii^wiijbw4^i,jjilLiiiiiiii|iiiiiiliiliiij<jiiJJ3a>aj|i.ijjJ,iiiu;f»r4^ 

Y 

w 

FIGURE 38 

MHT 316,263. Four Russian earth thermometers designed for depths of 5, 10, 15, and 20 cm 

respectively. They are mercury enclosed-scale 

thermometers graduated in half-degrees C, 

with short cylindrical bulbs about 0.8 cm in 

diameter x 1.2 cm long, the last 2 cm above 

the bulb bemg bent up at 45°, They all bear 

a trademark or monogram and three of them 

the legend "rocT 112-41." The parts of the 

protecting tubes that are to be buried are 

packed, apparently with glass wool or cotton. 

The whole is in a wooden box 58 x 12 x 3.7 cm. 

Transferred from the Weather Bureau in 1959. 

(Smithsonian photo 61899-D.) 

standard model was designed at Kew Observatory in 1854, whereupon a thousand such thermometers were immediately ordered by the 

Smithsonian Institution, half from Casella & Co. 

and half from Negretti & Zambra. ^^ Thermometers of this kind were soon made in the United 

States by James Green, one of whose thermometers, supplied to the Signal Service of the U.S. 

Army about 1880, is in the Museum (MHT 

317,456, figure 36), It will be noted that the 

scale is on the mount only, so that its accuracy 

depends on the tube maintaining its position. 

Two decades later, James Green's nephew and 

successor had improved the design by etching the 

scale on the tube itself, and by forming a groove 

in the brass strip, which not only gives the thermometer better support, but stiffens the mounting. This design is illustrated by MH T 317,455, 

figure 37. Eventually, stainless steel was substituted for brass, with a further increase in 

durability. 

Meanwhile for fixed stations the British were 

using thermometers mounted on porcelain backs, 

as in the one previously discussed (MHT 314,556, 

figure 33). To render the scales impervious to 

the weather, they later combined the chemical 

^1 Kew Committee (J. P. Gassiot, chairman), B.A.A.S., 

Liverpool, 1854, Report oj Council, p. xxvii. 

thermometer and the Einschlussthermometer into 

an instrument having the scale, with its numbers, 

engraved on the tube, a construction introduced 

in 1931 and still in vogue. 

Rather special thermometers aie used for measuring the temperature of the soU at various 

depths. For small depths, thermometers can be 

encased in wooden rods shod with metal, as in 

two specimens in the Museum (MHT 316,008) ^2 

intended for the use of gardeners, for instance in 

cold frames, 

MHT 316,008. Two mercury thermometers, 

each in a wooden mount with a bluntiy pointed 

brass end, total length 30 cm, diameter 2.2 cm. 

The scale, on wood, appears in a cutaway 

portion near the top. Intended for gardeners. 

Marked "L. Casella London." One thermometer has the scale graduated from 20 to 

130° F, the other from 30° to 120° F. Deposited 

by the Smithsonian Astrophysical Observatory 

in 1958, 

In Europe, more systematic observations of this 

kind are often taJsen with enclosed thermometers 

having the last part of the tube before the bulb 

bent up, as in a set of Russian thermometers 

shown in figure 38 (MHT 316,263). They are 

installed in the soil with the bulb horizontal at 

See L. Casella & Co., Catalogue of 1871, p. 46. 

43 

39.9-340 O—(69-
FIGURE 39 FIGURE 40 

FIGURE 39 

MHT 314,558. Thermometer with a bulb in the form of 

a narrow tube about 2 mm in outside diameter, bent 

16 times to form a rectangular grid 6x 3 cm, with 14 

bars. The scale tube is 51 cm long, marked in half 

degrees from —18 to +120. The whole is mounted on 

a hardwood board 64 x 5.8 x 1.5 cm, with brass mounts 

and a hanging ring. The board carries an engraved 

"A" near the top, but no indication of origin. Transferred from the Weather Bureau in 1954. (Smithsonian 

photo 61899-C.) 

FIGURE 40 

MHT 317,459. Minimum thermometer of Rutherford 

type, length 36 cm. Mounted on a metal plate 30 x 2.3 

X 0.1 cm, with formed groove to stiff"en it. Cylindrical 

bulb. Scale, —90 to +110° F, on tube, also numbered 

on the mounting, which is marked "H.J. Green B'klyn. 

N. Y. U.S. Weather Bureau. Minimum." Transferred 

from the Weather Bureau in 1960. (Smithsonian photo 

61909-D.) 

the appropriate depth and the stem sloping backwards at an angle of about 45 degrees. Plainly 

such an installation involves disturbing the sod a 

good deal, For greater depths a strong tube with 

a point at the end is forced into the soil or thrust 

down a borehole, and a thermometer having its 

bulb surrounded by a mass of something with a 

large capacity for heat, commonly paraffin wax, 

is lowered into the tube. 

The idea of the paraffin wax is to prevent the 

indications of the thermometer changing appreciably while it is being read. With the opposite 

goal of making a thermometer respond as 

quickly as possible, very elaborately shaped 

bulbs have sometimes been constructed, of which 

our specimen MH T 314,558 (figure 39) is an 

extreme example. Such thermometers are likely 

to be more greatiy aff"ected by the secular 

changes previously mentioned on page 42. 

44 

120^ 

11& 

im 

•J mm 

m 

so 

# 

40 

109 

95 

20 

46 
FIGURE 41 

MHT 315,998. Maximum thermometer invented by John Phillips in 

1832. Its metal back is marked "Prof."" Phillips's Maximum TherF L. 

Casella & C° fecit London 186." The scale, marked on the tube and 

numbered on the metal back, runs from —30° to +160° [F], The 

tube has a white-glass strip behind the bore. Overall length, 35 cm. 

Deposited by the Smithsonian Astrophysical Observatory in 1958. 

(Smithsonian photo 61900-D.) 

Maximum and Minimum Thermometers 

The highest and the lowest temperature during 

the day have long been of interest. The first 

practical construction of thermometers to register 

these quantities was due to Lord Charles Cavendish and dates from 1757,*^ but these instruments, 

while ingeijious, were elaborate and hard to 

transport. But in 1790 a pair of thermometers 

were devised by John Rutherford, a Scottish 

country doctor, of which his minimum thermometer is in essentials the one used almost universally by meteorological services today. The 

maximum, which was simply a mercury thermometer with a conical index of ivory, has long 

been superseded. The Rutherford minimum 

thermometer was a spirit thermometer containing a conical glass index with its point towards 

the bulb and immersed in the spirit. By 1826 at 

the latest the little cone had evolved into a 

dumbbell of dark glass,^* and so it remains. 

The Museum has about a score of these 

Rutherford-type minimum thermometers, of 

which MH T 317,459, figure 40, is a fairly 

recent example. 

The first reasonably successful maximum 

thermometer was invented in 1832 by John 

Phdlips, a geologist.85 It was just a mercury 

thermometer in which about a centimeter of 

the column is separated from the remainder by 

a tiny speck of air. The instrument is installed 

in a horizontal position, and the short detached 

part of the column remains stationary when the 

mercury falls, and acts as an index. The Museum 

possesses two of these thermometers, one of which 

(MHT 315,998), is shown in figure 41. Such 

instruments continued to be made until at least 

1875, but were eventually superseded by the 

well-known maximum thermometer with a constriction in the tube, now also used universally 

as a clinical thermometer. It was patented by 

Negretti & Zambra on 8 March 1852.*« Mercury 

is forced past the constriction when the temperature is rising, but as soon as it begins to 

cool the column breaks off at the constriction, 

leaving the outer end of the mercury thread to 

indicate the maximum temperature. The column 

is reunited by centrifugal force, usually by 

swinging it, a process which is occasionally 

disastrous to the thermometer. About 1905, in 

an attempt to improve this process, the U.S. 

Weather Bureau introduced a special holder for 

the maximum and minimum thermometers 

known as the Townsend support, ^^ which enables 

83 Phil. Trans., vol. 50 (1757), pp. 300-10; Middleton, 

op. cit. (footnote 64) pp. 150-52. 

8* K. L. G. Winckler, Annalen der Physik, vol. 6 (1826), 

pp. 127-32, 

''^ B.A.A.S. Report, Oxjord, 1832, Sections, pp. 580-81. 

88 British Patent 14,002 of 1852. 

87 U.S. Weather Bureau, Instructions jor Cooperative Observers, 3rd ed. (Washington, 1906), pp. 17-18. 

45 
MAXIMUM 

FIGURE 42 

MHT 308,198. Townsend support, with standard maximum and minimum thermometers. The base, 7.9 x 5.2 

cm, is to be screwed to a vertical surface, and is arranged 

with two posts so that the minimum thermometer is 

held 2.5 cm, and the maximum 6 cm, in front of the 

base. The thermometers are marked "H. J. Green 

B'klyn. N.Y. No. 41500 Signal Corps U.S. Army Maximum" and "H. J. Green, B'klyn. N, Y. No. 44505 

Signal Corps U.S. Army Minimum" respectively. The 

base is marked "Julien P. Friez & Sons." Transferred 

from the Signal Corps in 1923. (Smithsonian photo 

61904-A.) 

the maximum thermometer to be released from 

its normal horizontal position and whirled 

rapidly round, and also permits the minimum 

thermometer to be tilted to let the index slide 

down to the end of the spirit column. The 

Museum has two of these assemblies, of which 

M H T 308,198 is illustrated in figure 42. 

As long ago as 1782, James Six of Canterbury 

invented the combined maximum and minimum 

thermometer that bears his name.^^ In its household form this is probably the most familiar of 

all meteorological instruments except the wind 

vane. It needs little description other than to 

emphasize that the thermometric fluid is alcohol 

contained in a relatively large bulb, the mercury 

being only a means of indication, confined 

between two volumes of alcohol, of which the 

smaller is given a littie room to move. About 

1790 Joseph Gatty, an Italian who had settied 

in Philadelphia, made one of these thermometers 

for George Washington's house at Mount 

Vernon. The Museum has a modern (1960) 

replica of this (MHT 317,699, figure 43), the 

88 Six, Phil. Trans., vol. 72 (1782), pp. 72-81. 

46 
FIGURE 43 

MHT 317,699. Reproduction of a maximum-andminimum thermometer of Six's type. The original was 

constructed about 1790 by Joseph Gatty. The glass 

parts are mounted on a mahogany board 40 cm x 8 

cm X 1 cm thick. The scales, —30 to +150 [°F] 

for the maximum, —50 to +125 for the minimum, 

are engraved directly on the wood, the numbers being 

stamped. The indexes are small pins sheathed in glass 

dumbbells. Copy of an instrument preserved at 

Washington's home, Mt. Vernon, made by Val 

Hergesell and William Bridges in 1960. (Smithsonian 

photo 61899.) 

FIGURE 44 

-Tl 

FIGURE 43 

FIGURE 44 

MHT 314,533. "Kiosk" thermometer intended for 

public display. A modified Six's maximum and minimum thermometer with the ends of the tube bent at 

right angles for 10 cm behind the flat metal base, 

40 X 5 X 0.1 cm, on which the tube is mounted. 

Graduations on the tube, repeated, with figures, in 

white on the blackened base, —40 to +110 [°F]. The 

tube is marked "U-S N° 32;" the base "U.S. Weather 

Bureau No 32 Taylor Instrument Companies Rochester, 

N.Y, Tycosr" and a trademark. The liquid is "composed of alcohol and creosote." Transferred from the 

Weather Bureau in 1954. (Smithsonian photo 

61900-A,) 

r' 

glass parts of which are very like those in Six's 

instrument. 

The trouble with thermometers containing both 

mercury and alcohol is that the latter wets the 

glass, and can be gradually transferred past the 

mercury, changing the zero of the instrument. For 

this and other reasons, this type of thermometer 

is not used for serious meteorological observations; 

but the Museum has a special form (MHT 

314,533) that was part of the instrumentation of 

a "kiosk" devised by the Weather Bureau for 

displaying meteorological information to the 

47 
FIGURE 45 

M H T 314,560. Hicks' vacuum thermometer with electrodes. A 

mercury maximum thermometer, 38 cm long, enclosed in an evacuated 

jacket which has a spherical bulb, about 5.6 cm in diameter, concentric with the thermometer bulb. The tube has a white-glass back 

strip. The scale, —5 to +19 2 [°F] is marked on the thermometer 

tube, and also "202 J. Hicks. 8 Hatton Gar° London Hicks's Patent 

N? 3647 [Kew Observatory monogram] 14951." Near the ends of 

the jacket are two platinum electrodes for connecting to a spark 

coil so that the vacuum could be checked. Transferred from the Weather 

Bureau in 1954. (Smithsonian photo 61832-A.) 

public.8^ Th e thermomete r itself is shown in 

figure 44. 

Ther e were various modifications of Six's 

thermometer, one of which was straight an d ha d 

mercury for a thermometri c fluid, with naphth a 

above it, with two indices, one pushed u p by the 

mercury an d the other draw n back by the 

naphtha.^" This ma y hav e inspired H . J. Green 

to design two soil thermometers tha t ar e in the 

Museum (MH T 314,540 an d 314,541). 

M HT 314,540. Soil thermometer in a wood 

and brass frame, 59 cm overall. The construction of this is not clear. It contains mercury 

and a transparent liquid, and there are two 

dumbbell-shaped indices in the tube. The 

column is now broken up. A nickeled scale is 

adjacent to the upper part of the tube, which 

is exposed by cutting away the wood. The tube 

is graduated from —20 to +17 7 [°F], and also 

numbered on the metal. The scale is marked 

"H.J. Green B'klyn. N.Y. N° 8 U.S. Weather 

Bureau." Transferred from the Weather Bureau 

in 1954. 

M HT 314,541. Soil thermometer, similar to 

M H T 314, 540, but 66 cm overall. The scale, 

from + 5 to +15 2 [°F] is marked "N? 11 U.S. 

Weather Bureau." On a brass band 35 cm 

from the lower end is engraved "Henry J. 

Green B'klyn. N.Y. c»12 in." The column is 

now broken up. Transferred from the Weather 

Bureau in 1954. 

O n e use for a minimu m thermomete r is to 

study the incidence of groun d frost b y puttin g it 

just above short grass. For this use, thermometers 

frequentiy have their scales protected b y a glass 

tube , either hermetically sealed or, as in MH T 

314,553, attached with cement. Similarly a maxim u m thermometer, usually with the bul b blacked 

a n d the whole thermomete r enclosed in a vacuu m 

jacket, used to b e employed to estimat e the 

radiation from the sun.^^ A refinement of this wa s 

to have two similar thermometers, one wit h the 

89 C. F. Marvin, The Weather Bureau Kiosk (Weather 

Bureau no. 522) (Washington, 1914), pamphlet, 6 pp. 

9" John G. Macvicar, Chemical Society Journal, vol. 11 

(1859), pp. 106-7. 

91 Negretti & Zambra, A Treatise on Meteorological Instruments . . . (London, 1864), pp. 86-87, claimed to have 

invented the vacuum black-bulb thermometer. 

48 
FIGURE 46 

MHT 308,948. Thermometer of G.W. Schumacher. A thermometer operating on the 

differential expansion of ebonite and brass, 

the expansions of two hard-rubber strips each 

19 cm long being added by a lever system and 

communicated to a spring-loaded pointer. The 

pointer can move two light indexes on a curved 

rod, to indicate the maximum and minimum. 

The scale, from -4 0 to +140 [°F] is marked 

"G.W. Schumacher Portland, Me." Schumacher 

was awarded U.S. Patent 172,181 on 11 January 

1876. Overall length 29 cm, width 11 cm. This 

was a Patent Office model, and was transferred 

from the Patent Office in 1926. (Smithsonian 

photo 61833-D.) 

bulb blacked, the other with it bright, ^^ The 

Museum has a French thermometer of this sort 

with a bright bulb (MHT 314,559), One of the 

difficulties of this technique is that the vacuum 

has to be very good, a serious problem in the 19th 

century, and in 1874 J, Hicks of London had the 

ingenious idea that the electrical discharge might 

be used to check the vacuum, ^^ and provided his 

thermometers with electrodes for the purpose, as 

in MH T 314,560, figure 45. Now, these techniques 

are only of historical interest, 

MHT 314,553. A grass-minimum thermometer 

of the Rutherford type, 30 cm long. All but 

the spherical bulb and the last 1.5 cm of the 

tube is sealed with black cement into a heavy 

outer glass tube 1.2 cm in diameter. Scale 

— 77 to +135 [°F]. Marked on the thermometer 

tube: "J. & H.J. Green. N.Y. Signal Service 

U.S. Army No 11." Transferred from the 

Weather Bureau in 1954. 

MHT 314,559. Mercury thermometer 40 cm 

long, enclosed in a 15 mm diameter jacket with 

a spherical bulb 5 cm in diameter. The jacket, 

presumably evacuated, has "N" 1" marked 

on it. On the tube of the thermometer, graduated 

in fifths from —20° to +82.2° C, is marked 

"(Centigrade) J. SaUeron 24 rue Pavee (au 

Marais) Paris." Transferred from the Weather 

Bureau in 1954. 

Bimetallic Thermometers 

Solid substances change their dimensions to 

varying degrees as their temperature changes, 

but to an extent much less noticeable than 

liquids, indeed so littie that special techniques 

had to be developed before the expansion of 

solids could be useful for the construction of 

thermometers. 

The answer was the bimetallic strip or bimetal, 

a compound strip made by riveting, soldering. 

92 The idea originated with Sir John Leslie, who applied 

it to his differential thermometer, and called the result a 

pyroscope. See Leslie, On the relations oj air to heat and 

moisture (Edinburgh, 1813), p. 50. 

9» Hicksj Quarterly Journal Meteorological Society, vol. 2 

(1874), pp. 99-102. 

49 
or preferably welding together two strips of 

different metals, appropriately chosen so as to 

have widely diff'erent coefficients of expansion. 

The curvature of such a compound strip changes 

with change of temperature. Today, one of the 

metals is usually a special nickel steel that 

combines resistance to corrosion with an expansion that is very nearly zero. 

It is almost certain that a pocket metallic 

thermometer made in 1767 at Norriton (now 

Norristown) in Pennsylvania by the celebrated 

American instrument maker David Rittenhouse 

used a bimetallic strip.^* If so, this is the earliest 

one that we know about. Ten years later J. H. 

Lambert wrote that someone in England had 

thought of the idea.^^ 

Bimetallic thermometers are used less frequently as indicating instruments than in thermographs or in thermostats. During the 19th 

century, however, there was a vogue for pocket 

thermometers of this sort. There is one in the 

Museum (MHT 325,408), which is referred to 

here even though it qualifies as a meteorological 

instrument only because it is supposed to measure 

the temperature of the air. 

MHT 325,408. Metallic thermometer in the 

shape of a watch 5.0 cm in diameter and 1.2 cm 

thick, with glass front and back. There is a 

white dial with concentric scales from —41 to 

+51 [°C], -3 0 to +40 [°R], and -3 8 to +122 

[°F], over which a thin blue pointer moves. 

There are two brass setting hands. The instrument, unsigned, is in a brown leather case 6 cm 

in diameter x 1.5 cm thick. Received in 1964. 

An instrument that is not strictly a bimetallic 

thermometer, but does operate with the diff'erential expansion of solids is MH T 308,948 

(figure 46). The solids are brass and ebonite 

(hard rubber), but the latter though having a 

relatively great expansion is not a very stable 

substance, and the instrument has little scientific 

importance. 

Recording Thermometers 

Recording thermometers, often called thermographs, have been made on the principles of the 

air thermometer, the liquid-in-glass thermometer, 

and the metallic thermometer.^^ A special kind 

of metallic thermometer, the Bourdon tube, has 

also been used for this purpose. It is really a 

liquid-in-metal thermometer—a curved tube of 

elliptical cross section, entirely filled with a liquid 

such as alcohol, and changing its curvature as 

the liquid expands or contracts. 

The oldest thermograph in the collection is a 

rather extraordinary instrument (MHT 317,416) 

devised by G. W. Hough of the Dudley Observatory, Albany, New York, about 1860. Instead of 

using a bimetal, Hough used the difference in 

expansion of straight rods of iron and brass, and, 

while it is extremely ingenious, it could not possibly have worked for long outdoors. 

MHT 317,416. Mahogany box 49 x 17 x 14 cm, 

with a group of rods 39 cm long mounted along 

one side. There are six iron rods and five brass 

ones, each 0.23 cm in diameter. Their differential expansion is transmitted to an elaborate 

system of levers, chains, and a pulley, and there 

is also a complicated mechanism for moving a 

band of paper and making intermittent records, 

now far from complete. An experimental roll of 

paper was made up by pasting together strips, 

13.5 cm wide, cut from the New York Times of 

Monday, 12 March 1860. Presented by the 

Dudley Observatory in 1960. 

Next in date, and much more practical, is the 

bimetallic recording thermometer invented in 

1887 by Daniel Draper of Central Park Observatory, New York City (MHT 316,942, figure 

47).^^ This was the ancestor of millions of industrial instruments of all sorts, the flat circular 

chart having won the approbation of engineers, 

though not of meteorologists. This may in part 

be due to the great success of the recording 

^* Its external appearance is described by William Barton, 

Memoirs oj the Lije oj David Rittenhouse CPhiladelphia, 1813), 

p. 155, note. 

95 Lambert, Pyrometrie oder vom Maase des Feuers und der 

Wdrme (Bcdin, 1779), p. 124. Lambert had died in 1777. 

9s Middleton, op. cit. (footnote 64), chapter 9. 

97 Scientific Instruments by Henry J. Green, Successor to J. & 

H. J. Green, Manufacturer oj Meteorological and Scientific 

Instruments . . . 771 Broadway, Cor. Ninth St., New Tork, 

1887, p. 39. 

50 
FIGURE 47 

M H T 316,942. Daniel Draper's bimetallic 

thermograph. Height 35 cm. The cast frame is 

marked "Draper Self Recording Thermometer 

Patented 1887 Made for Henry J. Green 771 

Broadway, NY. " Draper received U.S. Patent 

369,170, issued 30 August 1887. It can best be 

described in the words of Green's catalog: 

"Consists of a bimetallic thermometer in a case, 

together with a clock, which carries a disc, with 

a chart upon its axle, instead of hands like the 

ordinary clock. The very slightest variation or 

fluctuation in temperature causes motion in the 

thermometer, which is most completely and 

effectively communicated to a lever, the long 

arm of which carries a pen, with the point resting 

upon the chart on the face of the disk. The clock 

needs to be wound, the chart changed and the 

pen supplied with ink prepared for the purpose, 

once each week." The bimetal is missing. The 

dial is 23 cm in diameter. Presented by the Lick 

Observatory in 1960. (Smithsonian photo 

61830.) 

FIGURE 48 

M H T 252,980. Early Richard thermograph. 

The weekly drum 9.3 cm diameter and 9 cm 

long carries a chart graduated from —30 to 

+ 110 [°F], with the days of the week in English. The brass baseplate, 21 x 8.6 cm, carries 

the Richard Freres trademark (an early version) 

and the number "143. " A curved Bourdon 

tube 10 x 2 cm operates the pen, now missing, 

through a link and lever. The outer case, 22 x 

12 cm X 16 cm high, is of japanned iron, with 

one glass window and two circular apertures 

covered with netting. The Bourdon tube is inside the case. Transferred from the U.S. Geological Survey in 1909. (Smithsonian photo 

61829-D.) 

instruments of Richar d Freres, in which the 

record is mad e on a dru m turne d by a clock 

inside it.^^ Th e Museum has several of their 

thermographs. 

T h e earlier type,«« of which MH T 252,980 is 

a n example , is shown in figure 48. Later, recognizing tha t the case would protect the Bourdon 

tube from rapid changes of temperature , Richar d 

Freres pu t the tube outside, ^°° with the residt 

shown in figure 49, which is a photograp h of 

M H T 327,713. This construction was later copied 

by the Friez firm, with certain additions. Th e 

98 See also p. 29. 

99 Richard Freres, Notice sur les instruments enregistreurs 

(Paris, 1886), pp. 8-9. 

100 Ibid., pp. 18-19. 

51 
FIGURE 49 

MHT 327,713. Richard Freres Bourdon-tube 

thermograph. It differs from MHT 252,980 in 

that the Bourdon tube is now outside the case, 

the base and one end of which are of cast iron, 

the top of japanned metal. The case is 23 x 

12.5 cm X 17 cm high, and has a large glazed 

window. The instrument is 34 cm long overall; 

the curved Bourdon tube, entirely unprotected, 

is 7 cm long and 3.3 cm wide. The base is 

marked with the Richard Freres' later trademark and the number "39990," also "Made in 

France." Transferred from the U.S. Naval 

Observatory in 1966. (Smithsonian photo 

61832-D.) 

Museum has two of these under the number 

M H T 308,177, one of which is shown in figure 

50. 

Instead of making the Bourdon tube record 

directiy on a drum, the Richard firm saw that 

it could be used with an electromechanical 

servo mechanism to indicate or record, or both, 

at any reasonable distance.^°^ The general principle of this is to have two insulated contacts, 

one on each side of the pointer of the thermometer—or indeed of any other instrument— 

not quite touching it, with two electromagnets 

arranged to move the pair of contacts in an 

appropriate direction to break whichever circuit is made by any movement of the pointer. 

At the same time, an indicating or recording 

FIGURE 50 

101 Ibid., pp. 71-73. 

52 

MHT 308,177. Bourdon-tube thermograph. Of 

the two in the Museum, one is lacking its cover. 

Very similar to MHT 327,713, but witii the 

base extended below the tube to give it some 

protection, and with a scale graduated from 5 

to 100° F, the pointed end of the pen arm 

acting as an index. Each is marked on the 

base "Thermograph, Type ML 18, Serial 114 

[and 129 respectively] Signal Corps U.S. Army, 

Order 110,445 Date 6-26-23." The cover of 

one specimen is marked "Julien P. Friez & 

Sons Belfort Meteorological Observatory 1230 

E. Baltimore Street Baltimore, Md. U.S.A." 

Transferred from the Signal Corps in 1923. 

(Smithsonian photo 61832-B.) 

mechanism at a distance is given a pulse of current that moves a pointer and/or a pen to the 

same extent, and in the same direction, as the 

two contacts moved in the transmitting apparatus. The Museum has a receiving instrument, 

M H T 316,815, that both indicates on a dial 

and records on a drum, and also a transmitter, 

M H T 314,564, with a Bourdon-tube thermometer. The two are shown in figure 51. 

Somewhat later than the Bourdon tube, the 

bimetal was applied to a simple recording thermometer, with the advantage of faster response. 
FIGURE 51 

Receiving instrument and transmitter. 

MHT 316,815. Receiving portion of the telethermograph. The 19-cm dial is marked 

"Tele-thermograph Brevete S.G.D.G. Jules 

Richard Paris Fahrenheit," and is graduated 

from 0° to 90°. In the upper part of the instrument there is a pen arm coupled to the 

mechanism that drives the pointer in front of the 

dial, and also a recording drum of the standard 

Richard type. Overall dimensions, 34 x 25 x 52 

cm. Transferred from the Weather Bureau in 

1959, 

MHT 314,564. Transmitting portion of a 

Richard Freres telethermograph. This consists 

of the mechanical parts of a standard Richard 

thermograph with a Bourdon tube 7 cm long 

and 3.2 cm wide, but instead of a pen arm 

there is a rod ending in a contact spring. The 

remainder of the mechani.sm, including electromagnets and ratchet arrangement, is in a 

black metal box 18.5 cm in diameter and 5 

cm deep. Overall dimensions, 34 x 26 x 16 cm. 

Transferred from the Weather Bureau in 

1954. (Smithsonian photo 61903-G.) 

53 
FIGURE 52 

MHT 317,478. Negretti and Zambra's "recording thermometer," A 

U-shaped thermometer on an ebonite base 25 X 3.4 X 0.6 cm. Cylindrical bulb; tube with constriction 

near bulb, next a tube graduated 

0 to 125 [°F], then a U bend. 

Beyond the bend the tube has a 

finer bore and is graduated 15 to 

120. The numbers for both scales 

and the legend "Negretti & Zambra's Patent" are on a piece of 

white-flashed glass 17 x 1.2 x 0.2 

cm lying between the branches of 

the tube. The tube is marked 

"Patent no. 28" and the base 

"Negretti & Zambra London" and 

"Recording Thermometer." It is to 

be installed vertical, bulb down. 

The temperature at any time can 

be indicated for future reference by 

simply rotating the thermometer 

one revolution counterclockwise, 

when the thread of mercury will 

break off and run into the second 

tube. It is reset by giving it one 

turn clockwise. A brass shaft, 1.5 x 

0.5 cm, projects from the back of 

the mounting. Transferred from 

the Weather Bureau in 1960. (Smithsonian photo 61900-B.) 

The Museum has a specimen from which the 

manufacturer's nameplate has been lost (MH T 

317,484). 

MHT 317,484. Bimetallic thermograph. A pen 

arm is mounted on a gate attached directly to 

the axis of a helical bimetal of 5 turns, 2.8 cm 

in diameter. The pen records on a standard 

drum 9.3 cm in diameter and 9.2 cm high, containing a seven-day clock. The base and lefthand end are cast; the remainder of the case, 

18 X 13 X 16 cm, is of sheet metal with a glazed 

window in front. The nameplate is missing, but 

the instrument is similar to those made by Short 

and Mason in England. Transferred from the 

Weather Bureau in 1960. 

We shall end with a reference to a thermometer that can be made to indicate the temperature that prevailed at the instant when it was 

rotated counterclockwise through one revolution 

in its own plane. ^°^ One of two examples in the 

Museum is MH T 317,478, shown in figure 52. 

This was originally conceived as a deep-sea 

thermometer. Negretti and Zambra's suggestion 

for its application to meteorology is shown in 

figure 53, which shows eight of these thermometers arranged to be released by a clock at 

3-hour intervals. 

102 Negretti & ^ambrds Encyclopaedic . . . Rejerence Catalogue . . . (London, n.d., but ca. 1886), pp. 101-3. 

NEGRETTI AND ZAMBRA'S PATENT APPARATUS FOR RECORDING HOURLY TEMPERATURES. 

FIGURE 53 

Array of eight thermometers to record the temperature at three-hour intervals. 

(Smithsonian photo 63210.) 

54 
Instruments not Referred to in the Text 

Like man y othe r museums, the Museum of 

History an d Technology contains a disproportionate numbe r of thermometers in its meteorological collection. Man y of these differ only in 

unimportan t respects from instruments tha t have 

been described above, an d to avoid unbalancin g 

t h e catalog, these will hav e only brief reference 

here . 

230.005. Maximum thermometer on metal mount 

marked "H . J. Green B'klyn. N.Y. N" 9746 U.S. 

Weather Bureau." Length 31 cm. Transferred from 

the Weather Bureau in 1904. 

230.006. Minimum thermometer, Rutherford type, on 

metal mount, marked "H. J. Green B'klyn. N.Y. N° 

7390 U.S. Weather Bureau Minimum. " Length 31 cm. 

Transferred from the Weather Bureau in 1904. 

308.156. Household thermometer with red spirit and 

lens front to make the spirit column look wider. Tube 

mounted on silvered-brass plate carrying scale, —20 

to +116 ° F in 2-degree intervals. "Freezing" opposite 

32, "Temperate " opposite 56, "Sumr Heat" opposite 

.76, and "Blood Heat " opposite 98. Brass guard for 

spherical bulb. All on varnished oak base 22 x 5.2 x 0.9 

cm with hanging ring. Plate marked "Taylor Bro's 

Rochester N.Y. " and trademark. Presented by the 

Taylor Instrument Companies. 

308.157. Household spirit thermometer, similar to 

308,156 except for color of mount and extent of scale, 

marked "Tycos Rochester, N.Y. U.S.A. Toronto, 

Canada." 

308.196. Mercury-in-glass thermometer, with a cylindrical bulb (blown from the tube, which has a white 

glass strip). Scale —10 to +6 8 [°C]. Tube marked 

"EtabP^ Poulenc Fils Paris." Length 17 cm. Apparentiy used during World War I by the Meteorological 

Service of the American Expeditionary Forces. Transferred by the Signal Corps in 1923. 

308.197. Mercury-in-glass thermometer, on a metal base 

24 X 2.3 X 0.2 cm, formed with a groove, and marked 

"Schneider Bros N° 7293." The scale, -3 5 to +13 0 °F, 

is marked on the tube, the numbers and the major 

divisions repeated on the base. Transferred from the 

Signal Corps in 1923. 

308,199. Maximum and minimum thermometers on 

Townsend support, similar to 308,198 except that the 

thermometers are numbered 36061 and 41530 respectively. Transferred from the Signal Corps in 1923. 

314,534. "Kiosk" thermometer, mercury-in-glass, last 

10 cm bent backwards and going through a hole in 

the metal plate, which measures 40 x 5 cm. Cylindrical bulb 4.5 x 1.0 cm. Bears the Number "U.S. 

No. 2," but in other details is the same as MH T 

314,533. Transferred from the Weather Bureau in 

1954. 

314.554. Exactly the same as MH T 317,478, except 

that the brass bearing is missing, and the tube is 

marked "Negretti & Zambra's Patent, 62. " Trans 

ferred from the Weather Bureau in 1954. 

314.555. Alcohol-in-glass thermometer, with its tube, 

graduated from —70 to +113 [° F], mounted on a 

silvered (much corroded) flat metal plate 20 x 2.4 

x 0.15 cm. The cylindrical bulb and 1 cm of the tube 

project below the plate. Numbers and main divisions 

on white glass strip beside tube. Tube marked "U.S. 

2352." Plate marked "H. J. Green N.Y. No. 2352 

Signal Service U.S. Army." Transferred from the 

Weather Bureau in 1954. 

314,557. Mercury-in-glass thermometer for measuring 

temperatures near the surface of water. A mercury 

thermometer, graduated on the stem from 21 to 50° F 

in fifths, is suspended in a mounting of wood and 

brass, the lower part of which forms a cup 4 cm long 

and 2.5 cm diameter, surrounding the bulb. A 

helical spring has one end attached to the bottom of 

this cup as a shock absorber. At the top end the 

mounting is completed by a brass ferrule and hanging 

ring. Total length 29.5 cm. Transferred from the 

Weather Bureau in 1954. 

314,870. Pair of thermometers, maximum and minimum, each on a metal back 31 x 2.2 cm, the whole 

mounted on a mahogany board 34 x 9 x 1.3 cm, the 

spherical bulbs covered with a protective metal 

strip. The maximum thermometer is marked "No. 

90162 Henry J. Green B'klyn. N.Y. Maximum." 

The minimum "Taylor Rochester, N.Y. No. [blank] 

Minimum" and on the stem "U.S. 242382". Deposited by the Smithsonian Astrophysical Observatory 

in 1956. 

55 
315,808. She small resistance-thermometer elements 

in steel casings with plastic terminal boxes, overall 

lengths 10 and 7.5 cm; also a vial containing the 

disassembled elements of a seventh instrument. These 

thermometers, developed by George F. Taylor for 

micrometeorological studies, were patented (U.S. 

Patent 1,490,990) and described in the Physical Review, vol. 26 (1924) pp. 841-50. "Each element consists of a lead filament 1.5 cm long and 2 x 10"^ mm 

in diameter in a glass tube 4 x 10~^ mm thick, embedded in a type metal which makes contact with 

one end of the filament. . . . The resistance of the 

filament is 448 ohms so that with a portable galvanometer a sensitivity of .005° is readily obtained. 

The temperature lag is about 10 sec."^"^ Presented in 

1958 by Mr George F. Taylor of Grosse Point Woods, 

Michigan. 

315.811. Alcohol-in-glass thermometer 31 cm long 

with a tube having a white glass back. Graduated in 

half degrees from [—] 80 to 0. Marked "Henry J. 

Green, B'klyn, N.Y. No. 8067." Deposited by the 

Smithsonian Astrophysical Observatory in 1958. 

315.812. Mercury thermometer 30 cm long with a 

spherical bulb and a scale, not numbered, but having 

85 divisions. The tube bears the number 89,593, but 

is unsigned. It is evidendy intended for use on a 

mount bearing the numbers. Deposited by the 

Smithsonian Astrophysical Observatory in 1958. 

316,003. Mercury-in-glass thermometer with a blackened bulb, 1.0 cm diameter, and a tube with milkglass back, 35 cm long; scale in °C, 10° to 60° in 0.1° 

divisions. Marked "J. & H. J. Green, N.Y. No. 

4571." Deposited by the Smithsonian Astrophysical 

Observatory in 1958. 

316,009. Mercury-in-glass thermometer, graduated 

from -20. 0 to +74.8 [°C] in fifths, and bearing the 

legend "Tub . non Cyl. div. rectif. syst. Baudin 

(1881.3)." The bulb cannot be seen for it is inside a 

copper ball about 5 cm in diameter, with a roughly 

sealed glass tube projecting 7.5 cm in the direction 

opposite to the thermometer tube. Probably a research 

apparatus. Deposited by the Smithsonian Astrophysical Observatory in 1958. 

316,084. Alcohol-in-glass thermometer, minimum, 

Rutherford type, on flat brass mount 30.5 x 2.2 x 0.15 

cm, with hole 1.6 cm diameter beneath the 1.2 cm 

spherical bulb. Scale, -7 2 to +11 7 [°F], divided 

on the tube and numbered on a white-glass strip. 

The tube has a white-glass background. Bulb blown 

from clear glass. On the mount: "N° 7742 Henry J, 

Green B'klyn. N.Y." Deposited by the Smithsonian 

Astrophysical Observatory in 1959. 

Thermometers numbere d 316,155 to 316,286, inclusive, wer e transferred from the Weathe r 

Bureau in 1959. 

316,155. A wooden box 39 x 21 x 18 cm, containing 

thermometers filled with various liquids, used at 

Fort Conger on the Lady Franklin Bay polar expedition in 1881-83,^"* in order to determine the relative 

merits of alcohol, carbon disulphide, and ether at 

temperatures below —40° F. Six of the thermometers 

are Rutherford-type minimum thermometers of 

uniform pattern, about 42 cm long, with spherical 

bulbs 1.5 to 2.0 cm in diameter, blown from the 

tubes with their white-glass strips. The scales are 

engraved in millimeters on the tubes, and numbered 

on an adjacent brass scale, from 0 up to 250. Each 

has a Signal Service number: Numbers 2 and 4 are 

stated to be filled with ether, numbers 6 and 8 with 

carbon disulphide, and numbers 10 and 12 with ether. 

A typical inscription is: "J. & H. J. Green N.Y. 

Yale Min. Std. May 1881. Corning glass. Squibbs 

ether. Signal Service U.S. Army. N° 2. " Each is 

mounted in a hinged pine box 34 x 3 x 4 cm, with 

a hole to expose the bulb. Two ordinary spirit thermometers and the remains of another are attached 

to grooves in three sides of a wooden block; a fourth 

seems to have disappeared. All were made by J. & 

H. J. Green, and have flat metal mounts. One, 

Signal Service number 708, has a spherical bulb; 

another, number 1010, a cylindrical bulb. Number 

708 is graduated, on the mount only, from —73 to 

+ 132 [°F]; number 1010 from -6 7 to +123° . 

316,271. Transmitting apparatus, incomplete, of a 

telethermograph. By means of a linkage, sector, and 

103 Physical Review, vol. 26 (1924), p. 841. 

56 

104 See Adolphus W. Greely, Three Years oj Arctic Service. 

An account oj the Lady Franklin Bay Expedition oj 1881-84 . . . 

(New York, 1886), vol. 1, p. 125. "Some excellent standard 

thermometers, of bisulphide of carbon, pure spirits of 

wine, and ether, were made for the expedition, under the 

careful supervision of Professor Waldo of Yale College 

Observatory. They were graduated in millimetres 

arbitrarily. ... " 
pinion, a Bourdon tube moves a pointer which is 

bracketed by two contacts (missing) carried by a 

shaft driven by a reversing motor. The apparatus, 

made largely of brass, is covered by a copper case 

23 X 20 X 22 cm, and is on a mahogany base 24 x 22 

cm. The Bourdon tube, 7 x 3,3 cm, is freely exposed 

outside the case. On the case is the inscription 

"Tele-thermographe Brevete S.G.D.G. Jules Richard 

Constructeur Paris"; on the instrument, "Richard 

Freres Constructeurs brevetes Paris" and the trademark of the firm. (See also MH T 314,564, figure 51.) 

316.277. Two Russian enclosed-scale thermometers, 

each 36 cm long. The white-glass scale of one (number 

1087) is loose. Number 1087 is graduated in fifths 

from —12.0 to +39.0° C and number 1114 from 

— 11.0 to +37.0 ° C. Each marked with a monogram 

and "OCT 40172." 

316.278. Russian enclosed-scale thermometer, mercury-in-glass, 36 cm long and 1.7 cm in diameter. 

Milk-glass scale, held in glass at the bottom, and by 

a cork at the top. Graduated —35° to +84 ° C in 

half-degrees. Marked "4277" on front of scale and 

"OCT 40178" on back. 

316.279. Russian enclosed-scale mercury-in-glass thermometer, 42 cm long. Graduated in fifths, —32° 

to +43 ° C on white-glass scale. Bulb roughly spherical. 

Scale bears number "98 " and works mark "OCT 

40180." Outer tube has "538423" and a monogram 

etched on it. Heavy nickeled cap at end opposite 

bulb. 

316.280. Russian enclosed-scale thermometer, 42 cm 

long, similar to 316,279 except that the scale (which 

is broken) is graduated from —29 to +41 ° C. Numbered "153 " on scale and "538454" on tube. 

316.281. Russian enclosed-scale maximum thermometer, 34 cm long, with constriction. The enclosed 

milk-glass scale is broken. Scale in half-degrees G 

from —30 to +74° , Front of scale marked "MaKCHMajifcHHH and back "OCT 40177." 

316.282. A pair of Russian enclosed-scale thermometers, 39 cm long, graduated on white glass from 

—82 to +25 ° C, in half degrees. Cylindrical bulbs 

only about 1.8 x 0.6 cm filled with clear alcohol. 

Bear the numbers "327740" and "327800" etched 

on the outer tube. 

316.283. Russian enclosed-scale minimum thermometer, 35 cm long, Rutherford type, with slender 

black-glass index 1.2 cm long. Scale —56° to +22 ° 

C in half degrees. Marked "MnnHMaJitHtiH" 

and "693 " on front and "OCT 40179" on back. 

316.285. Russian sling thermometer, scale —31° C 

to +45 ° C in half-degrees on white-glass-backed 

tube, marked "N 958 FOCT 381-41. " 19 cm long, 

with cylindrical bulb. A string 60 cm long is attached 

to a glass knob at the end of the tube. The instrument is accompanied by a calibration sheet, a printed 

form. 

316.286. Two Russian enclosed-scale mercury-in-glass 

thermometers 22 cm long. The white-glass scale of 

one is broken. Each is graduated in fifths from 

-4. 6 to +41.0° C. They bear tiie numbers "5209" 

and "5229" on the scales, and "FOO T N 59-40" 

etched on the protecting tubes. 

316,450. Mercury-in-glass thermometer, 20 cm long, 

with a cylindrical bulb 3.8 cm long and 0.7 cm in 

diameter. The scale, intended for the measurement of 

the boiling point of water, and hence of the atmospheric pressure, is from 208 to 218° F in tenths of a 

degree. The tube has a white-glass back, marked 

"Palo Co. N.Y." 

316,452. Mercury-in-glass thermometer with a tube 

11 cm long and a spherical bulb 0.8 cm diameter, 

scale on a slip of ivory, 183° to 247° [F?]. Marked 

" J. Green N.Y." Transferred from the U.S. MUitary 

Academy in 1959. 

Thermometers numbere d 317,443 to 317,475 

inclusive wer e transferred from the Weathe r 

Bureau in 1960. Of these, numbers 317,443 to 

317,453 are thermometers tha t wer e most prob -

ably used as standards a t one time or anothe r for 

the calibration or testing of meteorological 

thermometers. 

317.443. Mercury-in-glass thermometer 31 cm long, 

having a cylindrical bulb 0.5 cm in diameter. The 

tube has a white-glass back strip, marked "J. & H. J. 

Green, N.Y. No. 734." The scale, -4 0 to +125 ° F, 

is etched on the tube. 

317.444. Mercury-in-glass thermometer 32 cm long, 

with a spherical bulb 0.8 cm in diameter, and a scale 

in half-degrees from —15.5 to +75 ° C etched on the 

tube, which has a white-glass strip and is marked 

" L. Golaz k Paris. Centigrade. 729." 

57 
317.445. Mercury-in-glass thermometer 38 cm long, 

with a cylindrical bulb. The scale, —25 to +130 ° F, 

is etched on the tube, which has a white-glass back 

strip, marked "L. Casella. London. 14490." 

317.446. Almost exactly like MH T 317,444 above, 

except that it bears the number "725 " and that the 

scale is graduated from —14 to +69 ° C. 

317.447. Mercury-in-glass thermometer 63 cm long 

with a cylindrical bulb. The scale, in fifths of a degree 

from —15 to +4 1 [° C] is etched on the tube, which 

has a white-glass strip. Calibration marks at 0° and 

36.08°. Marked "J. Hicks. 8 Hatton Garden, London. 

207446." 

317.448. Mercury-in-glass thermometer 46 cm long 

with a cylindrical bulb. The scale, —40 to +140 ° F, 

is etched on the tube, which has a white-glass strip. 

Marked "Hicks' Patent No. 4434," and "J. Hicks, 

8 Hatton Garden London. N? 217122." In brass case. 

317.449. Mercury-in-glass thermometer 64 cm long, 

with a clear-glass tube less than 0.5 cm in diameter, 

and a cylindrical bulb. Scale in fifths of a degree from 

— 10.2 to +108.0 [°C]. Red graduations and figures. 

Marked "Tonnelot a Paris. (1884.5) 4289." 

317.450. Spirit-in-glass thermometer 52 cm long, 

having a cylindrical bulb 5 x 0.8 cm, and a tube with 

a white glass strip. Scale, —65 to +150 ° F, etched on 

tube. Marked "J. Hicks 8 Hatton Garden London, 

—N° 217967—." 

317.453. Spirit-in-glass thermometer 51 cm long, 

having a cylindrical bulb; scale in fifths of a degree, 

— 70 to +30 ° C, etched on tube with milk-glass 

strip. Marked "Thermometre Baudin No. 15774 

gradue d'apres I'Echelle Normale Internationale 

(1902.9)." Large safety bulb at top of tube. 

317.454. Mercury-in-glass thermometer 26 cm long. 

Enclosed rolled-paper scale, —16 to +60° C. Cylindrical bulb. Marked on paper scale "No. 6563 U. S. 

W. B. Phila. Thermo. Co." 

317,458. Mercury-in-glass thermometer 17 cm long; 

cylindrical bulb 0.5 cm diameter, tube with milkglass strip, bulb blown directly from this; scale —32° 

to +43° . Marked "Centigrade, 699. J. Salleron, 

24 rue Pavee (au Marais) Paris." 

317,460. Minimum thermometer of the Rutherford 

type, 26 cm long; spherical bulb 1.8 cm in diameter. 

Tube with milk-glass strip, with the scale etched on 

it, —68° to +127 ° [F]. The bulb blown directiy 

from the tube, with the strip. No other markings. 

317.462. Minimum thermometer of the Rutherford 

type, with very small cylindrical bulb, only about 

1.9 X 0.5 cm, and very fine tube and dumbbell.index. 

Length 29 cm, bulb projecting 3.5 cm beyond metal 

mounting with formed groove. Scale —39 to +11 0 

[°F] on tube, numbers and major divisions repeated 

on mounting. Tube marked "U.S. 8727." Mounting 

marked "H . J. Green B'klyn. N.Y. N? 8727 U.S. 

Weather Bureau" and "Minimum. " 

317.463. Spirit-in-glass minimum thermometer, 

length 30 cm. The bulb, 4.5 x 0.5 cm, projects 5.5 cm 

beyond the flat brass mounting, 24 x 2.3 x 0.15 cm. 

It is a minimum thermometer with a conical frustum 

5.5 cm long, the larger end farther from the bulb, the 

"tail " very narrow, behind the usual dumbbell-shaped 

index. Scale, —92 to +9 7 [°F] on the tube, with 

numbers and major divisions on an adjacent whiteglass slip. Tube marked "No . 1868 Signal Service 

U.S. Army." On the mounting "1868 Henry J. 

Green New York." 

317.464. Thermometer similar to 317,463 except that 

the metal mounting is extended, with an oval cutout, 

past the bulb. Scale —90 to +8 0 [°F]. Markings: on 

tube, "No. 1924 Signal Service, U.S. Army" ; on 

mounting, "1924 Henry J. Green New York." 

317.465. Minimum thermometer of the Rutherfordtype on a flat brass mount 30 x 2.3 x 0.15 cm. Scale 

graduated on tube and numbered in tens on adjacent 

strip of white glass, —35 to +12 2 [°F]. Tube marked 

"U.S. 1483." Mounting engraved "N° 1483 Signal 

Service U.S. Army. JA« Green New York." The bulb 

of this thermometer, 1.1 cm in diameter, was blown 

from the tube, with its white-glass strip. 

317.467. Minimum thermometer of the Rutherford 

type, 30 cm long, with a spherical bulb 1.6 cm in 

diameter; scale —95 to +135 ° [F] on the tube, which 

has a milk-glass strip. Marked "J. & H, J. Green, 

N.Y. Signal Service U.S. Army No. 14." Probably 

had a base, now missing. 

317.468. Minimum thermometer of the Rutherford 

type, 26 cm long. The scale, from —40 to +100 ° F 

is engraved on the tube, which has a white-glass back 

strip. No other markings. The liquid with which it is 

filled is slightly yellow. This has almost certainly had 

a mounting at some time. 

58 
317.469. Minimum thermometer of the Rutherford 

type, 32 cm long, scale —20 to +13 0 [°F]. Dumbbell 

index 1.5 cm long. Cylindrical bulb. Scale etched on 

tube, which has milk-glass insert. Marked "Patent 

N° 4434 [Kew Observatory monogram] 10085 

N« 84120." 

317.470. Minimum thermometer of the Rutherford 

type, 30 cm long, with 1.9 cm spherical bulb. Scale, 

—22 to +11 2 [°F] etched on tube, numbers and main 

divisions on white porcelain plate 24 x 3.7 cm, 

surrounded by heavy mahogany frame, with 2 hanging 

rings and brass guard for bulb. Porcelain plate 

inscribed "M.O. [monogram] 24 Negretti & Zambra, 

Scientific Inst* Makers, London" and N & Z monogram. Overall length, 34.5 cm. 

317.471. Spirit-in-glass minimum thermometer, almost identical with 317,470, except that it is marked 

"M.O. [monogram] 575 J. Hicks, 8, 9, & 10. Hatton 

Garden London." 

317.472. Maximum thermometer with constriction; 26 

cm long; cylindrical bulb; scale 0-100° F engraved 

on glass tube with milk-glass strip. Marked "Maximum Phila. Thermo. Go. 31507," 

317.473. Maximim thermorneter to U.S. Weather 

Bureau specification. Similar to 317,474 below, except 

that the scale goes from —30 to +11 0 [°F]; the tube 

is marked "US 43191" ; and the mounting "Taylor 

Rochester N.Y. U.S.W.B. No. 43191 Maximum." 

317.474. Maximum thermometer with constricted 

tube, mounted on metal (stainless steel?) plate 30.4 

X 2.3 X 0.2 cm, with formed groove. Spherical bulb, 

1.2 cm in diameter. Scale on tube —29 to +5 7 

[°C?]; major divisions and numbers also on mounting. 

Tube marked "U.S. 12701." Mounting marked "H. J. 

Green B'klyn. N.Y, N? 12701 U.S. Weather Bureau. 

Maximum. " Bearing, brass, for about 0.5 cm, shaft 

is screwed to mounting at end remote from bulb. 

317.475. Maximum thermometer, 30 cm long, with 

constriction, in a wooden frame with white porcelain 

plate behind the tube, and a brass guard for the 

cylindrical bulb. Scale on tube, from —50 to +12 5 

[°F]; figures and main divisions on porcelain plate, 

which carries the notation "B 22580 Negretti & 

Zambra, London" and their monogram, 

322,607. A minimum thermometer of the Rutherford 

type, made by "Dr H Geissler in Bonn." It is an 

enclosed-scale thermometer with a milk-glass scale 

inside a glass tube 2 cm in diameter. The total length 

including the brass cap is 42 cm. It is graduated in 

fifths of a degree C from —39 to +49° . The bulb is 

forked, with two prongs each 4 cm long and 7 mm 

diameter. Presented by Western Reserve University 

in 1963. 

322,751. Reproduction of the famous helical thermometer described in the Saggi and existing in the 

Museo di Storia della Scienza at Florence. Overall height 

35 cm, diameter 11 cm. Received in 1963. 

322,754. Reproduction of the thermoscope traditionally ascribed to Galileo. Identical with MH T 

322,752 (figure 30). 

322,764. Mercury-in-glass thermometer with spherical bulb 1.0 cm in diameter, painted black. The tube 

has a white-glass back, and is marked "Tu b non cyl 

div. rectif. syst. Baudin (1881.8) Centigrade 9014," 

The scale is from —20.0° to 70.4° C m fifths. The 

instrument is 36 cm long, and is in a cylindrical brass 

case. Provenance unknown. 

326,555. Maximum thermometer of the Phillips type, 

two small air bubbles near bulb. Thermometer 30 cm 

long, with spherical bulb, mounted on a porcelain 

base 29 x 4.3 x 0.5 cm, the whole on an oak base 

35 X 5.5 X 1.3 cm, with a hole behind the bulb and a 

semicircular brass guard over it. Scale on tube, — 4 to 

+12 7 [° F]; figures on porcelain base, which is marked 

"Maximum L. Casella. Maker to the Admiralty, 

London N° 9714." Provenance unknown. 

326,942. Simplified Six's maximum-and-minimum 

thermometer in a black molded-plastic frame 29 cm 

long and 6 cm wide, the actual tube being attached to 

a blackened metal plate bearing white numbers and 

the main graduations, as well as the words "Cold," 

"Heat, " and "Taylor Rochester, N.Y. U.S.A." The 

maximum graduated from —10 to +13 0 [° F], the 

minimum from —40 to +110, on the lens-fronted 

tube. Transferred from the District of Columbia Public Schools in 1965. 

327,549. Minimum thermometer of the Rutherford 

type, with its tube bent down near the spherical bulb, 

mounted in a wooden frame with two rings for hanging. In this is set a white-glass plate 18 x 5 cm 

bearing the scale, —35 to +50 ° C, and the inscription 

"Thermometer minima nach Celsius." Overall length, 

29 cm. Presented in 1966 by Union College, 

Schenectady, New York. 

59 

209^40 0^69-
FIGURE 54 

MHT 316,858. Reproduction of the oat-beard 

hygrometer, about 10 cm square and 5 cm high, 

based on the illustration in the Micrographia of 

Robert Hooke. In this instrument the pointer 

also carries a small vertical appendage projecting downward that engages the teeth of a star 

wheel and counts the number of revolutions 

made by the pointer. Marked "Eichner Fecit 

MCMLIX." Received in 1959. (Smithsonian 

photo 61901-A.) 

FIGURE 55 

MHT 314,542. A 19th-century copy, fairly close 

in general appearance, of H. B. de Saussure's 

original hair hygrometer, second model; instead of a weight to keep the hair extended, this 

has a fine hairspring. The frame, 32.5 x 9.4 cm, 

is rather elaborately supported in a mahogany 

box, 40 X 17 X- 11 cm, of which the glazed 

front and the two longer sides can be opened on 

hinges. The pointer moves over a silver quadrant 

fastened by three screws to a brass plate, but the 

scale, 0 to 100, is engraved on the latter. There 

is no maker's name. Transferred from the 

Weather Bureau in 1954, (Smithsonian photo 

61901-B,) 

60 
Chapter 4 

Instruments fi^r the Measurement 

Of Atmospheric Humidity 

The measurement of the amount of water 

vapor in the atmosphere can be made in several 

distinct ways, so that there are at least six classes 

of instruments that might appear in this chapter. 

Three of these are represented in the collection: 

• Those depending on the absorption of water 

vapor by solid substances, 

• Those making use of the condensation of 

water on a cooled surface. 

• Those depending on the cooling produced 

by the evaporation of water. 

There are also chemical, electrical, and optical 

hygrometers, of which only the electrical, which 

will be mentioned in chapter 10, have been 

used to any extent in meteorology. 

Absorption hygrometers 

It occurred to both Leon Battista Alberti ^°^ 

and Nicolaus of Cues "* in the 15th century that 

if some water-absorbing substance was placed 

"* Alberti, De re aedificatoria (Florence, 1485), Book 10, 

chapter 3, 

iM Nicolaus [Khrypffs] of Cues, Opera (Basle, 1565), 

p. 176, This was written about 1450. 

on one end of a balance beam, the balance 

would vary its equilibrium as its load absorbed 

more or less water from the atmosphere. Alberti 

used a sponge; Nicolaus used wool. 

In the succeeding centuries, the changes in 

dimensions of various organic substances came 

to be preferred to changes in weight. By 1554 

Antoine Mizauld related the change in the 

length of gut strings to the changes in the air."^ 

Dozens of hygroscopes, many of them fantastic, 

were described in the 17th and 18th centuries, 

making use of various animal and vegetable 

substances and even porous stone, ^°^ Of all those 

invented before about 1780, the best known is 

the "oat-beard hygrometer" usually ascribed 

to Robert Hooke, but certainly known to 

Emmanuel Maignan in 1648.^°' Hooke's instruw" (Paris, 1554) Mizauld, Ephemerides aeris perpetuae 

p, 49. 

i»8 Some account of these will be found in W. E. K. 

Middleton, The invention oj the meteorological instruments 

(Baltimore: The Johns Hopkins Press, 1968), pp. 85-102. 

>TM Maignan to Prince Leopold of Tuscany, from Rome, 

July 18, 1648. Florence, Bibl. Naz., ms. Gal. 275, fol. 16. 

61 
FIGURE 56 

MHT 314,527. Lambrecht's hair hygrometer. In 

a brass case 13.5 cm in diameter and 4.2 cm 

thick, with many perforations round the sides, 

is mounted a bundle of hairs attached to a 

weighted lever arm on an axis which carries a 

pointer moving in front of a scale graduated 

non-uniformly from 0 percent to 100 percent 

(relative humidity). The white card that carries 

the scale is printed with the monogram of 

Wilhelm Lambrecht and also "U.S. W.B. 87, 

Lambrecht's Hygrometer, Percentage of Humidity," Transferred from the Weather Bureau 

in 1954, (Smithsonian photo 61900-C.) 

ment "° has an elementary revolution counter, 

as in the reproduction (MHT 316,858) shown in 

figure 54, because the awn of the wild 

oat seed could make several turns. 

The only absorption hygrometer that has had 

wide use in meteorology is the hair hygrometer, 

first described in 1783 by Horace Benedict de 

Saussure (1740-1799) of Geneva.^i^ The Museum 

has a 19th-century hair hygrometer (MH T 

314,542) that looks very like De Saussure's 

original smaller model, and is shown in figure 55. 

Many modifications of the original models have 

been made, some in De Saussure's lifetime. One 

modification was to use bundles of hair, as in 

M H T 314,528, it being felt that tiie single hair 

was too fragile; or "harps " in which several 

hairs were kept parallel by being attached to a 

wide clamp at each end (MH T 314,536). Both 

these schemes are stronger than the single hair, 

but raise the difficulty of ensuring that all the 

hairs are under the same small tension. 

MHT 314,528. Hygrometer, designed by Professor C. F. Marvin in 1908, which adds the changes 

of length of two bundles of hair, each 16 cm 

long. These are carried in a housing formed b y 

four rods, extending behind a flat cylindrical 

brass box 15 cm diameter x 2.5 cm thick, 

having a glass front which shows the pointer 

and a silvered scale reading 0 to 100 and marked 

"Percentage of saturation [relative humidity] 

Hair Hygrometer N? 19 U.S. Weather Bureau, 

Henry J, Green, B'klyn, N.Y," Transferred 

from the Weather Bureau in 1954, 

MHT 314,536. Hair hygrometer with two 

"harps" of hair each 17 cm long (one now 

broken), their changes in length added by a lever 

at the top, and communicated to the pointer 

shaft by a lever of adjustable length. Scale covering an arc of about 60 degrees, graduated 0 to 

100, Frame marked "U.S, Weather Bureau. 

N° 22 H. J. Green B'klyn. N.Y." Transferred 

from the Weather Bureau in 1954. 

In the last decades of the 19th century, 

Wilhelm Lambrecht made large numbers of 

simple hair hygrometers—especially for household use—of which MH T 314,527, figure 56, is 

an example. He also combined it with a liquidin-glass thermometer, calling the result a "Polymeter," because the dew point and the vapor 

pressure could be derived from the results."'^ 

"" Micrographia . . . (London, 1665), pp. 149-51. 

'" De Saussure, Essais sur I'hygrometrie (Neuchatel 1783). 

"2 See Julien P. Friez, Illustrated Catalogue oj Meteorological 

Instruments and Apparatus . . . (Baltimore, 1893), pp. 35-37. 

62 
FIGURE 57 

MHT 316,597. Draper's hair hygrograph. It 

records on a flat circular chart, 31 cm in diameter, revolved once in seven days by a clock. 

Inside the case, a flat bundle of hairs passes 

partly round a brass cylindrical sector on the 

same shaft as a pen arm, A small weight keeps 

the hairs extended. On the cast front of the case 

is the legend "Draper's Self-recording Hygrometer Pat, Appld for. The Draper Mfg. Co. 152 

Front St. N.Y." Deposited by the Freer Gallery 

of Art in 1959. (Smithsonian photo 61907-D.) 

The Museum has an incomplete example (MHT 

314,562). 

MHT 314,562. Hair hygrometer in a form widely 

distributed by Wilhelm Lambrecht of Gottingen; damaged and incomplete. A frame of two 

brass plates 24 x 2 cm, spaced 0.7 cm apart, 

held a bundle of hairs, now missing. Near the 

.^ 

FIGURE S8 

MHT 327,634. Hair hygrograph similar to those 

tmder MHT 308,178, but in mint condition. 

The cover bears the label "Hygrograph SOFNJ 

No. 2133 Julien P, Friez & Sons Baltimore Md. 

U.S.A." It is finished in glossy dark-brown 

enamel, the mechanical parts are of lacquered 

brass. Presented in 1966 by Rutgers University, 

New Brunswick, New Jersey, (Smithsonian 

photo 61907-B.) 

bottom of the frame is a brass box 7.5 cm in 

diameter x 1.2 cm thick, with a glass front and 

a white dial. The dial carries scales of relative 

humidity and depression of the dew point, also 

instructions for the (very approximate) determination of the dew point, and is marked 

"Julien P. Friez Meteorological Jnstruments 

\sic\ and Apparatus Baltimore (Md.) U.S,A. 

Lambrecht's Polymeter," There are clips to 

hold a thermometer, which is missing. Transferred from the Weather Bureau in 1954, 

The hair hygrometer lends itself to making a 

record. Probably the earliest hair hygrograph in 

the collection is that designed about 1887 by 

Daniel Draper, at one time director of the Central 

Park Observatory in New York City.' This is 

M H T 316,597, and is shown in figure 57. 

63 
A more sophisticated approach was taken by 

Richard Freres of Paris, who added a hair 

hygrograph to their line after experimenting 

with goldbeater's skin and with horn. This firm 

believed it to be important to have a linear scale 

of relative humidity, and achieved this result by 

means of two cams, at the expense of some frictional resistance. The Richard Freres design was 

later made in the United States by Julien Friez, 

and the Museum has three of these, two under 

the number MH T 308,178, 

MHT 308,178. Two hair hygrographs, neither 

quite complete. These are of the type in which 

the bundle of hair, 19 cm long, is mounted 

transversely to the plane of the lever system, 

and a system of cams is used to make the scale 

linear in relative humidity. A drum, 9,2 cm 

diameter x 9.5 cm long, contains a clock, and 

has a weekly chart. The base, 23 x 13 cm, and 

right-hand end of the instrument are of cast 

iron. The cover, 22 x 12 x 13 cm, hinged to 

the base, is of sheet metal with a glass front and 

a brass carrying handle. On the cover, "Julien 

P, Friez & Sons Belfort Meteorological Observatory 1230 E. Baltimore Street, Baltimore, Md., 

U.S.A." On the base, "Hygrograph Type ML 

16 Serial 74865 [on both instruments!] Order 

110418 Date 2.8.23", Transferred from the 

Signal Corps in 1923. 

A third, in mint condition, is illustrated in figure 

58 (MHT 327,634), 

Goldbeater's skin has certain advantages over 

hair as a material for hygrometers, especially a 

faster response at low temperatures, though it 

has not been much used except for upper-air 

observations in some countries. The Museum has 

a somewhat damaged hygrograph MH T 317,486, 

which seems to be an experiment in using goldbeater's skin for this purpose, 

MHT 317,486. Hygrograph which appears to 

have been modified from a standard instrument 

("Henry J. Green B'klyn. N.Y. N? 1039 Type 

615 U.S. W. B. N°. 67," according to the nameplate on the cast-iron base) by substituting for 

the hair two aluminum rings 5 cm in diameter, 

between which a sheet of goldbeater's skin (now 

ruptured) is clamped. The center of this sheet 

was cemented to two disks of bakelite, 0.95 cm 

diameter, attached by a light chain to a lever 

arm of adjustable length fastened to the axis of 

the pen arm. The base and case are of the usual 

standard design and size (see MHT 308,178) 

adopted by the Signal Corps and the Weather 

Bureau. Transferred from the Weather Bureau 

in 1960. 

Condensation hygrometers 

Not content with inventing the spirit-in-glass 

thermometer,"3 Ferdinand II of Tuscany also 

invented a condensation hygrometer, the first of 

its kind. In this instrument the humidity of the 

air was measured by noting how much condensed 

water per hour ran oflf the tip of a conical vessel 

filled with ice or snow. The date was about 

1655."* An elegant instrument was developed,"^ 

of which the Museum has a modern replica 

(MHT 319,467, figure 59). However, this way 

of measuring humidity was time-consuming and 

probably very sensitive to the speed of the air 

past the cone; at all events the Grand Duke's 

instrument seems to have had no successors. 

Nearly a century later, while investigating dew 

at Montpelier, G. Le Roy introduced the concept of the dew point, which he called degre de 

saturation "*—the temperature to which a surface 

has to fall before visible dew begins to condense 

on it. This is a single-valued function of the 

amount of moisture in a given volume of the air. 

The subsequent history of the dew-point hygrometer consists of attempts to provide controllable cooling of a surface and to standardize 

the conditions of observation. 

The most usual means of cooling the surface 

in the 19th century was by the evaporation of 

ether. In the well-known hygrometer of J, F. 

Daniell"^ (figure 60) the glass tube and bulbs 

"3 See p, 38. 

"* The earliest sketch of such an apparatus is probably 

in Florence, Bibl. Naz., ms. Gal. 259, fol. 13^ 

" ' Saggi di naturali esperienze jatte neWAccademia del Cimento 

(Florence, 1667), plate 1. 

"» Le Roy, Mem. Acad. r. Sci. Paris (1751), pp. 481-518. 

i"Daniell, Quart. J. Sci., vol. 8 (1820), pp. 298-336. 

64 
FIGURE 59 

MHT 319,467. Reproduction of the condensation hygrometer invented by Archduke Ferdinand II of Tuscany, On a brass tripod is supported a hollow conical frustum of cork, coated with 

pitch inside and covered on the outside with sheet 

metal. The cone is continued into a pointed 

glass vessel, off" the end of which condensed 

moisture could drip into a graduated glass. 

There is also a drain for the water resulting from 

the melting of the ice put in the cone. Overall 

height, 64 cm. Received in 1961. (Smithsonian 

photo 61902-G.) 

FIGURE 60 

MHT 318,271. Daniell-type dew-point hygrometer with a gilt band around the lower bulb, 

to facilitate observation of the dew. The bulbs 

are about 4,5 cm in diameter, the glass parts 20 

cm wide by 21 cm high overall. The internal 

thermometer has its white-glass scale enclosed, 

and is graduated from —20 to +50° G; the external thermometer, with an open white-glass 

scale, from —10 to +50° G. It is marked "Celsius" and is attached to a turned wooden stand 

26 cm high, "Germany" is stamped on the bottom of the turned base. Presented by Cornell University in 1960. (Smithsonian photo 61899-B.) 

65 
contain nothing but ether and its vapor. To 

use it, the instrument is tilted so that most of the 

ether is in the uncovered bulb; the bulb that is 

covered with muslin is then moistened with 

ether from a bottie. The evaporation of this 

causes the ether in the instrument to distill over, 

reducing the temperature of the bulb until dew 

begins to form on its surface. At this moment, the 

internal thermometer is read. In the Museum's 

specimen MH T 318,271, there is a gilt band 

around the bulb, a later improvement. 

There are two possible sources of serious 

error with this instrument. One is the gradient 

of temperature between the surface of the bulb 

and the thermometer; however, this error can be 

greatiy reduced by noting the temperature at 

which the dew disappears, as well as that at 

which it forms. The other is less tractable and 

results from the frequent presence of small 

amounts of water in the ether used to cool the 

bulb. To get away from this, it is better to evaporate the ether in the chamber that is to be cooled 

by drawing air through it and discharging the 

resulting vapor at a distance. The best design for 

a hygrometer operated in this way is probably 

that of Alluard,"^ represented in the Museum 

by specimen MH T 323,821 (figure 61), in 

which a comparison surface, not cooled, surrounds the surface on which the dew is formed. 

FIGURE 61 

MHT 323,821. AUuard's modification of Regnault's dew-point hygrometer. Ether in a 

square brass tube has air drawn through it 

to cool the tube so that dew will form. A thermometer in the tube can be observed through 

glass windows. There are small tubes, with 

taps, for connection to an air supply and an 

exhaust. The metal tube is 1.9 cm square x 

10 cm high. The overall height of the instrument is 26 cm, and the circular metal base is 

11.5 cm in diameter. On the comparison plate 

surrounding the front surface of the tube is 

engraved "Wm, Gaertner & Go. Chicago," 

Presented in 1964 by Kalamazoo College, 

Kalamazoo, Michigan. (Smithsonian photo 

61907-A.) 

Psychrometers 

The empirical knowledge that a damp surface 

is cooled by evaporation must be very ancient, 

but it only begins to be noted in connection with 

the thermometer about the year 1740,"® It is 

likely that one of the first to use a moistened 

bulb to measure the dryness of the atmosphere 

was the geologist James Hutton (1726-1797)."° 

What was needed was a theory; and this was 

"8 Alluard, Journal de Physique, vol. 7 (1878), pp. 328-30. 

"» Gf. G. F. Gigna, Miscellanea Taurinensia, vol. 2 (1760), 

p. 144. 

"0 According to his biographer John Playfair, Trans. R. 

Sac. Edinburgh, vol. 5, part 3 (1805), p, 67, note. 

66 
FIGUR E 62 

M HT 230,007. Psychrometer made for the 

Signal Service. Two mercury thermometers are 

mounted on a beveled-edged pine board 

25 x 15 X 2 cm. Brass straps bring the thermometers 2.5 cm in front of the board, and 

the left-hand support has an additional piece 

holding a nickel-plated waterpot. The thermometers, mercury-in-glass, with cylindrical 

bulbs, are mounted on flat brass strips 24 x 

2.3 x 0.15 cm. Their scales are etched on the 

tubes, which have white-glass strips drawn in 

them, and the numbers and main graduations 

are on adjacent strips of white glass. Thermometer number 1868 also has the tube numbered, and is graduated from —40 to +11 8 

[°F]. Thermometer number 3070 is graduated 

from —20 to +11 6 [°F]. Besides the numbers, 

each thermometer is marked "Signal Service 

U.S. Army," and number 3070 is marked 

" H . J. Green N.Y." Transferred from the 

Weather Bureau in 1904. (Smithsonian photo 

61833-E.) 

FIGURE 63 

M H T 314,552. Sling psychrometer. 

Two thermometers, so arranged that 

the wet-bulb projects farther than the 

dry bulb, are attached to the aluminum alloy frame. The frame is joined 

by two wire links and a swivel to a 

handle of polished maple. The bulbs of 

the mercury-in-glass thermometers are 

cylindrical, 1.5 cm long and 0.4 and 

0.5 cm in diameter respectively. Each 

thermometer is 23 cm long and is 

graduated from —40 to +130 ° F. 

The frame is engraved "H.J. Green 

B'klyn. N.Y. N° 648 U.S. Weather 

Bureau." The thermometers are etched 

"U.S. 8078" and "U.S. 8079" respectively, and the numbers "8078" and 

"8079" also appear on the frame. This 

instrument, which is said to have been 

used by Richard E. Byrd, USN, during 

his flight to the North Pole, 9 May 

1926, was transferred from the Weather 

Bureau in 1954. (Smithsonian photo 

62145.) 

67 
FIGURE 64 

MHT 317,725. Well-made psychrometer of Russian origin, bearing the 

numbers A735203 and N124936, and 

very similar to the original Assmann 

psychrometer except that it has an 

electric motor, 110 volts A.C, or 

D.C, to operate the centrifugal 

suction fan. The thermometers are 

very delicate enclosed-scale thermometers (see page 41) graduated in 

fifths of a degree. Total length, 43 

cm; diameter of fan casing, 8,9 cm. 

It is in a wooden box, containing a 

certificate dated 1942. Transferred 

from the Weather Bureau in 1960, 

(Smithsonian photo 61829-C,) 

FIGURE 65 

METT 314,864. Two thermometers forming a 

psychrometer, with a computing device, were 

patented by J. Winlock and J.S.F. Huddleston 

(U.S. Patent 149,176, 31 March 1874). A 

wooden case 32 x 13 x 16 cm forms a support 

for the thermometers and contains the computer. This has a brass scale marked in units of 

two from 4 . to 100, representing dry-bulb 

temperature, next to a narrow window 0.7 cm 

wide through which, by turning a knob at the 

top of the instrument, any one of 22 scales 

headed 1 to 22 (degrees of the depression of the 

wet bulb) can be made to appear. The relative 

humidity is read from the appropriate scale 

opposite the dry-bulb temperature. The wetbulb thermometer is marked "Huddleston, 

Boston"; the dry-bulb thermometer "Hygrophant Patented March 31, 1874 805." A water 

container is missing. Transferred from the 

Smithsonian Astrophysical Observatory in 1956. 

(Smithsonian photo 61830-A.) 

68 
first provided by James Ivory in 1822,"^ and 

refined three years later by Ernst August "^ who 

gave to the combination of a dry-bulb and a wetbulb thermometer the rather unfortunate name 

psychrometer or "cold-meter" which it has 

borne ever since, August is generally but unfairly considered the inventor of the instrument. 

The psychrometer, then, consists of two thermometers, one of which is covered with a film of 

water, held by some thin wettable material such 

as cambric. The variations on this simple theme 

mainly involve means of assuring a suitable and 

constant motion of air past the bulbs of the 

thermometers. The simplest type of psychrometer, 

used at countiess meteorological stations, is 

represented in the Museum by specimen MH T 

230,007, figure 62, This has no provision for 

artificial ventilation. One way of ensuring this 

is to whirl both thermometers around for some 

time, then stop them and read them at once. An 

apparatus for this purpose, such as MH T 

314,552, is known as a sling psychrometer 

(figure 63). 

A much better though more complicated way 

of ventilating a psychrometer was devised about 

1890 by Richard Assmann,^^ In his "aspiration 

1" Ivory, Phil. Mag., vol. 60 (1822), pp. 81-88. 

«* August, Annalen der Physik, vol. 5 (1825), pp. 69-88; 

335^4. 

^^ Assmana, ^eits. jiir lustrum., vol. 12 (1892), pp. 1-12. 

Also Abh. des K. preuss meteorol. Insts. vol. 1 (1892), pp. 115-

270. 

psychrometer" a clockwork fan draws air past 

the bulbs of the thermometers, which are enclosed in double-walled ducts of polished metal 

in order to minimize the efTect of radiation. The 

Museum has a Russian instrument of this sort, 

but with an electric, rather than a clockwork, 

motor (MHT 317,725, figure 64). 

To derive the dew point, vapor density, or 

relative humidity from the readings of the two 

thermometers involves a calculation, or at best 

a double-entry table. During the 19th century a 

number of devices were invented and patented, 

incorporating a slide-rule, nomogram or other 

computing device into a stand or holder for the 

two thermometers. An example is MH T 314,864 

shown in figure 65. A much more sophisticated 

instrument, not quite complete, is MH T 325,390, 

which makes use of a nomogram. 

MHT 325,390. Psychrometer with nomogram, 

consisting of two thermometers (one missing) 

on a frame 17 x 25 cm, with a nomogram and 

directions for its use on a piece of card attached 

between the thermometers. A knob and lever 

system permits two pointers to be set on auxiliary scales to the dry-bulb and wet-bulb 

temperatures. When this has been done, a third 

pointer indicates on the nomogram the relative 

humidity, the dew point, the vapor pressure, 

and the weight of vapor in grains per cubic 

foot of air. This instrument was patented on 

9 April 1878, by N. M. Lowe of Boston, Massachusetts (U.S. Patent 202,276), Presented in 

1964 by the Drexel Institute of Technology, 

Philadelphia, Pennsylvania. 

69 
Instruments not Referred to in the Text 

Hair Hygrometer 

315,744. Hair hygrometer with pulley. Hair and 

counterweight missing. Scale 0 (on right) to 100, 

marked "Secheresse" and "Humidites [sic].^^ Also 

inscribed "Fortin & Hermann Gen^®. [?] a Paris." 

Brass frame on cast brass base. Overall height, 35 cm. 

This instrument, purchased in 1829 by the U.S 

Military Academy, was transferred to the Museum 

in 1958, 

Condensation Hygrometers 

315.733. A hygrometer of Daniell's type, similar to 

MHT 318,271 described on page 65, except that it 

had a black-glass bulb, now broken, as is also the 

internal thermometer, the ivory scale of which is 

graduated from 13 to 95 [°F]. The external thermometer has been lost. Overall height 16 cm, width 10 

cm. Transferred from the U.S. Military Academy 

in 1958. 

315.734. Daniell-type hygrometer, similar to MHT 

318,271 except that it has Fahrenheit thermometers, 

the internal one having an enclosed rolled-paper 

scale. The bulbs are 4 cm in diameter, the overall 

height 25 cm, the width 18 cm. Transferred from the 

U.S. Military Academy in 1958. 

Psychrometers 

308,200. Two sling psychrometers, similar to MHT 

314,552 except that the bulbs of the thermometers 

measure 1.5 cm x 0.3 cm. The frames are marked 

"H. J. Green B'klyn. N.Y.N? 117 [and "N° 147" 

respectively] Signal Corps, U.S. Army." Transferred 

from the Signal Corps in 1923. 

309,319. Psychrometer with Winlock and Huddleston's computing device, similar to MHT 314,864 

except for the wooden stand, which is a conical frustum. Overall height, 37 cm. Transferred from the 

U.S. Patent Office in 1926. 

314,561. Psychrometer, The frame and mounts similar 

to 230,007, but the waterpot is missing. The dryand wet-bulb thermometers are on metal plates 

24 X 2.3 X 0.15 cm, with formed grooves, scales on 

the tubes, and the numbers repeated on the mounts. 

Dry-bulb: -3 5 to +139 [°F], marked "H. J. Green 

B'klyn. N.Y. No. 5097 U.S. Weather Bureau." Wetbulb: -2 7 to +117 [°F], marked "H. J. Green 

B'klyn. N.Y. No. 4860 U.S. Weather Bureau." The 

brass mount for the dry-bulb thermometer is stamped 

"J. P. Friez, Bait, Md." Transferred from the Weather 

Bureau in 1954. 

316,419. Two thermometers and a brass stand, in a 

fitted mahogany case, 35 x 12x5 cm. Each thermometer is marked "Jas. Green, 175 Grand St. New York." 

One thermometer is graduated from —15 to +130 

[°F] in half degrees and is 26 cm long. The other, 

fitted to the stand, is graduated from —10 to +120° 

and is 20 cm long. The case contains a stoppered 

bottle and an eyedropper. Transferred from the U.S. 

Military Academy in 1959. 

317,477. Two mercury-in-glass thermometers, mounted on each side of the hinged split lid of a wooden 

box, 27 X 5.3 X 2.5 cm. One thermometer, number 

4137, has its cylindrical bulb covered with muslin; 

the other, number 4135, is broken. Both are on flat 

nickel-plated mounts, the tubes bearing the divisions 

and the mounts the numbers. The box contains a 

small brass tube closed at one end, to hold water 

for wetting the bulb. Transferred from the Weather 

Bureau in 1960. 

317,726. A ventilated psychrometer. This military 

instrument, of German make, has lost its thermometers. It has a motor-driven fan at the bottom, drawing 

air past the bulbs from the side through an elbow. 

(This sacrifices one of the advantages of the Assmann 

psychrometer referred to on page 69.) It stands 

46 cm high and is packed in a heavy wooden case 

containing a 220 V to 12 V transformer and connecting cords and plugs. Transferred from the 

Weather Bureau in 1960, 

70 
317,727. A small Assmann psychrometer, with a 

spring-driven fan. Overall length 22 cm, diameter 5.0 

cm. The enclosed-scale thermometers are only 14 cm 

long, graduated from —28 to +42 [°C], and bear 

the numbers 12207 and 12208. The instrument is 

marked "R. Fuess Berlin-Steglitz 1121460." It is in 

a fitted box 8 cm x 8 cm x 24 cm, containing the usual 

accessories and a spare thermometer, number 12867. 

Transferred from the Weather Bureau in 1960. 

321,863. A psychrometer for use in coal mines, with 

a leather case. Two thermometers bearing the Kew 

Observatory test numbers 32075 and 32076 are 

mounted in a brass tube 6.3 cm in diameter and 23 cm 

long, cut out on two sides, and marked "John Davis 

& Son (Derby) Ltd. No. 443 Derby & London. 

Reg. No. 518758." Presented in 1962 by Mr. C. F. 

Brooks, Superior-Sterling Company, Bluefield, West 

Virginia. 

71 
FIGURE 66 

MHT 230,008. Standard Weather Bureau "8-

inch" rain gauge, made of galvanized iron, with 

the rim of the funnel of brass, and sharp edged, 

defining a collecting area 8 inches (20.3 cm) in 

diameter. The vertical sides of the funnel are 5.6 

cm high inside. The funnel discharges into a 

brass tube 6.3 cm in diameter and 51 cm long, 

closed at the bottom. This tube has slightly more 

than one-tenth the cross-sectional area of the 

funnel, and to measure the depth of water in the 

tube a thin wooden scale is used (cross section 

1.4 cm X 0.2 cm), graduated in tenths of an inch 

and numbered in hundredths. There are two of 

these with the specimen, which also includes a 

strong iron stand, made of two castings and three 

rods, designed to hold the mouth of the gauge 

about 30 inches (76 cm) above the surface to 

which the stand is fastened. Transferred from 

the Weather Bureau in 1904. (Smithsonian 

photo 61832.) 

FIGURE 67 

MHT 315,898. Reproduction of the rain gauge 

recommended by the Smithsonian Institution to 

its observers in the mid-19th century. It has a 

copper funnel 13.2 cm surmounting a glass jar. 

Overall height, 36 cm. See Tenth Annual Report of 

the Board of Regents of the Smithsonian Institution for 

1855 (Washington, 1856), p. 229. (Smithsonian 

photo 61903-D.) 

72 
Chapter 5 

Instruments for the Measurement 

Of Precipitation and Evaporation 

The early history of the rain gauge was dealt 

with by Gustav Hellmann,"* who came to the 

conclusion that it was invented independentiy in 

India (4th or 5th century B.C), Palestine 

(A.D. 1st or 2nd century) and Korea (A.D. 15th 

century). In any event the rain gauge is the 

oldest meteorological instrument giving quantitative results. In the West it was not until 1639 

that an isolated experiment on the measurement 

of rain was recorded in Italy. 

From the beginning, a rain gauge has been 

simply a vessel with an open top, exposed to the 

sky. After a rain, the depth of water in the vessel 

was measured. In the 17th century, it was found 

that the reading of the gauge could be made 

easier and more accurate by leading the rainwater from a relatively large surface into a vessel 

of much smaller area, and measuring the depth 

in that. This involved the determination of the 

dimensions of the apparatus. All the hundreds 

of rain gauges designed in the last three hundred 

years—apart from recording gauges—have been 

variations in the same simple apparatus. Such 

instruments are represented in the collections by 

two specimens, MH T 230,008 (figure 66) and 

M H T 315,898 (figure 67). 

The first attempt at a recording gauge seems 

to have been made by Sir Christopher Wren, 

who on 22 January 1661-62, described to the 

Royal Society ^^ a vessel which emptied itself 

when a certain amount of water had flowed into 

it—a "tipping bucket." ^^^ Rain gauges using 

this principle are common in North America, 

but today a double-tipping bucket is preferred, 

which overbalances itself in such a way that the 

stream of water from the collecting funnel begins 

to flow into the other half of the bucket. When 

this is full, the bucket tips again. Each reversal 

of the bucket operates a counter or recorder, 

either mechanically, as in MH T 314,529, or 

electrically. 

MHT 314,529. Mechanical parts, incomplete, 

of a tipping-bucket raingauge designed for 

public display in a "Kiosk" (see page 47), It 

*'* Hellmann, Beitrdge zur Erfindungsgeschicte meteorologischer 

Instrumente (Berlin, 1920), pp. 39-48. 

*^ Royal Society, Journal Book. 

'2' The principle of the tipping bucket itself is, however, 

much older. 

73 
FIGURE 68 

MHT 314,713. Mechanism of a tipping-bucket rain gauge. The frame is made of 

two square brass bars 28 cm long screwed to fiber endpieces. Contacts are made 

between leaf springs each time the bucket tips. Overall length, 30 cm. Transferred 

from the Weather Bureau in 1955. (Smithsonian photo 61902.) 

FIGURE 69 

Tipping bucket mounted in the 12-inch rain 

gauge. (Figure 5 on page 9 of U.S. Weather 

Bureau Circular E, Instrument Division, 4th ed., 

1922; Smithsonian photo 63884.) 

consists of a double tipping bucket and a rocking 

shaft that, through a ratchet, operates a counter 

with two pointers, indicating amounts of rainfall from 0 to 12 inches in 0.01-inch steps. Whiteenameled dial marked "Julien Friez Belfort 

Baltimore, MD. U.S.A. Inches Rainfall." After 

operating the buckets, the water falls into a copper tank 20 X 6 X 14 cm and runs out through a 

spout. Transferred from the Weather Bureau in 

1954. 

In the latter case, each tip of the bucket momentarily closes a switch, as in the mechanism 

represented by MH T 314,713 (figure 68), 

which fits into a gauge with a collecting 

funnel 12 inches in diameter, as shown in 

figure 69.^^^ The electrical impulses are recorded 

by a chronograph, usually the "triple register," ^^' 

placed indoors. 

Another way of recording rain, and also snow, 

is to weigh the precipitation caught by a pipe 

of known area. Marvin's "weighing rain and 

snow gauge" ^^® is essentially an unequal-arm 

balance with the vessel for the precipitation on 

"7 U.S. Weather Bureau, Measurement oj precipitation. 

Gircular E, Instrument Division, 4th ed. (Washington, 

1922), p. 9. 

128 See p. 123. 

^29 U.S. Weather Bureau, Instructions jor using Marvin's 

weighing rain and snow gauge (Washington, 1893). 

74 
FIGURE 70 FIGURE 71 

MHT 314,538. Electromagnetic device for 

recording the indications of a Marvin weighing 

rain gauge. A brass drum 9.7 cm in diameter 

and 11 cm long is rotated by an internal clock. 

A pen arm is carried on a sleeve that slides 

along a rod in which are cut both right-hand 

and left-hand square threads. The sleeve, which 

is prevented ft-om rotating, carries a specially 

designed pin which rides in the thread and 

reverses the motion of the sleeve at each end 

of its travel. The threaded rod is rotated through 

a small angle by a ratchet and pawl every 

time a pulse of current from the rain gauge 

passes through an electromagnet. The cast-iron 

base, 32 x 28 cm, carries a brass plate marked 

"U,S, Weather Bureau Rain Gauge register 

No. 10 Made by Julien P, Friez Baltimore, 

Md," There is a glazed cover 27 x 22 x 18 cm. 

Transferred from the Weather Bureau in 1954. 

(Smithsonian photo 61905-A.) 

MHT 308,203. Fergusson recording precipitation gauge, final form. Rain or snow falling 

through an aperture 8 inches in diameter is 

collected in a cylindrical bucket supported 

on a specially designed spring balance. The 

pen linkage is extremely ingenious; by the design 

of the links and the relative weights of the 

various parts, the pen is caused to cross the 

chart three times while the receiver is moving 

downwards to its full extent, A dashpot containing glycerine prevents oscillations due to 

wind, A detachable furmel, removed when 

snow is expected, further reduces the effect, 

and also tends to prevent evaporation. The 

clock drives the drum one revolution per day. 

Overall height, 64 cm. Transferred from the 

Signal Corps in 1923. (Smithsonian photo 

61907-C.) 

the shorter arm, and a weight moved along the 

longer arm by an electrically operated ratchet 

and pawl whenever the balance needs to be 

restored. At the same time, a pen is moved a 

corresponding amount in the recording mechanism, MH T 314,538 (figure 70). 

A rain gauge may make its record on the site, 

with no need for electricity. The weighing precipitation gauge of S, P. Fergusson, first designed 

when he was at Blue Hill Observatory,"" is of 

this type. The specimen in the Museum, MH T 

"0 Fergusson, American Meteorological Journal, vol. 

(1888-89), p. 321. 

308,203 (figure 71), is of an improved type."^ 

By mounting the tipping bucket on a balance, 

it is possible to make a rain gauge that gives a 

continuous record on a very open scale. In the 

century before 1960 a large number of such 

designs appeared, of which the Museum has a 

very elegant one, MH T 316,814, made by 

Richard Freres of Paris, "^ It is shown in figure 

72, 

131 Fergusson, Monthly Weather Review, vol. 49 (1921), 

pp. 379-84, 

"2 Richard Freres, Notice sur les instruments enregistreurs . . . 

(Paris, 1889), pp. 24-26. 

75 

29,9-340 0-^9 -
FIGURE 72 

MHT 316,814. Recording rain-gauge mechanism 

built by Jules Richard of Paris about 1890. The 

tipping buckets, 20 cm long and 9 cm wide, are 

mounted on a Roman balance which gradually 

descends under the increasing weight of water 

collected by one of the buckets, and through a 

system of levers causes a pen to rise in proportion to the added weight of water. When 10 mm 

of rain have accumulated, the buckets tip, and 

the pen returns to zero. The tipping is slowed 

down by a fan governor geared up from a shaft 

moved by the buckets. The instrument is on a 

mahogany base 43 x 45 cm, and has a glazed 

metal cover 37 x 36 x 36 cm with a hole in the 

top for the pipe coming from the collecting funnel. The baseplate is marked "Richard Freres 

Constructeurs Brevetes Paris 10298 Made in 

France." This was at Mount Weather, Virginia, 

and was transferred from the Weather Bureau 

in 1959. (Smitiisonian photo 61909-B.) 

A large number of recording rain gauges using 

floats, some with collecting chambers emptied by 

siphons, have been designed and are used to some 

extent in many countries. They are easily 

damaged by frost, however, and scarcely used at 

all in North America. The type is not represented 

in the Museum, 

Apart from measuring the amount of rainfall, 

there is—or was—some interest in recording the 

beginning and ending of light rain. A way of 

doing this was first devised about 1860 in 

France,"^ and an instrument in the Museum 

(MHT 316,817) is a much later form designed 

by S. P. Fergusson and used in the 1920s at a 

133 Herve-Mangon, Annuaire Soc. Meteorol. de Frarue, vol. 8 

(1860), pp. 183-84. 

76 
few stations of the Weather Bureau,"* The idea 

is to expose a moving record sheet, crosshatched 

in-a somewhat soluble ink, to the sky through a 

small hole, so that the crosshatching will be 

blurred where it becomes wet. There are also 

time lines on the moving paper. This instrument 

has received the name of "ombroscope." 

MHT 316,817. "Ombroscope." A drum 20 cm 

in diameter and 15 cm long is driven by internal 

clockwork and turns on a shaft having a fast 

screw thread working in a fixed nut, so as to advance the drum axially as it turns, A hole in a 

rounded cover is close to the top of the drum. 

The device is on a cast-iron base 52 cm long 

and 28 cm wide. There is no indication of its 

origin. Transferred from the Weather Bureau in 

1959. 

The supply of water for precipitation is replenished by evaporation from land and sea, and 

at least since the time of Claude Perrault (1613-

1688) attempts have been made to measure the 

amount of water evaporated, ^^* The early experimenters simply measured or weighed the water in 

a vessel before and after it had been exposed to 

the air, but it was soon realized that vessels of 

different sizes and shapes would give widely 

different results. It was also realized that much 

evaporation takes place from the leaves of plants 

and from the soil, so that there is some point to 

exposing damp surfaces of porous earthenware,^^* 

paper, ^^^ or even earth, ^^^ The one instrument of 

this sort in the Museum is a recording evaporation gauge, or atmograph, from Japan, MH T 

316,273, shown in figure 73. 

"* Roy N. Covert, Journal oj the Optical Society oj America & 

Review oj Scientific Instruments, vol. 10 (1925), pp. 345-46. 

"« Perrault, Hist. Acad. Sci. 1666-86 (Paris, 1733), vol. 1, 

pp. 115-16; Edmond Halley, Phil. Trans., vol. 18 (1694), 

pp. 183-90. 

" ' John Leslie, A short account oj experiments and instruments 

depending on the relations oj air to heat and moisture (Edinburgh, 

1813), p. 81. 

"^ Albert Piche, Bull. Assoc. Sci. de France, vol. 10 (1872), 

pp. 166-67, 

"3 A. Bellani, cited by Muncke in Gehler's Physikalische 

Worterbuch (Leipzig, 1825-45), vol. 1, p. 436. 

FIGURE 73 

MHT 316,273. Japanese atmograph, recording 

the evaporation from an area of absorbent paper 

(3.5 cm in diameter) in contact with a mass of 

cotton wick dipping into water in a vertical 

tube (2.2 cm in diameter). This tube is connected by a side tube to a cylinder 5.3 cm in diameter containing a float linked to a pen arm. 

The vertical tube has a filling plug and a drain 

cock. The cast-iron base and sheet-metzJ 

cover are of the design and dimensions common 

in the United States (see figure 58, MHT 

327,634), The clock and drum are also very 

similar. This instrument, which dates from 1944, 

is marked "H, Ota No. 529." Transferred from 

the Weather Bureau in 1959. (Smithsonian 

photo 61906-A.) 

Instrument not Referred to 

In the Text 

MHT 316,818. Part of an experimental recording rain 

gauge, incomplete, but probably had tipping buckets. 

It is in a copper box 23 x 18 x 25 cm, on four legs 

13 cm high, and with a copper lid. Transferred from 

the Weather Bureau in 1959. 

77 
FIGURE 74 

MHT 247,698. Circular plate of wood, 32 cm in 

diameter and 2.2 cm thick, with 32 hoppershaped depress'ons near the edge, each with a 

hole at the bottom. A written label is fixed to 

the upper surface of the plate, and reads as 

follows: "The Base of a self-registering Wind 

Vane erected by James H. Coffin in 1837 at 

Ogdensburg, N.Y. A hopper attached to the 

foot of the vane rod received a continuous stream 

of dry sand. A spout six inches long carried from 

this hopper, one ounce of sand every fifteen 

minutes, and dropped it into the appropriate 

receptacle. At the end of the month the sand 

contained in these thirty-two receptacles, was 

weighed. The number of ounces thus showed the 

duration of the wind for each of the points of the 

compass. A plate in the Appendix of Coffin's 

'The Winds of the Globe' [published in the 

Smithsonian Contributions to Knowledge, volume 20; 

Washington, 1876] gives the results obtained by 

this, and other apparatus made by him at 

Ogdensburg." Presented in 1907 by Professor 

Selden J. Coffin. (Smithsonian photo 61904-B.) 

78 
Chapter 6 

Instruments for Measuring 

The Surface Wind 

Wind Vanes and 

Wind-direction Recorders 

The wind vane is the best known of all meteorological instruments, and also one of the oldest, 

for there seems to have been a wind vane on the 

"Tower of the Winds" built at Athens by 

Andronicus of Cyrrha about 50 B.C.*'' A few 

years afterwards, Marcus Terentius Varro (ca. 

114-26 B.C.) had a wind vane on his farm, the 

position of which was indicated by a pointer 

inside his house."" Sixteen hundred years later 

Egnatio Danti, the bishop of Velletri, used 

gearing to make a wind vane show the direction 

of the wind by means of a verticzd dial and 

pointer mounted on a wall."* Meanwhile, innumerable "weathercocks" had been mounted 

139 Vitruvius, On Architecture, trans. Frank Granger (Loeb 

Classical Library, Cambridge, Massachusetts, and London, 

1955), p. 57 (book 1, chapter 6, paragraph 4). 

140 Varro, De re rustica, book 3, chapter 5, paragraph 17. 

See the translation by T. Owen (Oxford, 1800), p. 214. 

"1 Danti, "La fabbrica dello anemoscopio, strumento 

verticale" in his Prima volume dell'uso etjabbrica dell'astrolabio, 

et delplanisjerio . . . (Florence, 1578), pp. 273-281. 

on the steeples of churches and the towers of 

public buildings. The first mechanical improvement of any importance was described by Johann 

Georg Leutmann in 1725,"^ He provided a 

conical pivot bearing to carry the weight of the 

vane. 

For centuries, wind vanes had been flat plates, 

until in 1797 G. F. Parrot described the so-called 

"splayed" vane, which had two plates making an 

acute dihedral angle, and giving a greater turning moment for small changes in the direction of 

the wind."' In the 20th century many forms of 

wind vane have been introduced,"* the best of 

them making use of airfoil sections. 

The Museum of History and Technology has 

comparatively few scientific wind vanes, though 

some of the anemometers to be described in the 

next section have vanes incorporated in their construction in order to make them face the wind. 

"2 Leutmann, Instrumenta meteorognosiae inservientia (Wittenberg, 1725), p. 116. 

"* Parrot, Magaz. jilr den neuesten Z^tand der Naturk., 

vol. 1 (1797), pp. 154-58. 

"* See E. Kleinschmidt, ed., Handbuch der meteorologischen 

Instrumente (Beriin, 1935), pp. 338-40. 

79 
FIGURE 75 

Diagram of the Smithsonian Institution's wind vane of 1860. MHT 

322,611 is a model (60 cm long and 37 cm high) of this. 

FIGURE 76 

MHT 315,906. Flat vane, strongly constructed of heavy metal, with a gilt arrow. 

The base of the vane carries four insulated sectors, one or two of which can be touched 

by a contact arm rotating with the vane. Overall length 91 cm, height 65 cm. Transferred from the Weather Bureau in 1958. (Smithsonian photo 61903-B.) 

80 
The oldest and most interesting specimen is a 

smgJl part of a wind-direction recorder designed 

in 1837 by the pioneer American meteorologist 

James H. CoflSn (1806-1873) of Ogdensburg, 

New York (MHT 247,698, figure 74), The 

depressions carved in this plate can be nothing 

more than funnels, leading sand from a rotating 

spout to an array of boxes or jars beneath the 

board. 

In 1860 a recording wind vane was in operation at the Smithsonian Institution in Washington, "^ and there is a model of the vane, MH T 

322,611, in the Museum. It is on a scale of about 

one tenth. The original was enormous, the 

"feather part" being "composed of two pieces of 

pine board about one foot wide, eleven feet long, 

and half an inch thick." As shown in figure 75, 

the shaft rotated a box containing a clock-driven 

mechanism that drew a pencil radially inwards 

while the changes in wind direction were moving 

it in circular arcs. 

The remaining three specimens are more 

recent in design and have to do with electrical 

recording. By providing a vane with a contact 

on its shaft and giving the contact suitable dimensions, it can be made to touch one of four 

insulated segments of a conducting ring when the 

vane is pointing within 22K degrees of one of the 

cardinal directions N, E, S, and W, and to touch 

two of them when it is within 22)^ degrees of the 

intermediate directions NE, SE, SW, and NW. 

Thus, with five connecting wires and a suitable 

recorder, the wind direction may be recorded to 

eight directions. MH T 315,906 (figure 76) is 

such a vane. With eight segments and nine wires, 

16 directions can be distinguished and recorded 

by an eight-pen recorder such as MH T 308,193 

(figure 77). 

For use in airport control towers it is valuable 

to have a distant indication of the wind direction 

that is not limited to eight or sixteen points. This 

can be done very easily by the use of the so-called 

self-synchronous motors, small electric motors 

FIGURE 77 

"8 Annual Report oj the Board oj Regents of the Smithsonian 

Institution ior 1860 (Washington, 1861), pp. 414-16. 

MHT 308,193. Electrical wind-direction recorder capable of recording to 16 directions by 

means of 8 pens operated by 8 electromagnets. 

Each magnet makes a jog in a line, drawn by 

its associated pen, when a contact arm revolved by a suitable wind vane is touching the 

sector that pertains to it. In a wooden case 25 

X 14 X about 18 cm (the glazed top is missing), the array of electromagnets is mounted on 

a brass plate 21 x 8.8 cm, as is a drum 9.2 cm 

in diameter x 11.4 cm high. The drum contains 

an integral clock of the usual Richard type, 

which revolves it in seven days. On the brass 

plate is the Richard Freres trademark and the 

number 82862. Transferred ft-om the Signal 

Corps in 1923. (Smithsoniarf photo 61906.) 

with rotors fed with single-phase alternating 

current, and three-phase stators connected together. When either of two such motors is rotated by external means, the shsift of the other 

will rotate to exactly the same extent, provided 

it is not overloaded. The Museum has the indicating part of a Japanese installation of this kind 

(MHT 316,269), 

MHT 316,269. A self-synchronous indicator in 

a heavy cast-iron case, 19 cm in diameter and 

10 cm deep, marked "Nishin Electrical Inst, 

Works. Model 98," It has a translucent illuminated dial with a rheostat for adjusting the 

brightness. Transferred ft-om the Weather 

Bureau in 1959. 

81 
FIGURE 78 

MHT 318,489. Reproduction of Hooke's 

swinging-plate anemometer. It is of brass and 

copper except for the plate, which is of wood. 

The scale is marked "10, 20, . . . 80." Overall 

height 50 cm, base 15 cm in diameter, quadrant 

17 cm in radius. Made by L. C. Eichner in 

1961. (Smithsonian photo 61902-B,) 

FIGURE 79 

MHT 325,389, Demonstration model of a 

pressure-tube anemometer and wind vane, 

after Lind. The glass tube is 2.4 cm in diameter 

and 24 cm high, the brass vane 25 cm long. 

There is an iron base 12,5 cm in diameter, 

carrying a wind rose in red on a silvered brass 

plate. Marked "llDll, " Presented in 1964 by 

the Drexel Institute of Technology, Philadelphia, Pennsylvania. (Smithsonian photo 

61830-B.) 

Anemometers and Anemographs 

Instruments for measuring the speed of the 

wind fall naturally into four main classes, all 

represented in the collection. These classes are: 

• Pressure-plate anemometers. 

• Pressure-tube anemometers. 

• Rotation anemometers. 

• Anemometers depending on cooling. 

Of these the oldest is the pressure-plate anemometer, the idea of which might naturally occur to 

anyone who had seen a shopkeeper's sign swinging in the wind, but Leon Battista Alberti (1404-

1472) seems to have been the first to record the 

suggestion,"® in a sketch of a rectangular swinging plate supported at one edge, and a quadrant 

to indicate its inclination to the vertical. The 

same idea occurred—sdmost certainly independentiy—to Robert Hooke, "^ and his swingingplate anemometer is represented in the Museum 

by a reproduction, MH T 318,489, figure 78. 

The wind blowing into the open end of a tube 

increases the pressure within it, while if it blows 

i« Alberti, Opuscoli morali (Venice, 1568), p. 253. This 

was written about 1452. 

i« Anon., Phil. Trans., vol. 2 (1667), p. 444. 

82 
across the end it reduces the pressure. The first 

anemometer depending on this principle was 

suggested in or before 1722 by Pierre Daniel 

Huet,"^ It was reinvented by James Lind half a 

century later,"« and the Museum has a model 

(MHT 325,389, figure 79) constructed approximately according to his illustration, but provided with a wind vane to face the tube into 

the wind. Since the excess and deficit of pressure 

vary as the square of the wind speed, the scale 

of such an instrument is far from linear. 

In more recent times, the perfection of the tube 

anemometer has been associated with the name 

of William Henry Dines (1855-1927), who first 

became attracted to anemometry when investigating the force of the wind on engineering 

structures. In order to make it unnecessary to 

point the suction tube exactiy at right angles to 

the wind stream, he used the device of drilling a 

large number of radial holes in a smooth tube, 

as in the portable anemometer (MHT 314,951) 

shown in figure 80."° 

With the cooperation of the London instrument maker R. W. Munro, Dines also designed 

a recording anemometer in which the pressure 

in a tube facing the wind acts on the underside 

of a float and the suction in a vertical tube 

with four rows of holes is applied above it. The 

Museum has one of these instruments, MH T 

316,813, and it is more informative to reproduce 

a cross section of such an instrument "^ in 

figure 81 than a photograph of the outside of the 

specimen in the Museum. The reader's attention 

is directed to the trumpet-shaped inner surface 

of the float, which makes the deflection of the 

pen linear in wind speed. The correct theory 

of this float was first given by E, Gold,"^ 

" ' Huetiana; ou pensees diverses de M. Huet, Evesque 

d'Avranches (Paris, 1722), pp. 55-58. 

"9 Lind, Phil. Trans., vol. 65 (1775), pp. 353-65. 

"0 A patent application seems to have been made and 

abandoned. 

•" Dines, Collected Scientific Papers (London, 1931), p. (11). 

"* Quarterly Journal Royal Meteorological Society, vol. 62 

(1936), pp. 170-77, 

FIGURE 80 

MHT 314,951. Portable anemometer 

of W. H. Dines. It operates on the 

suction produced when the wind blows 

past a tube with a number of small 

drilled holes. A glass tube 26 cm long 

is cemented into a small cistern at 

the bottom and into a brass tube 2.6 

cm in diameter and 4.7 cm long that 

has 12 co-planar holes drilled in it, 

each about 1.2 mm in diameter. There 

is also a brass screw ending in a pad, 

which can be used to seal the end of 

the glass tube for transport. On each 

side of the glass tube is a scale, engraved on brass, on the left 0 to 30 lbs 

per square foot, and on the right a 

square-law scale up to 100 miles per 

hour. The cistern, the upper tube, and 

the scale are machined out of a single 

brass bar 30.6 cm long. A bayonet 

fitting allows the anemometer to be 

supported in a brass tube 31.4 cm 

long and 3.1 cm in diameter, which 

forms a handle when the inner part 

is pulled out, and a container when 

it is pushed in. There is a brass-wire 

bail for hanging the instrument up. 

Overall length: closed, 35 cm; open 

60 cm. Engraved on the inner part, 

"Dines Patent Portable Anemometer 

84" and on the outer tube, "L, Casella. London." Deposited by the 

Smithsonian Astrophysical Observatory 

in 1956. (Smithsonian photo 61829-B.) 

We now come to the rotation anemometers, 

which are of two main classes: windmill (or 

propeller) anemometers and cup anemometers. 

It was natural that the windmill, an old device, 

should be used to measure the speed or force 

of the wind, and this was first done in the 18th 

century,"^ though Christian von WolfPs windmill was prevented from rotating continuously, 

the deflection from a zero being a measure of 

153 Christian von Wolff, Aerometriae elementa (Leipzig, 

1709), pp. 320-23. 

83 
WATE

R LEVEL— 

FIGURE 81 

Diagram of the recording part of the Dines— 

Munro pressure-tube anemometer, MHT 316,-

813 consists of the head as well as the recording 

part. The head is a flat vane measuring 15 x 26 

cm, arranged to direct a tube 2.5 cm diameter 

and 20 cm long into the wind. This tube 

communicates with the bottom of the recorder 

through a long pipe. The vane is supported 

by a rod and a long sleeve bearing, nearly 

airtight, above a larger tube 5.4 cm in diameter 

and 22 cm long, which is perforated with four 

rows of holes, 20 in each row. This tube com-

municates with the top of the recorder. The 

recorder is in the form of a tank 26 cm in di-

ameter and 74 cm high, on a base with 3 leveling 

screws, and provided with a water-level gauge. 

It has a cast-brass plate marked "Dines's 

Pressure Tube Anemometer. R, W, Munro 

Maker London," The top of the tank is closed 

by a plate 37 cm in diameter, through which 

the fitting for the pen arm (missing) protrudes, 

and which carries a recording drum 12.7 cm 

in diameter and 22 cm long, with an internal 

clock. This drum is marked "Negretti & 

Zambra, London" and is probably not original. 

Overall, the instrument stands 106 cm high. 

Transferred from the Weather Bureau in 1959. 

(Diagram from figure 1, page 11, in Collected 

Scientific Papers of William Henry Dines.) 

FIGURE 82 

MHT 316,275, Japanese windmill-type anemom-

eter and wind vane for transmitting indications 

electrically to a distance. On a pipe mast 60 cm 

long is supported a splayed wind vane 35 cm 

long and 18 cm wide, built on to a rectangular 

metal box 18 x 7 x 4,5 cm containing a cam-

operated contact system geared to a 6-bladed 

mill 29 cm in diameter, with flat elliptical 

blades. The rotation of the vane moves three 

insulated contacts around three composition 

resistors, forming the transmitting portion of an 

electromagnetic wind-direction indicator. These 

parts and their corresponding terminals are 

protected by a galvanized iron tube 7 cm in 

diameter and 25 cm long. Transferred from the 

Weather Bureau in 1959, (Smithsonian photo 

61833.) 

84 
the wind force. For meteorological use, a windmill or propeller is necessarily combined with 

a wind vane so that the former faces into the 

wind at all times. The Museum has one example, 

M H T 316,275, figure 82. A more common form 

of this general type is intended to be held in 

the hand, for measuring the movement of air 

in ducts, mine workings, and tunnels. For this 

purpose a light mill is usually mounted in a 

short tube that almost fits it, as in MH T 308,183, 

figure 83, which has the unusual addition of a 

stopwatch interconnected with the counter that 

registers the revolutions of the windmill. 

For meteorological observations the cup anemometer, invented by T, R, Robinson in 1846 ^s* 

after he had thought about some experiments 

by R. L. Edgeworth, i^s has the advantage that 

no wind vane is needed to direct it. Furthermore, it can be made very strong. For many 

years the standard anemometer of the U.S. 

Weather Bureau was the type represented by 

i« B.A.A.S., Southampton, 1846, Sections, pp. 111-12. 

155 Edgeworth, Phil Trans., vol. 73 (1783), pp. 136-43. 

FIGURE 83 

MHT 308,183. Windmill anemometer having 

8 vanes in a tube 9.3 cm in diameter and 5.3 

cm long, mounted on a rectangular tube carrying a stopwatch and a measuring dial in 

"metres," engraved "Jules Richard Constructeur Paris." The stopwatch and the gearing are 

so interconnected that when the watch is 

started the counter is automatically connected 

to the windmill. Transferred from the Signal 

Corps in 1923. (Smitiisonian photo 61833-A.) 

85 
FIGURE 84 

MHT 230,001. Cup anemometer by JuHen P. 

Friez. It has 4 aluminum hemispherical cups 

each 10 cm in diameter on a radius of 17 cm to 

their centers. The wheel is supported by a journal 

bearing at the top and a pivot at the bottom of 

the tubular frame, which enlarges at the bottom 

to a cylinder containing a counter in "miles" 

and "tenths" and electrical contacts that close a 

circuit once for every mile of wind, each tenth 

contact being of longer duration. Overall height, 

41 cm. This type was first used by the Weather 

Bureau in 1871. Transferred from the Weather 

Bureau in 1904. (Smithsonian photo 61829.) 

FIGURE 85 

Diagram of a chronograph ("single register"). 

MHT 308,204 has a drum 9.7 cm in diameter 

and 9.2 cm long which is turned and simultaneously moved axially by means of a clock and 

a fast screw. A pen makes a helical line on the 

paper that covers the drum except when an 

electrical impulse from an instrument (anemometer) jogs it briefly sideways. The instrument 

is on a heavy japanned iron base, 39 x 33 cm, 

and is marked "Julien P. Friez & Sons Belfort 

Observatory Baltimore Md." Transferred from 

the Signal Corps in 1923. (Diagram from U.S, 

Weather Bureau Circular D, 2d ed., 1900, 

figure 16 on page 41; Smithsonian photo 63888.) 

86 
FIGURE 86 

MHT 252,975. Cup anemometer with 4 cups 7.6 cm in 

diameter on a radius of 15 cm to their centers, supported 

15 cm above a brass box 12 x 3 x 4.5 cm high, which 

contains 4 geared counter wheels indicated as "1000 M," 

"100 M," "10 M," "1 Mile." Marked "J. W. Queen & C . 

Philadelphia." Transferred from the U.S. Geological 

Survey in 1909. (Smithsonian photo 61829-A.) 

the specimen 60,203M, in which the cups are 

geared to two counting wheels. 

60,203 M (Division of Military History). 

Cup anemometer, having four hemispherical 

brass cups each 6.3 cm in diameter on a radius 

of 10 cm to their centers. The wheel is supported 

by a journal bearing at the top and a pivot at 

the bottom of the tubular frame, which enlarges at the bottom to a cylinder containing a 

counter in "miles" and "tenths." Overall height 

21.5 cm. All is of brass construction except for 

iron radial arms. Marked "A, Hahl & Co,, 

Bait., Md." This type was first used by the 

Weather Bureau in 1871, when it was part of 

the Army Signal Corps, from which this instrument was received. 

This standard type of anemometer is also 

represented by MH T 230,001, figure 84, in 

which one of the wheels carries pins that operate 

an electrical switch, enabling distant recordings 

of the run of the wind,^^^ by the use of a chronograph or "single register" (MHT 308,204), 

which is illustrated by the use of an engraving, 

figure 85.^^^ Both these instruments were introduced in the 1870s. 

Cup anemometers made without electrical 

recording are exemplified by the rather smaller 

instrument MH T 252,975, shown in figure 86, 

1^' See U.S. Weather Bureau, Instructions jor . . . wind 

measuring and recording apparatus, Circular D, Instrument 

Division. 2d ed., 1900, pp. 9-23. 

"' Ibid., p. 41, 

87 
IBMMfflMlBti. "I'OAJUJUW aejiafcj" 

FIGURE 87 

MHT 316,001. Kata-thermometer, with a cylindrical bulb 3.5 cm 

long and 1.8 cm in diameter, and a tube 0.6 cm in diameter, containing red spirit. The tube has only two graduations, and there is 

a white-glass back strip. On the front of the tube is etched "Mean 

36.5° C," and on the back "N°. 2562 J. Hicks 8, 9, & 10 Hatton 

Garden London F472." Overall length, 22.5 cm. Deposited by the 

Smithsonian Astrophysical Observatory in 1958. (Smithsonian photo 

61836-E.) 

The relative merits of 3-cup and 4-cup wheels 

were the subject of acrimonious discussion, 

which seems to have led to a fairly general 

adoption of the 3-cup anemometer. The Museum has such an anemometer and its associated 

recorder (MHT 316,943). 

MHT 316,943. Anemometer and recorder. The 

cup wheel consists of 3 cups 12.7 cm diameter 

with centers 15.8 cm from the axis. The wheel is 

supported 28 cm above a counter and contact 

mechanism (similar to MHT 230,001) marked 

"Henry J. Green Scientific Instruments B'klyn. 

N.Y. U.S.A." The recorder has a drum driven 

by a clock, 1 revolution in 6 hours, and traversed 

axially by a coarse screw. An electromagnet jogs 

a pen at each contact made by the cup wheel. 

Similar to MHT 308,204 (figure 85) except for 

the glazed wooden case, which measures 35 x 

25 x 8 cm, and bears a brass plate engraved 

"Hahl & Co Balto M^" Presented in 1960 by 

the Lick Observatory, University of California. 

One of the advantages of rotation anemometers 

is that it is possible to incorporate a small permanent-magnet A.C. generator, the current from 

which can be rectified and measured on a milliammeter. The Museum possesses the indicating 

portion of such a combination, MH T 316,270, 

MHT 316,270. Electrical indicator for use with 

rotation anemometer. A cast-iron case, 18 x 20 x 

13 cm, marked "Nishin Denki, Kyoto, 1942. 

Model 98," contains a milliammeter with a dial 

reading from 0 to 60, and a rheostat to control 

the transillumination of the dial. Transferred 

from the Weather Bureau in 1959. 

The various anemometers, used chiefly for 

special research, which measure the speed of the 

wind by its cooling power, are represented in 

the Museum only by the Kata-thermometer,^^^ 

devised primarily for biometeorology. This is an 

alcohol-in-glass thermometer with a relatively 

large bulb, having two marks on the scale at 

35° G and 38° G, a range which brackets the 

normal human body temperature. To use it, the 

thermometer is warmed to slightiy above the 

upper mark, and hung in the wind. The time 

taken for the temperature to fall from 38 to 35° G 

is measured with a stopwatch, and related to the 

wind speed by a previous calibration. Like all 

anemometers of this sort, it is particularly suitable 

for measuring very low wind speeds. One of the 

specimens in the Museum, MH T 316,001, is 

shown in figure 87. 

158 L. Hill, O. W. Griffith, and M. Flack, Phil. Trans., 

Section B, vol. 207 (1915), pp. 183-220. 

88 
Instruments not Referred to in the Text 

308.181. Four-cup anemometer, similar to MHT 

230,001 apart from unimportant details, except that 

the cup wheel is braced by four strips of metal between 

the arms. Marked "Anemometer No. 1031. Type 

1—1/60 Mile Julien P. Friez and Sons Baltimore, 

Md., U.S.A." Transferred from the Signal Corps in 

1923. 

308.182. Windmill anemometer, marked "A. Stoppani & C° S. A. Berne," consisting of eight aluminum 

vanes mounted in a tube 9 cm in diameter, and 

geared to two dials, reading 0-100 meters and 0-100 

hectometers. With the dials is mounted a stopwatch. 

Transferred from the Signal Corps in 1923. 

314,535. A cup anemometer with four hemispherical 

cups 10 cm in diameter, their centers at a radius of 

17 cm firom the vertical shaft. The rotation of the cups 

operates counting wheels that can total up to 1,000 

miles of wind, and a contact system that makes a contact for each mile of wind, with a longer contact at 

every tenth mile. Overall height, 41 cm. Marked 

"USWB 1580-S." Transferred from the Weather 

Bureau in 1954. 

316,268. A Japanese version of the Dines—Munro 

tube-anemometer head, similar to that in MHT 

316,813, but marked "Suzuki Meteorological Inst, 

Co., Tokyo 1944 Serial 6104." Overall length 50 cm, 

height 50 cm. Transferred from the Weather Bureau 

in 1959, 

317,274. A windmill anemometer having 10 vanes 

running inside a brass tube 15.3 cm in diameter and 

4.6 cm long. A dial is geared to the mill and graduated 

in feet from 0-100; a small dial is marked "Hds," 

0-10. Signed "Keuff'el & Esser Co. New York." The 

mahogany case, 18x18x 7 cm, has a correction table 

inside the lid, headed "Anemometer No. N5967-

11673." Presented in 1960 by the Department of 

Chemistry, Yale University. 

317,457. A Kata-thermometer, similar in general 

appearance to MHT 316,001, but 21 cm long and 

graduated from 35 to 40 [° C]. It is marked "J. Hicks 

8 9 & 10 Hatton Garden London N° 261 F531." 

It was purchased by the Weather Bureau in 1919, 

and transferred to the Museum in 1960, 

323,501. An electromagnetic counter for use with a 

cup anemometer, in a wooden case 15 x 11 x 7.5 cm. 

It is unsigned, but there is a penciled notation 

"Counter, Revolution From Mt Weather Nov 7, 

1934." Transferred from the Weather Bureau in 1963. 

89 
c / 

FIGURE 89 

FIGURE 88 

Construction of the electrical sunshine recorder. (Figure 1 on page 

2 of U.S. Weather Bureau Circular G, 5th ed., 1941; Smithsonian photo 63887.) 

MHT 308,176, Sunshine recorder of the differential-thermometer type, for electricEil recording. A glass tube, 2.2 cm in diameter and 25 

cm long, contains a differential thermonaeter 

with a black bulb and a clear bulb and a narrow 

tube between them, dipping into the blackened bulb, which contains mercury and alcohol. 

There are two platinum wires sealed into the 

connecting tube, and led to terminals on a 

metal base that permits the instrument to be 

pointed north and south at an appropriate 

angle. This catalog number covers two separate 

instruments which are marked "Sunshine Recorder, Type ML20, Signal Corps, U.S. Army, 

Serial 15 (40 in the second specimen). Order 

110429, Date 5-5-23." Transferred from the 

Signal Corps in 1923, (Smithsonian photo 

61837-F,) 

90 
Chapter 7 

Sunshine Recorders 

Instruments for recording the duration of sunshine can be divided into two distinct classes; 

those that make use of the heat of the sun, and 

those that employ its actinic effect. 

The earliest of the first class, the so-called 

Campbell-Stokes sunshine recorder, ^^® is used in 

many countries, but is not represented in the 

Museum's collection. In this instrument the sun's 

rays, collected by a sphere of optical glass, burn 

a track in a specially prepared card. It is really 

a sort of recording sundial. In the United States 

a sunshine recorder based on the differential thermometer of John Leslie,^*" and made into a 

recording instrument by D. T, Maring and C. F. 

Marvin,*®^ was adopted as standard at the stations of the Weather Bureau and the Signal 

Corps. The heat of the sun expands alcohol vapor 

in a blackened bulb, causing mercury to connect 

two platinum wires sealed into an inner tube. 

"^ J. F. Campbell, British Meteorological Society, Report oj 

Council for 1857, p. 18. G. G. Stokes, Quarterly Journal 

Meteorological Society, vol. 6 (1880), pp. 83-94. 

"» Leslie, J. Nat. Philos., Chem., & the Arts, vol. 3 (1799), 

pp. 461-67. 

"^ See Julien P. Friez, Illustrated Catalogue oj Meteorological 

Instruments and Apparatus . . . (Baltimore, 1893), pp. 39-40. 

Also D. T. Maring, Monthly Weather Review, vol. 25 (1897), 

pp. 485-90. 

The internal construction of this instrument is 

shown in figure 88, and its actu2d appearance in 

figure 89, which is a photograph of one of the two 

specimens in the Museum, MH T 308,176. This 

sunshine recorder is used in connection with the 

"triple register" or station meteorograph described in chapter 11.^®^ 

The photographic recorder is fundamentally 

a pinhole camera, the image of the moving sun 

passing across a piece of sensitive paper, usually 

blueprint paper, as the day progresses. The first 

such instrument was invented by T, B. Jordan 

about 1838.*®' Two of the photographic recorders 

in the Museum are apparentiy experimental; 

they are numbered 248,689 and 248,690, 

MHT 248,689. Photographic sunshine recorder. 

The nickel-plated tube (12.7 cm in diameter and 

12 cm long) is mounted on a base with a scale 

of latitude so that the axis of the tube may be 

directed to the celestial pole. In lines parallel 

to the axis, and 90° apart, are two series of 

seven very small holes, which can be exposed 

one at a time by moving a dovetail slide having 

a single larger aperture. Inside the tube are 

'«2 See pp. 123-24. 

"» T. B. Jordan, Royal Cornwall Polytechnic Society, Annual 

Report jor 1838 (Penzance, 1839), p. 184. 

91 

288^40 O—69-
FIGURE 90 

Diagram of a photographic sunshine recorder. 

Specimen MHT 314,5§9 has a metal tube 

(10.0 cm diameter and 18.5 cm long) mounted so 

that its axis can be directed to the celestial pole, 

a scale of latitude being provided. The tube is 

closed at its upper end, and a removable cap 

is provided at its lower end through which two 

pieces of photographic paper can be inserted 

and held by wire clips in sectors of cylinders 

back to back—one for morning, the other for 

afternoon. Along two sides of the main tube, at 

about 45° to the top, are fastened dovetail 

slides with slots 13 x 0.3 cm. On these slides 

move brass pieces, 26.5 x 38 x 0.4 cm, each with 

a small central hole and a scale reading 1 to 31. 

A serrated edge enables these slides to be set 

to correspond with the day of the month and 

held by means of a spring catch. One pair of 

record sheets thus suffices for a month's record. 

Each of the slides is marked "Julien P. Friez, 

Balto. Md. U.S. Weather Bureau N9 55." 

Transferred from the Weather Bureau in 1954, 

(Diagram from Julien P. Friez's Catalogue, 1893, 

figure 24 on page 38.) 

92 
two cylindrical sectors back to back, with terminal grooves for holding pieces of photographic paper. By moving the slides, seven 

days' record can be obtained on the two pieces 

of paper. The push-on cover of the tube is 

marked "U.S.G.S." The instrument may be 

assumed to have been constructed by the U.S. 

Geological Survey from which it was transferred in 1908. 

MHT 248,690. Experimental photographic 

sunshine recorder, consisting of a metal box, 

12.5 X 6.5 X 7 cm, with a push-on cover. Two 

edges are beveled for 3 cm and contain tiny 

central holes. Inside the box, two quartercylinders receive pieces of photographic paper. 

The whole is supported on a hinged quadrant 

with a rough latitude scale, unnumbered. The 

entire instrument is roughly constructed and 

has no markings. Transferred from the U.S, 

Geological Survey in 1908. 

The third, MH T 314,539, figure 90, was designed 

by C. F. Marvin about 1890,*"* and still used by 

the Weather Bureau at some stations twenty 

years later.'"^ When the hours of sunshine are 

counted, such instruments do not give the same 

results as the electrical sunshine recorder, and 

indeed it is very difficult to make sunshine 

recorders comparable. 

"< Op. cit. (footnote 112), pp. 38-39. 

"5 C. F. Marvin, The Care oj Sunshine Recorders . . . , U.S. 

Weather Bureau Circular G, 3d ed. (Washington, 1911), 

pp. 7-12. 

Instrument not Referred to in the Text 

MHT 314,714. A sunshine recorder of the differentialthermometer type, exactiy as MHT 308,176 except 

for markings. Transferred from the Weather Bureau 

in 1955. 

93 
FIGURE 91 

MHT 230,004. Fineman reflecting nephoscope, 

A glass plate 22 cm in diameter, blacked at the 

back, is engraved with concentric rings of 5 and 

10 cm radius, and a diametral scale 10-0-10 cm, 

in millimeters. This can rotate about a 

central axis supported on three leveling screws 

and surrounded at a distance of 6 mm. by an 

annular scale of degrees 0-360. A telescoping 

post with a cross bar can rotate independentiy 

between the plate and the scale. This instrument 

is marked "Schneider Bros. New York" and 

bears the number "U.S.W.B. No. 50." Transferred from the Weather Bureau in 1904. 

(Smithsonian photo 61836-C,) 

94 
Chapter 8 

Nephoscopes 

It was early seen that the direction of motion 

of a cloud could be determined by lining up a 

prominent feature of the cloud and some elevated 

terrestrial object, such as the top of a flagpole, 

and noting the position of the observer, who then 

moves in such a direction as to maintain the 

alignment. His direction of motion is then the 

exact opposite of that of the cloud. A refinement 

was introduced by L. Besson, who built an 

elevated "comb" that could be moved into any 

azimuth.^*® This also made it possible to determine the angular speed of the cloud by timing its 

motion between the "teeth" of the comb. 

A neater solution had been devised by C. G. 

Fineman,'®^ who provided a rotatable horizontal 

mirror provided with a suitable coordinate system, in which the cloud could be seen by reflection. There are two of these in the Museum, 

M H T 230,004 (figure 91) and MH T 316,153. 

MHT 316,153. Fineman reflecting nephoscope, 

similar to MHT 230,004 except that it bears 

the number "U.S.W.B. No. 11." It is badly 

corroded. Transferred from the Weather Bureau 

in 1959. 

"^ L. Besson, Arm. Soc. meteorol. France, vol. 45 (1897), 

p. 172. 

"" C, G. Fineman, J^jiits. jilr Instrum., vol. 6 (1886), 

pp. 206-8. 

The potentialities of the application of modern 

technology are illustrated by comparison of the 

nephoscope with the meteorological earth 

satellite, TIROS, which enabled meteorologists 

to view in their entirety large-scale cyclones 

covering areas of more than 1500 km span. A 

backup satellite for TIROS I, launched on 

1 April 1960, is included in the collections of the 

National Air and Space Museum. 

NASM 1965-289. TIROS meteorological satellite, the name being an acronym for Television 

and InfraRed Observation Satellite. One of the 

first five built in 1959, the spacecraft is a 133 kg, 

18-sided polygon, 107 cm in diameter and 56 

cm high. Its sides and top are covered with 

9,000 solar cells which, when exposed to the 

sun's rays, recharge the spacecraft's 63 Ni-Cd 

batteries. Protruding from the top of the satellite is a 46 cm receiving antenna which receives commands from ground stations. At the 

bottom are four 56 cm whip antennas spaced at 

90° intervals, which transmit television pictures, infrared data and telemetry relating to 

spacecraft temperature, pressure, battery-charge 

levels, spin rate, etc. Two independent television 

camera systems capable of independent or 

simultaneous operation are aligned parallel to 

95 
the spacecraft's spin axis. Photographs of earth 

cloud are made on command. Each camera 

system consists of a vidicon tube and focalplane shutter. Pictures are transmitted a maximum distance of 2,500 km. Magnetic tape 

storage allows up to 64 pictures to be recorded 

and stored until readout command is given. 

Infrared detectors measure earth radiant heat 

on the night side of the earth providing data on 

land, ocean, and cloud albedo. The first TIRO S 

was launched on 1 April 1960, into a near 

circular orbit of 750 km. TIRO S I transmitted 

more than 22,500 pictures before its power 

supply failed. Transferred by the National 

Aeronautics and Space Administration to the 

Smithsonian's National Air and Space Museum. 

96 
Chapter 9 

Upper-Air Instruments, 

Not Telemetering 

Whil e the scientific study of the weathe r bega n 

in the 17th century with the invention of the 

baromete r an d thermometer, its scope w?is 

severely limited until it became possible to mak e 

measurements in the free air, beyond the reach 

of structures built on the ground. Th e invention 

of the balloon in 1783 provided the possibility of 

making sporadic observations of this sort, bu t 

anothe r century ha d to pass before the progress of 

instrumentation allowed fairly regula r observations on a planne d schedule, using kites, unmanne d balloons, an d aircraft. 

T h e close relation between aeronautics an d 

meteorology is symbolized by a numbe r of 

instruments preserved in the Smithsonian's 

Nationa l Air an d Spac e Museum. 

NASM 1963-27. Mercury barometer carried 

during his balloon ascents of 1784 and 1785 by 

Dr. John Jeffries of Boston. Soon after the news 

of the first manned balloon ascent was made 

(de Rozier and d'Arlandes in a Montgolfiere 

hot-air balloon, over Paris, 21 November 1783) 

Dr. Jeffries, then in England, arranged with the 

French aeronaut Jean Pierre Blanchard to 

make an ascent from London, on 30 November 

1784. This is believed to be the first manned 

ascent in which instruments were carried 

for determining weather conditions in mid-air 

The following 7 January Jeffries and Blanchard 

ascended from Dover and were wafted across 

the Channel, landing in the forest of Guines. 

That was the first air voyage from one nation to 

another. This instrument (with a thermometer, 

see page 39) was carried on both of these ascents 

by Dr. Jeffries. The barometer, marked "James 

& Son, London," has the dimensions 87.5 

X 11.5 cm. Presented by Dr. James Means. 

NASM 1964-673. Mercury barometer carried 

during his balloon ascents by Charles Person 

Durant (1805-1873). Durant is generally considered the first professional aeronaut in the 

United States. His first ascent was made from 

Castie Garden, New York City, in 1830. The 

instrument is marked "Globe Portable Barometer, L. Roach, maker. New York." Its dimensions are 90 x 4.5 cm. Presented by Mrs. 

Louis C. Jones. 

NASM 1931-40. Mercury barometer with thermometer, carried during his Civil War balloon 

ascents by Professor Thaddeus S. C Lowe, military aeronaut for the Federal Army, 1861-63. 

Marked "James Green, N.Y. " Overall dimensions, 96 X 2 cm. Presented by the heirs of 

T. S. C. Lowe through Mrs. Henry M. Brownback. 

97 
FIGURE 92 

M H T 308,209. Original Richard meteorograph 

for captive balloons. On a brass plate 22 x 9.3 x 

0.4 cm are mounted two strong brass posts to 

support the axes of three pen arms, operated by 

an aneroid barograph, a hair hygrograph, and a 

thermograph with a Bourdon tube in a perforated brass duct beneath the baseplate. The 

records are made in ink on a chart carried by a 

clock-driven drum 6.8 cm in diameter and 19 cm 

high. There is no fixed pen. The overall height 

of the instrument is 25 cm. The baseplate is 

marked with the Richaid Freres monogram and 

"81970." Transferred from the Signal Corps in 

1923. (Smithsonian photo 48467-H.) 

FIGURE 93 

M H T 316,156. Marvin kite meteorograph, later 

pattern with windmill anemometer, aneroid 

barometer, bronze-invar bimetal, and a bundle 

of 8 hairs. It records on a drum 9.5 cm in diameter and 14 cm long, with an internal clock. 

The aluminum case is 23 cm long, 24 cm high, 

13 cm in diameter at the smaller end and 18 cm 

at the larger. MH T 316,156 includes two identical instruments, both transferred from the 

Weather Bureau in 1959. A third meteorograph 

in the Museum (58294-N, Division of Naval 

History) was reputedly flown by Richard E. 

Byrd, U.S.N., over both the North and South 

Poles in 1926 and 1929 respectively. (Smithsonian photo 61836-A.) 

Between abou t 1890 and 1940 man y specialized 

meteorographs were designed to suit the charac -

teristics of the various vehicles, and a few of these 

ar e represented in the collection. After 1940 these 

were abandone d in favor of the radiosonde, which 

will be discussed in the next chapter. 

Meteorographs for Use 

With Kites or Captive Balloons 

T h e heyda y of meteorological kite flying an d 

captive ballooning was the period between 1900 

and 1914, though a t one or two places systematic 

observations were continued until shortiy before 

the second World War.^^^ Systematic measure -

ments of the uppe r atmospher e by mean s of 

meteorographs raised by kites wer e begu n in 

1894 a t the Blue Hill Observatory nea r Milton, 

Massachusetts. ^^^ Abbot t Lawrenc e Rotch , wh o 

188 For an account of the very elaborate installations 

developed in Germany, see Handbuch der meteorologischen 

Instrumente, E. Kleinschmidt, ed. (Berlin, 1935), pp. 474-516. 

169 Ann. Astron. Obs. Harvard College, vol. 42, part 1 (1897), 

pp. 41-42. 

98 
4^^g ^ 

FIGURE 94 

MHT 319,822. Fergusson sounding-balloon meteorograph, recording 

on a clock-driven drum covered with smoked aluminum foil. Three 

styli are moved by a Bourdon barometer, a bimetallic thermometer, 

and a hair. It is in an aluminum case with rounded ends, 21 cm long, 

8.3 cm high, 8.2 cm across at the larger end and 5.7 cm at the smaller, 

with an opening that can be closed by an aluminum slide. It bears 

a label "Friez Baltimore Reg. U.S. Patent Office." Transferred from 

the Weather Bureau in 1962. (Smithsonian photo 61837-A.) 

had founded the Blue Hill Observatory, and 

later bequeathed it to Harvard University, 

suggested to Richard Freres of Paris the construction of a special light aluminum meteorograph for kites, on the same general plan as a 

specimen in the Museum, MH T 308,209 (flgure 

92), which is of brass and was intended for use 

with captive balloons. This instrument was the 

parent of dozens of later designs for use with 

kites, captive balloons, sounding balloons, and 

aircraft. 

By 1898, the U.S. Weather Bureau had established 16 kite stations in various parts of the 

country.^''" For these, C. F. Marvin, a noted 

authority on instruments and later Chief of 

the Bureau, designed the very successful meteorograph which bears his name.^^^ Richard 

"0 Donald R. Whitnah, A History of the United States 

Weather Bureau (Urbana, Illinois: University of Illinois 

Press, 1961), p. 101. 

"1 C. F. Marvin, Instructions jor Aerial Observers, U.S. 

Weather Bureau, Circular K, Instrument Division (Washington, 1898). 

Assmann of Lindenberg, in Germany, ^" and 

W. Koppen of the Deutsche Seewarte ^^^ both 

preferred the Marvin Meteorograph to that of 

Richard, and Assmann had it copied by a German maker. He also put a fan anemometer in the 

duct, a feature later added by Marvin, and 

present in two of the instruments in the Museum 

(MHT 316,156, figure 93), which also have 

bimetallic thermometers instead of the steel 

Bourdon tubes in the first design. 

Meteorographs for Use With 

Free Balloons (Sounding Balloons)"' 

The height attainable with captive balloons or 

kites is limited to a few kilometers, and free 

1" Assmann, Arbeiten Obs. Lindenberg, vol. 7 (1912), 

p XXIII. 

"3 Koppen, Archiv. dtsch. Seewarte, vol. 24 (1901), pp. 

96-98. 

"^ The term ballon-sonde was introduced in France about 

1895. 

99 
FIGURE 95 

MHT 319,823. Jaumotte sounding-balloon 

meteorograph. A small surface of smoked glass 

is moved by the aneroid barometric element, 

while a bimetal and a hair move styli in a 

direction approximately at right angles to 

the movement of the surface. An aluminumpainted cloth cover 18.5 x 8.0 x 6.0 cm acts 

as a combined duct and radiation shield. The 

cover is labeled "USWB 1938 79." Transferred from the Weather Bureau in 1962. 

(Smithsonian photo 48467-E.) 

balloons, carrying appropriate instruments, were 

used as early as 1892 by Gustave Hermite in 

France.^^^ At first the balloons used were made 

of paper or goldbeater's skin, but about 1900 

Assmann entirely changed the technique by the 

introduction of closed rubber balloons,^^^ which 

have the great advantage that they continue to 

ascend at a fairly constant speed until they burst. 

Naturally, it was important to reduce the weight 

of the apparatus, and many highly ingenious 

meteorographs were devised, both with and 

without clocks.^" Of the former kind, the Museum has an example, MH T 319,822, figure 94, 

of the meteorograph designed by S. P. Fergusson 

in 1919.^7« 

No matter how they are lubricated, clocks 

give trouble at very low temperatures. It was 

therefore natural to save the trouble and the 

weight of a clock by making the instrument 

plot temperature and humidity against pressure. 

A very successful meteorograph of this type, 

used for over twenty years in Great Britain, 

was devised by W. H. Dines and developed 

in the years 1906 to 1909.i^» This made very 

fine lines on a surface of polished metal, the 

record being read off with the aid of a special 

microscope. There were other related designs, 

arising in various countries. At the Museum 

the type is represented by two examples of the 

Jaumotte meteorograph. i®° The first, MH T 

319,823, without its cover of aluminum-painted 

cloth, is shown in figure 95; the other is MH T 

322,321. 

MHT 322,321. Jaumotte sounding-balloon 

meteorograph, similar to MHT 319,823. The 

cover is marked "USWB 1938." Transferred 

from the Weather Bureau in 1963. 

Meteorographs for Use On Aircraft 

Between the wars, small aircraft were used 

regularly in many places to make soundings 

up to heights of 6 or 8 km. The meteorographs 

used on these flights, usually attached by shock 

cords between the wings of the biplanes common 

at the time, were almost all strengthened versions of either the Marvin or the Richard kite 

"5 Hermite, Compt. Rend. Acad. Sci., vol. 115 (1892), 

pp. 862-64. 

1'^ Int. Aeronaut. Comm., Berlin, 1902, Verhandlungen, pp. 

81-83. 

1^' See K. Keil, Uber Meteorographen fur aerologische ^wecke 

(International Meteorological Organization, Berlin, 1938), 

for many examples of each. 

"8 Fergusson, Monthly Weather Review, vol. 48 (1920), 

pp. 317-22. 

1TM Collected Scientific Papers oj William Henry Dines (London, 

1931), p p (180) and (183)-(216). 

18" J. Jaumotte, Mem. Acad. roy. Belgique, no. 1417 (1931), 

44 pp. 

100 
FIGURE 96 

MHT 322,305. Aircraft meteorograph. This is effectively the Calwagen 

instrument, with a different arrangement of the aneroid, which has 

four chambers, apparently with internal springs. The thermometer 

is a bimetal, the hygrometer a bundle of hairs. There is a time marker 

on the pen that draws the base lien. The drum measures 7 x 17 cm; 

the case is 21 cm high, 10.5 cm wide, and 44 cm long overall. Marked 

"Gebriider Winter Jungingen Hohenz No. 4659N." Transferred from 

the Weather Bureau in 1963. (Smithsonian photo 61836-D.) 

meteorograph, ^^^ usually with some arrangement for reducing the speed of the air past the 

thermometer and hygrometer. A typical example 

is that of Calwagen.^^^ The Museum has four 

aircraft meteorographs, three of them of the 

type derived from the Richard instrument. 

Figure 96 shows one of these, MH T 322,305. 

Two of these instruments, not illustrated, are: 

MHT 322,306. Aircraft meteorograph. Almost 

identical with MHT 322,305, but made by 

Bosch & Bosch. Damaged. Has a detachable 

conical frustum to put at the end of the duct 

for reducing the flow of air. Marked "Bosch & 

Bosch Prazisions-Mechanik Freiburg i. Br. 

4024N." Transferred from the Weather Bureau 

in 1963. 

"* See Keil, Uber Meteorographen jiir aerologische ^wecke, 

for details. 

1*2 E. G. Calwagen, Geojysiske Publikationer, vol. 3 (1926), 

no. 10, p. 5. 

MHT 322,307. Aircraft meteorograph marked 

"Jtilien P. Friez & Sons Inc. Belfort Meteorological Observatory, 1230 E. Baltimore Street, 

Baltimore, Md." and "Aero 1931 U.S.W.B. 

No. 82." This is the Friez version of the Richard 

kite meteorograph, made stronger for aircraft 

use, and with an aneroid bellows instead of a 

Bourdon tube. The hygrometer is a "harp" of 

hairs, the thermometer a bimetal. There is a 

-base-line pen with provision for making time 

marks by means of an electromagnet. A clock 

beneath the base drives a drum 6.8 cm in diameter and 19 cm high. The brass case is 22 cm 

long, 9.8 cm wide, and 25 cm high, and is 

rounded at its leading edge. There is provision 

for suspending it by eight shock cords. Transferred from the Weather Biireau in 1963. 

The fourth is an incomplete instrument with 

some features of design that are hard to account 

for after the lapse of three decades. 

MHT 322,309. Aircraft meteorograph marked 

"Friez Baltimore" and "U.S.W.B. 1935 N" 

36." Incomplete. Evidendy recorded on a roll 

of paper, but only the take-up roll exists. The 

101 
pressure, temperature, and humidity pens have 

collinear axes. Transferred from the Weather 

Bureau in 1963. 

Miscellaneous Apparatus 

Used in Connection 

With Upper-air Observations 

M HT 308,202. Metal scale for use in plotting 

the tracks of balloons, 77 cm long, with two 

projecting bosses, each having a hole centered 

on one edge of the scale. Graduations 0-150 

(fifths of an inch) on one edge, 0-100 on the 

other. Divisions in tenths of an inch. Not identified. Transferred from the Signal Corps in 1923. 

M H T 316,152. Valve for the purpose of letting 

the gas out of a balloon when a certain altitude 

is reached. It operates on the principle of the 

aneroid barometer, with a brass bellows. Overall 

length 23 cm. Marked "Weather Bureau Ellendale N. D. " Transferred from the Weather 

Bureau in 1959. 

MHT 316,154. Aluminum balloon valve actuated by the expansion of the balloon. The valve 

is 2.5 cm in diameter and 5.7 cm long. Transferred from the Weather Bureau in 1959. 

M HT 316,272. Japanese set of weights for filling balloons to a given free lift. These are for 

large balloons with necks that can be tied 

around grooved disks with diameters 9.8 or 12.0 

cm. These disks may be screwed to fittings with 

hose connections and stopcocks, ballasted by 

hollow metal cylinders of marked weights into 

which loose cylindrical weights may be inserted. They are in a fitted wooden case 38 x 

23 X 10 cm. Transferred from the Weather 

Bureau in 1959. 

M HT 316,811. Plated metal sphere 30 cm in 

diameter, with a smaller concentric sphere inside. Stated to be for the storage of helium. 

There are two taps, a boss with a screwed cap, 

and three other openings, one connected by a 

tube to the internal sphere. A ring stand of 

iron, 30 cm in diameter, is provided. Transferred from the Weather Bureau in 1959. 

102 
Chapter 10 

Radiosondes 

The instruments described in chapter 9 were 

able to furnish a great deal of information about 

the upper air, but only after much delay and, in 

the case of sounding balloons, on the assumption 

that they would be found and returned. The 

possibility of obtaining such information at once 

only appeared with the refinement of the techniques of radio communication, especially with 

relatively short waves. This, to a large extent 

the work of amateur operators who were being 

prevented from using the longer waves because 

of the growth of broadcasting, began in the 

early 1920s. In a radiosonde, a change of atmospheric condition causes a change in the transmitted radio signal. This is accomplished in four 

different ways: 

• Employing a time cycle; 

• Sending a coded signal; 

• Varying the radio frequency; 

• Varying the audio frequency. 

All four types of radiosondes are represented in 

the Museum's collections. 

The immediate ancestors of the radiosonde, 

nevertheless, were instruments developed in 

France and in Germany during the war of 

1914-1918 for transmitting information down a 

kite wire. In 1917, Friedrich Herath and Max 

Robitzsch replaced the recording drum of a kite 

meteorograph with an insulating cylinder revolving once every six minutes; two metal strips 

were inserted into this as in figure 97, one 

parallel to the axis of the drum, the other 

forming a helix. ^^^ When the styli of the meteorological instruments made contact with these 

strips, the primary of a small spark coil was 

energized, the secondary of which was connected 

across a spark gap in the kite wire in parallel 

with a capacitor. At the ground, a telephone 

receiver between the kite wire and the earth 

was used to listen to the signals. In France at 

about the same time, Pierre Idrac used tuned 

circuits for both transmitter and receiver in this 

sort of carrier telegraphy, noting that several 

radio frequencies could easily be used simidtaneously.^^* 

In the Herath and Robitzsch instrument, the 

reading of each meteorological element had 

a one-to-one relation with the time between two 

signals, assuming a uniform rotation of the drum. 

This principle, which has been used in a number 

of radiosondes, really dates back to 1874, when 

E. H. von Baumhauer of Haarlem designed a 

i8» Manuscript, cited by P. Duckert, Beitr. Phys. jreien 

Atm., vol. 18 (1932), pp. 73-4-. This ms. seems to have been 

lost (according to a private communication from Dr. Karl 

Keil). Note that the axial wire could have been replaced 

by a fixed contact. 

1" E. Roth6, Compt. Rend. Acad. Sci., Paris, vol. 170 

(1920), p p 1197-98. 

103 
FIGURE 97 

Diagram of the telemeteorograph of Herath 

and Robitzsch. 

FIGURE 98 

MHT 319,827. Radiosonde of the Robert 

Bureau type, built about 1932. It is marked 

"Constructeurs Mecaniques et Electriques P. 

de Presale 104-106, Rue Oberkampf, Paris 

(XI®) Type PTU," and has the serial number 

3567. It is in an aluminum-painted box 27 x 16 

X 13 cm; the vacuum tube and the batteries are 

missing. Transferred from the Weather Bureau 

in 1962. (Smithsonian photo 61837-D.) 

telemeteorograph of this sort for use on land.^^^ 

A different apparatus on the same principle was 

built by the Dutch instrument maker H. Olland^^^ 

after reading Baumhauer's paper, and from that 

time onward such instruments have been said 

to operate on the "Olland system." It is more 

just to refer to them as time-cycle instruments. 

It should be made clear that the helix can be, 

and at various times has been, replaced by a flat 

plate with a radial conducting line, or by a 

conducting equiangular spiral. The essential feature is the variation of the time between contacts 

as the meteorological elements vary. 

Experiments with radio communication from 

a free balloon to the ground seem to have begun 

in Germany and the U.S.S.R. in the early 

1920s,^^'' but the first open publication known 

to the writer came from France, where on 

7 March 1927, a 4-watt transmitter was heard 

from high in the stratosphere.^^* Idrac and 

185 Baumhauer, Archives Neerlandaises, vol. 9 (1874), 

pp. 230-58. 

186 For more information on Olland, see M. Snellen, 

Arch. Neerl, vol. 14 (1879), pp. 180-208. 

187 Moltchanoff, Gerlands Beitr. Geophys., vol. 34 (1931), 

pp. 36-56; Hergesell, in Beitr. Phys. jreien Atm., vol. 18 

(1932), p. 50. 

188 P. Idrac and R. Bureau, Compt. Rend. Acad. Sci., vol. 184 

(1927), pp. 691-92. 

104 
FIGURE 99 

MHT 316,262. Mechanical parts of a Moltchanoff radiosonde, apparently the later type, 

but if so, incomplete. In this instrument, a series 

of six star-shaped cams with various numbers of 

points is operated by a windmill through gearing. 

The choice of the cam which makes contact at 

a given moment is made by a second switch operated by the appropriate meteorological instrument—a Bourdon-tube barometer, a bimetal thermometer, and a bundle of hairs. The 

windmill also operates a flat insulating disk with 

3 -f- 10 switch points and a switch arm. This 

forms part of the humidity circuit and has other 

functions. The instrument, made of aluminum, 

measures 21 cm long x 6 cm wide x 23 cm high, 

exclusive of the windmill. It bears the number 

39097. Transferred from the Weather Bureau in 

1959. (Smithsonian photo 48467-A.) 

Robert Bureau immediately began the development of a radiosonde, making their first ascent 

on 17 January 1929,^** with a time-cycle device 

transmitting indications of temperature and 

pressure. In May 1930, Robert Bureau, who introduced the term radiosonde, wrote a paper ^*° 

in which he explored fully and logically the 

various possible ways of modulating or altering 

a radio signal so as to transmit meteorological 

information. The Museum has an example, 

(figure 98) of one of the later French radiosondes developed under Bureau's direction in 

the 1930s (MHT 319,827). The distinguishing 

"'Bureau, Compt. Rend. Acad. Sci., vol. 188 (1929), pp. 

1565-66. 

"o La Meteorologie, vol. 7 (1931), pp. 304-17. 

feature of this time-cycle radiosonde is in the 

means adopted to make it unnecessary for the 

clock to keep an exactiy uniform rate of rotation. 

A toothed wheel is geared to the rotating cylinder of the time-cycle mechanism; this wheel 

forms one plate of a small capacitor in the LC 

circuit of the transmitter, and produces a frequency modulation of the signal, giving records 

with a number of "pips" that is a function of 

the pressure or temperature, followed by a blank 

space. 

The next radiosonde to be publicly described 

was that of Pazel A. Moltchanoff."^ In this both 

191 Moltchanoff, Gerlands Beitr. Geophys., vol. 34 (1931), 

pp. 36-56. 

105 
FIGURE 100 

Diagram of Moltchanoff's circuit, 1936. (Figure 27 on page 45 in the International 

Meteorological Organization, Aerological Commission, Uber Radiosonde-Konstruktionen. Denkschrift, Berlin, 1937; Smithsonian photo 63880.) 

temperature and pressure are transmitted in 

steps by two arms, each making contact with an 

assembly of metal strips looking somewhat like 

a comb, which has led to the term Kammgerdt for 

such instruments. The mechanical part of a later 

Moltchanoff radiosonde "^ is in the Museum 

(MHT 316,262) and is pictured in figure 99. 

Moltchanoff's elaborate circuit of about 1936 

is shown in figure 100,"^ ^^^ ^j^^ reader must be 

"2 See L. Weickmann, ed., Uber Radiosonde-Konstruktionen. 

Denkschrift (International Meteorological Organization, 

Beriin, 1937), pp. 45-54. 

193 Ibid., p. 45. 

106 

referred to the published account for a fuller 

description. It should be noted, however, that a 

platinum resistance thermometer with a Wheatstone bridge is switched in, and the hygrometer 

switched out, at about —20° C, and that there 

is a device to indicate the emergence of the 

radiosonde from the top of a cloud deck. 

Meanwhile, Paul Duckert at Lindenberg in 

Germany was working on a radiosonde of still 

another type, one in which the capacitance of 

an oil-filled condenser, and thus the radio frequency put out by the transmitter, was controlled 

by the temperature—^actually by a bimetal that 

moved one of the condenser plates—while 
pressure was indicated intermittently by means 

of interruptions of the signal, effected by contacts 

moved by a Bourdon-tube barometer."* Later, 

the Telefunken firm improved this radiosonde 

by sealing the entire radio circuit, except for 

the temperature-sensitive condenser, in an evacuated bulb. In this model (represented in the 

Museum collections by MH T 313,527, figure 

101), the pressure switch did not interrupt the 

"* P. Duckert and B. Thieme, Beitr. Phys. jreien Atm., 

vol. 18 (1932), pp. 50-67. 

FIGURE 101 

MHT 313,527. Duckert radiosonde of the later 

form (1932) with the entire radio circuit, except 

for a variable condenser operated by a bimetal, 

enclosed in a vacuum tube 6 cm in diameter 

and 16 cm long. A gold-plated toothed wheel, 

turned by a Bourdon tube, switches between the 

variable capacitor and a fixed one at known 

values of pressure. Overall dimensions at 16 cm 

X 8.5 cm X 31 cm high. Transferred from the 

Bureau of Standards in 1950. (Smithsonian 

photo 48467-C.) 

signal, but switched from the variable capacitor 

to a fixed one in order to provide a reference 

signal as a check on the stability of the transmitter.^^® Still later "^ the thermometer was 

greatiy improved by replacing the oU-filled 

variable condenser by a simple capacitor having 

a large temperature-coefficient of dielectric constant. Means were also found to transmit indications of the relative humidity in the form of 

variations in the length of time for which the 

reference frequency is turned on. 

In the first years after 1930 there were a number 

of designs of time-cycle radiosonde, some of which 

are represented in the Museum. The earliest was 

suggested by Moltchanoff and developed, rather 

elaborately and expensively, by the AskaniaWerke in Germany.^^^ Later, a much simpler instrument, invented by A. Lang and developed 

195 Duckert, Beitr. Phys. jreien Atm., vol. 20 (1933), pp. 

303-11. 

196 Op. cit. (footnote 192), pp. 25-27. 

197 Ibid., pp. 16-25. 

107 

299-340 0--69-
FIGURE 102 

Diagram of the Lang—Reichsamt fiir Wetterdienst radiosonde. (Figure 9 on page 28 in the 

International Meteorological Organization, Aerological Commission, Uber Radiosonde-Konstruktionen. Denkschrift, Berlin, 1937; Smithsonian 

photo 63882.) 

by the German Weather Service, was used for 

several years in Germany. ^^^ Its general scheme 

is shown in figure 102. A clock drives two coaxial 

insulating.cylinders, one having two conducting 

helices and the other a broad conducting band 

parallel to the axis. Instead of operating just one 

contact, the bimetal turns a star wheel, thus 

greatly expanding the temperature scale of the 

instrument. The hair moves a contact which, 

together with a fixed contact, shuts off the transmitter once a revolution for a length of time depending on the relative humidity. The aneroid 

chamber operates a switch that interrupts the 

signal at known values of pressure. The Museum 

has several specimens of which MH T 322,311 is 

the most nearly complete (figure 103). 

This radiosonde uses the time-cycle principle 

for temperature and humidity, not for pressure; 

however, in the United States and Canada several attempts were made to use the time-cycle 

principle for all the elements. An institution early 

in this field was Blue Hill Observatory of Harvard 

University, one of whose radiosondes—not the 

earliest—is represented, though not completely, 

by MH T 322,325. The instrument of which this 

formed a part is shown in figure 104. 

The radiosonde developed by the Guggenheim 

Aeronautics Laboratory of the California Institute of Technology (GALCIT) has a doubleended contact arm that touches contacts moved 

by the barometer, thermometer, and hygrometer, as well as two fixed reference contacts, twice 

each minute. ^^® The specimen in the Museum 

(MHT 319,828) lacks the tiny lead-acid storage 

batteries that operated the transmitter. 

MHT 319,828. Radiosonde, marked "Galcit 

USWB No. 430." An aluminum radiation 

shield 5.6 x 4.8 x 10 cm long contains two 

aneroid chambers, a curved bimetal, and a 

bundle of hairs. These operate contact arms that 

pass through a slot to a box containing a contact 

rotated by a special clock. The latter is in a 

transparent plastic cover. An A-frame holds a 

small radio transmitter, using an acorn tube, at 

a distance of about 10 cm from the rest of the 

instrument. The batteries are missing. Transferred from the Weather Bureau in 1962. 

The motion of any clockwork is discontinuous, and both the Blue Hill and GALCIT 

radiosondes used special clocks with more ticks 

per minute than the ordinary watch, so as to 

reduce the "least count" of the meteorological 

instruments. To produce completely uninterrupted motion, the U.S. Weather Bureau made 

experiments with a tiny air turbine, supplied 

from a small balloon filled with air, while L. F. 

Curtiss 2°" developed a small electric motor for 

the same purpose, which, with the other mechanical parts of a radiosonde, is in the Museum 

198 Ibid., pp. 28-30. 

108 

199 See O. G. Maier and L. E. Wood, J. Aeron. Sci., vol. 4 

(1937), pp. 417-22. 

200 Bulletin American Meteorological Society, vol. 18 (1937), 

p. 391. 
FIGURE 103 

• • 

MHT 322,311. Lang—Reichsamt fiir Wetterdienst radiosonde, apparentiy complete except 

for batteries, hygrometer, and radiation shield 

for the bimetal. This bimetal turns an 8-pointed 

star wheel, one of whose points makes contact 

with two conducting helices in an insulating 

cylinder. A fixed contact and one operated by a 

hygrometer connect with a conducting band 

parallel to the axis of a smaller portion of the 

cylinder. The 2-chamber aneroid traverses a 

switch arm over a raster of unequally spaced 

lines, giving contacts not far from linear in 

pressure. All this is an appendage to a white 

plastic case 16 cm in diameter and 21 cm long, 

which contains an extremely well-constructed 

and elaborate radio apparatus, with four vacuum 

tubes. The instrument is marked "W.S.E. 

2 Gerat Nr. 124 75A Anf. Zeichen Ln 28790," 

and is accompanied by calibration sheets. 

Transferred from the Weather Bureau in 1963. 

(Smithsonian photo 61836.) 

FIGURE 104 

MHT 322,325. Blue Hill radiosonde, type F, of 

1936. The small bimetal, in a radiation shield 2 

cm in diameter and 6 cm long, the hair, and the 

aneroid, move contact arms along a thin cylinder having a helical conducting wire of three 

turns let into its surface. The shaft carrying this 

helix protrudes through the top of a light wooden 

box, intended to contain a clock, a radio transmitter, and batteries. The box measures 18 x 10 

X 7 cm. There is a semicircular aluminum 

shield for the mechanical parts, and a label reading "Feiber Instrument Co. Cambridge, Mass. 

U.S.A.," with the serial number "850." Transferred from the Weather Bureau in 1963. (Figure 5 on page 117 in Bulletin American Meteorological Society, vol. 18, 1937.) 

109 
(MH T 319,830), as is anothe r experimenta l 

instrument by Curtiss an d Astin, in which a helix 

ha s replaced the contac t rotating in a plane 

(MH T 319,833). A spiral, an d a n improved 

electric motor stabilized by a weighted reed,^''^ 

was later used by Jacobsen in Canad a in a 

radiosonde tha t gave good service for two 

decades. 

M HT 319,830. Curtiss—Astin radiosonde, mechanical parts. A simple electric nnotor, in which 

a bar magnet, on a shaft with a cam-operated 

switch, gets impulses from a rectangular coil, 

drives a very light rotating contact through 

gearing. This contact touches arms moved by 

an aneroid chamber, a bimetal, and a goldbeater's skin hygrometer, as well as two fixed 

contacts. The hygrometer is broken. The assembly is 19 cm long. Transferred from the Weather 

Bureau in 1962. 

M HT 319,833. Curtiss—Astin radiosonde, experimental model. The transmitter is missing, 

but the cylindrical, corrugated cardboard box, 

15 cm in diameter and 20 cm high, with walls 

2.5 cm thick, contains an electric motor which 

drives a conducting helix through a shaft about 5 

cm long. This shaft is in a bakelite tube 1.3 cm 

in diameter, which alone supports the meteorographs. There is an aneroid chamber, a bimetal, 

and a clamp with traces of goldbeater's skin. 

All this is mounted on a cylindrical aluminum 

frame 11.5 cm in diameter and 2.7 cm high. If 

there was any shielding it has disappeared. 

Transferred from the Weather Bureau in 1962. 

T h e Julie n P. Friez Compan y of Baltimore 

also used a spiral abou t 1936, bu t it was driven 

by a clock (MH T 319,832). 

MHT 319,832. Experimental time-cycle radiosonde said by Mr. Christos Harmantas to date 

from 1936 and to have been designed by the 

Julien Friez Company. An octagonal wooden 

box, 15 cm across the flats and 14 cm high, 

contains a clock, batteries, and a radio transmitter that had two tubes (one is missing). The 

clock revolves a gold-plated spiral of only 2.0 cm 

maximum radius, and contact is made to this 

by gold wires moved by an aneroid bellows 

- av. K 2V - 50V.|f 50V. 

FIGURE 105 

Diagram of the Vaisala radiosonde, 1937. (Figure 11 on page 31 in the International Meteorological Organization, Aerological Commission, 

Uber Radiosonde-Konstruktionen. Denkschrift, Berlin, 

1937; Smithsonian photo 638 81.) 

only 1.9 cm in diameter, a straight bimetal, 

and a "harp " of hairs, as well as by two fixed 

wires. All this mechanism is mounted on an 

aluminum plate of complicated shape fastened 

to the end of the box and surrounded by two 

narrow aluminum rings, the inner one 12.6 cm 

in diameter which is held 1.5 cm away from the 

end of the box by posts. Transferred from the 

Weather Bureau in 1962. 

Time-cycle radiosondes, which once looked so 

promising, hav e been almost completely superseded by instruments of othe r types, especially 

the variable-radio-frequency an d the variable -

audio-frequency radiosondes. Th e first instrumen t in which all the meteorological elements 

are telemetered in terms of radio frequencies 

was designed in 1932 by Vilho Vaisal a of 

Helsinki.2°^ I n this, four capacitors wer e con2»i R. C. Jacobsen, Rev. Sci. Insts., vol. 10 (1939), p. 315. 

110 

202 Soc. Sci. Fenn., Comm. phys.-math., vol. 6 (1932), no. 2. 
FIGURE 106 

MHT 319,825. Vaisala radiosonde. A windmill of four conical cups puts five condensers 

successively into the transmitter circuit, three 

being controlled by the barometer, the metallic 

thermometer, and the hair hygrometer, the 

others being fixed capacitances for reference. 

Apart from the windmill, the overall dimensions 

are 22 cm high, 11 cm long, and 9 cm wide. 

Transferred from the Weather Bureau in 1962. 

(Smithsonian photo 61837-G.) 

nected successively into the LC circuit of an 

oscillator by a switch operated by a windmill. 

One was a fixed condenser to give a reference 

frequency, the others being varied by the meteorological instruments. Later, among other improvements, two fixed condensers were used,2°^ 

as in the diagram (figure 105). The instrument 

in the Museum (MHT 319,825) is shown in 

figure 106. 

A Japanese radiosonde in the possession of the 

Museum has three separate radio transmitters, 

with attachments for three antennas, for pressure, 

temperature, and humidity, respectively (MHT 

324,239). 

MHT 324,239. Radiosonde of tiie type used by 

the Japanese Navy during the years 1943 to 

1945. It has three vacuum-tube transmitters. 

Ibid., vol. 9 (1937), no. 9. 

their frequencies varied individually by an 

aneroid barometer, a hair hygrometer, and a 

liquid-in-glass thermometer filled with a 

mercury-thallium amalgam. The barometer and 

hygrometer each move one plate of a variable 

air capacitor; but the thermometer (now broken 

and nearly all missing) had a metal sheath, and 

the capacitance between this and the amalgam 

in the tube varied with the temperature. The 

high-voltage supply is by means of a vibrator 

and transformer. The whole assembly is mounted 

on a white molding and enclosed in a cylindrical 

white plastic case, 11 cm in diameter and 14 cm 

high (incomplete), with terminals for three 

antennas (missing). Transferred from the 

Weather Bureau in 1964. (We acknowledge the 

kindness of Dr. Naosuke Arizumi of the Central 

Meteorological Agency, Tokyo, in providing 

information about this radiosonde.) 

The Museum also has one of the several types 

of radiosonde devised during World War II by 

111 
FIGURE 107 

MHT 314,513. German radiosonde in which a 

pressure element and two thermometers— 

one covered with muslin—are used to vary the 

radio frequency of the signal. An electric 

motor is used to operate the switch that changes 

the connections among these and two reference 

capacitors. These last, as well as other parts of 

the transmitter, are in a light Dewar flask. 

The whole instrument except the thermometers 

is in a cylindrical aluminum case with hemispherical ends, 30 cm long overall and 8.4 cm in 

diameter. The thermometers are in an attached 

triple shield, consisting of an outer oval cylinder 

of aluminum and two concentric oval cylinders 

of white plastic. Presented in 1954 by Mr. 

Kenneth M. Perry of Falls Church, Virginia. 

(Smithsonian photo 69837-E.) 

K. Sittie and E. Manzer.^"* These are very neat 

adaptations of the variable-radio-frequency principle, with the interesting variation that temperaure and humidity are measured by a psychrometer, the two thermometers being capacitors 

with temperature-sensitive dielectrics. There is 

a specimen in the Museum (MHT 314,513, 

figure 107). 

By about 1936 it had been decided in the 

United States that a serious attempt, properly 

financed, must be made to design a radiosonde 

suitable for production in large quantities. 

FIGURE 108 

MHT 312,800. Early barometric switch for 

radiosonde. Marked "WIT" on plastic frame. 

Overall dimensions, 13 x 8.5 x 6 cm. Presented 

in 1944 by the Plaskon Co., Inc., Toledo, Ohio. 

(Smithsonian photo 61836-B.) 

This task was entrusted to the National Bureau of 

Standards, where the researches of H. Diamond, 

W. S. Hinman, Jr., and F. W. Dunmore led to a 

solution of the problem that has been the basis 

of American radiosondes to the present day.^°^ 

Their rejection of the use of any sort of clock 

or motor, eliminated the time-cycle principle 

at once. Meteorologists expressed a preference 

for a record in which temperature and humidity 

appeared as functions of pressure; and this 

preference was of course supported by the expectation that as the balloon ascended, the pressure 

would always decrease in a smooth and featureless 

curve. They therefore provided what they called 

a "pressure drive," in which an arm operated by 

an aneroid barometer makes successive contacts 

at calibrated values of pressure, as in MH T 

312,800 (figure 108). 

For the transmission of the other elements, 

they decided to modulate the radio frequency 

signal at a rate of a few hundred cycles per 

second, and design the thermometer and hygrometer so as to produce a calibrated variation in 

29^ Bulletin American Meteorological Society, vol. 31 

(1950), 341^6. 

295 Bulletin American Meteorological Society, vol. 18 

(1937), pp. 73-99. 

112 
FIGURE 109 

R 

I—AVVWW 

~u« 

First circuit of Diamond, Hinman, and Dunmore. (Figure 2 on page 75 in Bulletin American 

Meteorological Society, vol. 18, 1937; Smithsonian 

photo 63263.) 

FIGURE 110 

MHT 312,799. Hair hygrometer used with 

Weather Bureau radiosonde. A cylindrical cage 

of hairs, mounted on the upper surface of a 

light, white-plastic molding, on the lower side 

of which is a wound resistor over which a contact 

is moved by the change in length of the hairs. 

Marked "WIT." Overall length, 20 cm. 

Presented in 1944 by the Plaskon Co., Inc., 

Toledo, Ohio. (Smithsonian photo 61901-D.) 

this audio frequency. This was done by using a 

"relaxation," or RC, oscillator to modulate the 

signal, the resistance R of the circuit being varied 

by the changes in temperature or humidity. 

It should be noted that the use of a variable 

audio frequency had been mentioned as a 

possibility by Bureau in 1931.^°* 

This principle of varying the frequency of 

modulation had considerable advantages over 

that of varying the radio frequency: it used up 

less of the crowded radio-frequency spectrum; 

it was almost immune to interference; and a 

signal of constant radio frequency is almost a 

necessity for direction finding. 

Thus the thermometer and hygrometer had 

only to produce changes of electrical resistance. 

Assuming for the moment that we have ways of 

doing this, the reader is asked to refer to figure 

109, in which P is the arm operated by the 

296 R. Bureau, La Meteorol, vol. 7 (1931), p. 307. 

barometer, sweeping over a number of conducting strips in an insulating block. Certain of the 

strips, numbered 7, 6, 11, etc., in the figure, are 

wider than the rest. Connected in series between 

one of the grids of a multi-electrode tube and the 

frame of the instrument are a fixed resistor R, 

a resistor H with a contact at c operated by a 

hygrometer, and a resistance T that varies with 

temperature. 

When the pointer P is not touching any of the 

contacts, the only path from the grid to the frame 

is through all the resistors R, H, and T in series. 

In this condition the total resistance wUl be a 

function of the temperature, and so will the audio 

frequency emitted. When the pointer touches any 

of the narrower, unnumbered contacts, the total 

resistance will be R plus the portion of H between 

a and c. This is a function of the humidity. When 

it touches strips 11 and 26, the point a is connected 

directiy to the frame, resulting in an upper fixed 

frequency. When it touches numbers 1,6, 16, and 

21, the point b is connected to the frame, and a 

lower fixed frequency is produced. 

113 
FIGURE 111 

MHT 312,798. Radiosonde used by the United 

States Weather Bureau in 1942, with its foilcovered carton, 22 x 22 x 11 cm, cut away to 

permit most of the components to be seen. 

This has the electrolytic thermometer and the 

hair hygrometer that operates a variable resistor. 

It is marked "Sonde Track Manufactured in 

the United States by Washington Institute of 

Technology U.S.W.B. 1942." Presented in 1944 

by the Plaskon Company, Inc., Toledo, Ohio. 

(Smithsonian photo 61905.) 

The thermometer adopted for use with this 

circuit was, at first, electrolytic, a small V-shaped 

glass tube filled with a nonfreezing electrolyte and 

with an electrode at each end. The hygrometer 

was a bundle or a cylindrical "cage" of hairs 

operating a contact on a resistance coil, as in 

specimen MH T 312,799 (figure 110). A very 

ingenious carton was designed to hold the entire 

instrument, with flaps that could be tied back to 

expose the thermometer and hygrometer in their 

radiation shields. This sort of carton is found on 

American radiosondes until recent times, and the 

Museum has many examples, one (MHT 312,798) 

being partiy cut away to show some of the contents (figure 111). An example of the complete 

instrument (MHT 322,315) is shown in figure 

112. 

The electrolytic thermometer was later replaced 

by a semiconductor with a large temperature 

coefficient of resistance, known as a "thermistor," 

which could be made very small (MH T 327,975, 

figure 113). At a still later date, it was found that 

these thermometers could be rendered nearly 

insensitive to radiation by coating them with a 

special white paint, as in MH T 324,242. 

MHT 324,242. Two white-coated thermistors, 

each sealed in a glass tube 8 cm long. Their wire 

leads are also partly painted. Transferred from 

the Weather Bureau in 1964. 

While designing their radiosonde the workers 

at the National Bureau of Standards were 

attempting to find a satisfactory humiditysensitive resistor, a problem that has been 

attacked sporadically since about 1920.^°^ Various ideas were tried, leading finally to the 

transparent plastic strip with metallized edges 

(MHT 327,976) shown, together witii MH T 

327,975 in figure 113, as mounted for use in the 

radiosonde.^"* The adoption of the electriczd 

hygrometer made it impossible to operate with 

the simple circuit shown in figure 10.13, and a 

greatiy improved circuit was devised, necessitating the use of a relay, but having only one 

vacuum tube, a twin triode.^"* 

The Bureau of Standards radiosonde in these 

and later forms has been immensely successful. 

The fact that the telemetry depends on change 

in resistance makes it adaptable to other problems, and as early as 1939 R, Stair applied it to 

measurement of the ultraviolet radiation in the 

atmosphere.^^° The Museum has another experimental radiosonde equipped for photometry 

207 See A. Wexler, Circ. Nat. Bur. Stds., no. 586 (1957) 

for a summary of this work. 

208 This was devised in 1942 by John Onderdonk, but with 

no publication. See D. A. Mathews in Humidity and Moisture. 

Measurement and Control in Science and Industry (New York: 

Reinhold, 1965-66), vol. 1, p. 220. 

209 H. Diamond, W. S. Hinman, F. W. Dunmore, and 

E. G. Lapham, J. Res. Nat. Bur. Stds., vol. 25 (1940), pp. 

327-76. 

210 J. Res. Nat. Bur. Stds., vol. 22 (1939), pp. 295-300. 

114 
FIGURE 112 

MHT 322,315. Radiosonde in foil-covered carton, 22 X 11 X 22 cm. Two flaps open to reveal 

the electrolytic thermometer and a cylindrical 

array of hairs that operates a variable resistor. 

This apparatus is mounted on a white plastic 

molding, and enclosed in a semicylindrical 

white shield with louvers at the upper end. 

Batteries and a transmitter (heat-insulated) 

and a "baroswitch," occupy the remainder of 

the carton. Labeled "Sonde-Track Manufactured in the United States by Washington 

Institute of Technology, Washington, D.C. 

U.S.W.B. 1942 Serial No. 214024." There 

are two labels of instructions to the finder. 

Transferred from the Weather Bureau in 1963. 

(Smithsonian photo 61905-B.) 

115 
«a 

FIGURE 113 

Thermistor thermometer (MHT 327,975) and 

electric hydrometer (MHT 327,976). (Smithsonian photo 61553.) 

M H T 327,975. Thermistor, 1.0 mm in diameter 

and 4.4 cm long. Transferred from the 

Weather Bureau in 1966. 

M H T 327,976. Electrical hygrometer for radiosonde, consisting of a strip of transparent 

plastic 10.0 X 1.7 cm, metallized on the long 

edges, and coated with a hygroscopic electrolyte. Transferred from the Weather Bureau in 

1966. 

(MH T 313,528), the origin of which is not 

known. 

M HT 313,528. Special radiosonde equipped for 

upper-air photometry, in a balsa-wood box 17 x 

22 X 14 cm. This contains a pressure switch 

(similar to MH T 312,800) and also a second 

switch with six contacts, operated by an electric 

motor of the type used by Curtiss and Astin. 

There is also a 3-tube radio circuitin the box, and 

outside it are mounted two phototubes with " G 

1" etched on the glass envelope of one and "8 " 

on that of the other. Transferred from the 

National Bureau of Standards in 1950. 

FIGURE 114 

M H T 324,240. White plastic box 12 x 11.5 x 9 

cm contains a solid-state transmitter and a baroswitch and has brass arms for fastening a thermistor, supplied in a small sealed tube. There is 

provision for attaching a battery box. The instrument is marked "Radiosonde set AN/AMT 

11 B . . . Molded Insulation Co." Transferred 

from the Weather Bureau in 1964. (Smithsonian 

photo61908-C.) 

It is unnecessary to go into detail abou t th e 

various modifications of this instrument, only 

some of which are represented in the collection. 

T h e radio frequency of the signals greatiy 

increased, first to abou t 400 mc/sec an d later 

to 1680 mc/sec, because of the requirements of 

radio direction finding. Frequenc y modulatio n 

and, later, pulse modulatio n wer e introduced. 

M H T 317,728 is a n exampl e of a radiosonde 

operating on 1680 mc/sec. 

MHT 317,728. Weather Bureau radiosonde of 

1960. The parts of this radiosonde are contained 

in a white cardboard box 20 x 19 x 12 cm, out of 

which the mounting for the white thermistor 

thermometer and the electric hygrometer extend. The box is marked "Ra y Sonde Bendix 

Friez Instrument Division Bendix Aviation 

Corporation." Below the main box is a tube, 5.0 

cm in diameter and terminating in a cone and a 

smaller tube, the whole 15 cm long. This contains a transmitter operating on 1680 mc/sec. 

Transferred from the Weather Bureau in 1960. 

116 
FIGURE 115 

MHT 322,310. Radiosonde with a transponder, 

marked "Radiosonde Receiver AN/AMQ-9 

(XE-3) Serial No. 201 File No. 360-PH-55.91 

(2229) Standard Coil Products Co. Inc. U.S." 

on its white plastic case, 20 x 14 x 15 cm. From 

the top of this project fittings for a thermistor 

and an electrolytic humidity element, and from 

the bottom a white plastic tube 5.2 cm in diameter ending in a cone and a smaller tube, the 

whole 21 cm long, and containing a 1680 mc/sec 

transmitter. The marks on this are illegible. The 

main case contains a space for batteries, a clockdriven switch, and a receiver, which receives 

signals from the ground at 403 mc/sec, pulsemodulated at 75 kc/sec, and adds the audiofrequency pulses from the meteorological instruments. The output of this is used to modulate 

the 1680 mc/sec transmitter. Transferred from 

the Weather Bureau in 1963. (Smithsonian photo 

61905-C.) 

In the late 1950s, molded white plastic cases 

began to replace the corrugated-cardboard boxes 

used for two decades, and experiments were also 

made with solid-state (transistorized) radio circuits, as in MH T 324,240 (figure 114). Still more 

recentiy, the principle of the transponder has 

been adopted for some radiosondes. In this, a 

pulsed signal is sent out from the ground to the 

radiosonde, which adds information from the 

FIGURE 116 

MHT 322,313. British Meteorological Office 

radiosonde, Mark II. The transmitter and 

batteries are in a black molded-fiber box 12 

cm in diameter and 23 cm high, in the bottom 

of which is molded "Whitely Electrical Radio 

Go. Ltd. Mansfield Notts England M.O. 

[monogram] Mark II Met. Ref. N? 2807." 

The transmitting elements in rectangular aluminum shields project in three directions from the 

side of the box. In the fourth is a wheel with 

three conical cups, which revolves in the airstream to operate the switch that connects the 

three meteorological transducers in sequence. 

Transferred from the Weather Bureau in 1963. 

(Smithsonian photo 61906-B.) 

meteorological instruments and transmits back 

to the ground a modulated signal at a much 

higher frequency. The Museum has an example 

(MHT 322,310, figure 115). 

Going back to the 1930s, we find that the 

British, like the Americans, had reviewed the 

possibilities and decided independentiy on an 

audio-frequency-modulated signal,^^^ but the solution adopted at the National Physical Laboratory was quite different, especially in two respects: all the meteorological elements were 

211 H. A. Thomas, Proc. Royal Soc, Sec. A, vol. 167 (1938), 

pp. 227-50. 

117 
FIGURE 117 

MHT 322,051. Instrument package and parachute of the ARCAS 

"Rocket-Sonde." The instrument package is 10 cm in diameter and 

47 cm long. The radiosonde, type AN/DMQ-6, has a receiver, pulse 

modulator, and transmitter. A switch driven by a small motor connects four sensors, usually small thermistors, into the modulating circuit one after another. The sensors are mounted on a frame which 

is pushed out laterally when the radiosonde is freed from the nose 

cone. This catalog number also includes the rocket casing, 11.4 cm in 

diameter and 230 cm long. Presented in 1963 by the Atlantic Research 

Corporation, Alexandria,Virginia. (Smithsonian photo 61909-A.) 

FIGURE 118 

MHT 319,826. Japanese code-sending radiosonde, model "CMO-S50L." A raster of 

contacts is revolved by a small electric motor so 

as to' touch successively points moved by an 

aneroid, a bimetal, and a "harp" of about 16 

hairs. A commutator switches between these, 

and also makes contact to two tiny mercury 

thermometers, one of which disconnects the 

humidity contact at a temperature of —30° C, 

the other stops the sending of a special signal at 

— 50° C. Otherwise, the indications are interpreted by noting the sequence of the Morse 

letters N, D, B, T, M, U. The transmitter, 

which sends out a frequency of 402 mc/sec, is 

powered by a small storage battery and a vibrator. The instrument is in a white cardboard container 27 x 15 x 11 cm overall, which 

also acts as a radiation shield. Transferred 

from the Weather Bureau in 1962. (Smithsonian photo 65996.) 

118 
FIGURE 119 

M H T 324,241. German code-sending radiosonde, bearing the monogram of Dr. Graw 

Messgerate of Niirnberg and the serial number 

"5821. " A light box 10.3 cm square x 20.6 cm 

high, made of foil-coated fiberboard with sheetaluminum ends, contains a compartment, foaminsulated, for a battery (missing) and transmitter. A small permanent-magnet motor in 

the battery compartment rotates a semicylinder 

which has conducting portions of complicated 

shape. Arms operated by a barometer (2 

aneroid capsules), a thermometer (bimetal), 

and a hygrometer (a single hair) successively 

make contacts with the semicylinder. The result 

is to transmit combinations of two Morse letters 

for each meteorological element, the whole 

cycle being repeated eight times a minute. 

The hair and bimetal have separate shields 

that project on opposite sides of the instrument. 

Transferred from the Weather Bureau in 1964. 

(Smithsonian photo 61906-C.) 

measured in terms of audio frequencies, an d the 

variation of inductance , instead of resistance, 

was used to vary these. By 1940 a n improved 

design ha d been developed a t Ke w Observatory 

by E. G. Dymon d an d others,^^^ which in its 

essentials has persisted to the present time with 

some electrical modifications. 

I n this radiosonde, the meteorological instruments—a n aneroid bellows, a bimetal, an d a 

goldbeater's-skin hygrometer—^vary the air gaps 

in separate inductors with mu-meta l cores. Thes e 

inductors, as well as fixed inductors, are switched 

into the circuit one after anothe r by a switch 

operated by a cu p wheel. On e mode l of this 

radiosonde, Mar k II, is represented in the Mu -

seum by the specimen MH T 322,313 an d shown 

in figure 116. 

O n e mor e radiosonde in the Museum tha t 

works on the variable-audio-frequency principle 

must be mentioned. This is the "Rocket-Sonde, " 

sent aloft not by a balloon bu t in the nose of a 

solid-fuel rocket (MH T 322,051). Whe n the 

rocket reaches its peak altitude, the nose cone 

containing the radiosonde is released, an d also 

a parachute , which lets the instrument descend 

a t a reasonable speed. O n the way down, it 

transmits indications of temperatur e obtained by 

means of an extremely smadl thermistor; the 

direction an d range are monitored a t the same 

time, giving the height, as well as the speed an d 

direction of the uppe r winds. Th e radiosonde is 

shown in figure 117, in which the projection on 

the side is the frame containing u p to four thermistors or other sensing elements, which is pushed 

out by a spring whe n the nose cone is detached. 

Finally, there is a group of radiosondes which, 

like the Moltchanoff instrument, makes use of a 

coding device. Thes e ar e represented in the Mu -

seum by a Japanes e radiosonde (MH T 319,826, 

figure 118), which transmits signals entirely in 

Mors e code,^^^ an d a Germa n instrument, MH T 

324,241, figure 119, of a type developed abou t 

1950 and widely used for several years thereafter.21* 

212 Published only in 1947 in Proc. Phys. Soc. London, 

vol. 59, pp. 645-66. 

213 Central Meteorological Agency, Tokyo, Guide to Upper 

Air Observations, March 1951 (in Japanese). We are indebted 

to Mr. K. Kobayashi for interpreting the pertinent parts 

of this document. 

2" Grateful acknowledgment is given Dr. J. Graw of 

Niirnberg for detailed information on this radiosonde, 

which is of his type H 50. 

119 
Radiosondes not Referred to in the Text 

312.801. Photostatic copy, 70 x 11 cm, of the record 

of a flight of a radiosonde of the National Bureau of 

Standards type. Presented in 1944 by the Plaskon Co., 

Inc., of Toledo, Ohio. 

312.802. Radio transmitter of a radiosonde of the 

National Bureau of Standards type. A plastic case 

7x9x 5 cm containing the radio circuit and a 

vacuum tube, type 1G6GT/G. Presented in 1944 by 

the Plaskon Co., Inc., of Toledo, Ohio. 

313,529. Balsa-wood box containing four radio tubes, 

small batteries, and some loose wire. Most probably 

an experimental apparatus. Transferred from the 

Weather Bureau in 1950. 

314,514. Radiosonde designed in Germany about 

1935 by Graw.^^^ In general principle similar to that 

of Duckert (MHT 313,527, figure 101), except that 

the pressure switch has a series of contacts in an 

insulating drum. Apart from the bimetal, which is 

in a plated shield 4 cm in diameter and 10 cm long, 

the mechanism and circuits are contained in a fiber 

box 10 cm in diameter and 15 cm long, with spun 

metal caps. Presented in 1954 by Mr. Kenneth M. 

Perry of Falls Church, Virginia. 

314,677. Variable-audio-frequency radiosonde. The 

white cardboard carton, 26 x 23 x 12 cm, bears the 

marks "Northeastern Engineering, Inc." and 

"U.S.W.B. Serial No. 509401," and has one side cut 

away to show the arrangement. There is a duct from 

the lower left to the upper right, in which the thermistor thermometer and the electrolytic hygrometer are 

held in bronze clips. The pressure switch is at the 

upper left, the batteries and the transmitter at the 

lower right. This instrument was found on 13 July 

1955, at Redwater, Alberta, and was transferred later 

in that year from the Weather Bureau. 

319,744. National Bureau of Standards type of 

radiosonde as made in 1940 for the Weather Bureau. 

Similar to MH T 322,315 (figure 112) except that 

the hygrometer is a flat "harp" of hairs. Marked 

"Sonde Track, Manufactured in U.S.A. by Washington Institute of Technology." Complete in its foilcovered carton, 25 x 11 x 21 cm. Presented in 1961 

by Mr. Edward L. Reilly of Washington, D.C. 

215 See Z«^i^- /"> Geophys., vol. 12 (1936), pp. 306-8. 

120 

319,824. Part of a British Meteorological Office 

radiosonde, marked "D698. " A somewhat earlier and 

possibly experimental version of MH T 322,313 

(figure 116). Transferred from the Weather Bureau 

in 1962. 

319,829. Part of the meteorograph of a Lang^— 

Reichsamt fiir Wetterdienst radiosonde, similar to 

M H T 322,311 (figure 103). Overafl dunensions, 

14 X 13 X 5.5 cm. Transferred from the Weather 

Bureau in 1962. 

319,831. Mechanical parts of the Blue-Hill radiosonde of 1936, similar to MH T 322,325 (figure 104), 

but with the aneroid chamber and its contact missing. 

Mounted on a white-painted board 20 x 10 x 1.2 cm 

that formed one wall of a box. It is marked "RMF . 

84," Transferred from the Weather Bureau in 1962. 

322,308. Time-cycle radiosonde marked "Simmonds 

Chronometer Radiosonde" and "P.B. 121. " A 

bimetal, an aneroid and a hair move contacts along 

a helix of the Lange type (see MH T 332,325, figure 

104). All the parts are mounted on an elaborate 

black plastic molding 23 x 12 cm, and protected by a 

thick insulating paper cover on each side. The hair 

and bimetal are in a shiny aluminum cylinder 6 cm 

in diameter and 15 cm long. The instrument is 

accompanied by a calibration chart. Transferred 

from the Weather Bureau in 1963. 

322,312. Another version of the Lang—Reichsamt 

fiir Wetterdienst radiosonde. No markings. Transferred from the Weather Bureau in 1963. 

322,314. National Bureau of Standards type radiosonde in carton 22 x 11 x 20 cm, covered with smooth 

paper, now yellowed. Two flaps open to reveal an 

aluminum tube 6 cm in diameter and 16 cm long, 

containing a thermistor and an electrolytic hygrometer element. An aneroid barometric switch, a 

radio transmitter, heat insulation, and batteries 

occupy the rest of the carton, which is marked 

"Diamond-Hinman Ray Sonde Mfgd by Julien P. 

Friez & Sons Division of Bendix Aviation Corporation Baltimore, Maryland U.S.W.B. 1943." Transferred from the Weather Bureau in 1963. 

322,316. A radiosonde of the time-cycle type, 

seriously damaged. It is unmarked, but a tag reads 
"Longine." It has contacts as in the GALCIT instrument, MH T 319,828 (see page 108) and includes a 

cork battery box between a radio transmitter and a 

meteorograph, the latter having rather elaborate 

radiation shields. Transferred from the Weather 

Bureau in 1963. 

322,320. Friez's attempt to mount a time-cycle radiosonde in the sort of foil-covered carton used for the 

Diamond-Hinman instrument (see number 322,322 

below). The linkage from the bimetal is complicated. 

There are two "harps " of hair, their deflections being 

added. The carton is marked "Olland System Ray 

Sonde. Julien P. Friez & Sons Baltimore." Transferred from the Weather Bureau in 1963. 

322.322. A variable-audio-frequency radiosonde 

marked "Diamond-Hinman Ray Sonde, Mfgd by 

Julien P. Friez & Sons Division of Bendix Aviation 

Corporation Baltimore, Maryland." This has the 

electrolytic thermometer and two "harps " of hair, 

the changes in length of which are added by a lever. 

Two concentric radiation shields. Carton 24 x 11 x 21 

cm. Transferred in 1963 from the Weather Bureau. 

322.323. Radiosonde in two foil-covered cartons, of 

which the larger, 17 x 10 x 20 cm, contains the 

batteries, transmitter, and aneroid pressure switch. 

The smaller, 10 x 10 x 20 cm, contains three concentric 

aluminum tubes enclosing an electrolytic thermometer 

and two "harps " of hair arranged so that their 

changes in length are added and operate a variable 

resistor. The smaller carton is labeled "Meteorograph 

Friez Baltimore U.S. Pat. No. 2,027,367." Transferred from the Weather Bureau in 1963. 

324.236. Radiosonde, externally similar to MH T 

324,240 (Figure 114), of which it seems to be an 

earlier model, using a vacuum-tube transmitter. 

The pressure switch, the contact strip of which is 

made by using printed-circuit techniques, is similar. 

The shield for the temperature and humidity elements 

is missing. Marked "AN/AMT 11 .. . Molded 

Insulation Co. Serial 1675." The thermistor is supplied 

in a protective vial. Transferred from the Weather 

Bureau in 1964. 

324.237. A Japanese radiosonde, similar to MH T 

319,826 (figure 118), but having two mercury 

thermometers. The battery is missing, but the 

instrument seems otherwise complete in its white 

corrugated carton and is marked "CMO-550L. " 

Serial number 4352. Transferred from the Weather 

Bureau in 1964. 

324.238. Variable-audio-frequency radiosonde. Internally similar to MH T 324,236 above, but the outer 

case, 15.0 x 12.5 x 12.0 cm, is made of corrugated 

cardboard with a shiny white surface. It is fitted with 

an antenna rod 38 cm long and a strap of webbing 

for the attachment of a battery box, which is missing. 

There is a calibration sheet for the pressure switch. 

Presented by the Weather Bureau in 1964. 

121 
FIGURE 120 

Diagram of a station meteorograph or "triple register." (From U.S. 

Weather Bureau Gircular D, 2d ed., 1900, figure 19.) 

FIGURE 121 

MHT 316,287. Station meteorograph similar to the "triple register" 

(MHT 308,205), but some of the pens and magnets are duplicated, so 

that it could make two complete sets of records of wind speed and wind 

direction. The drum is lengthened to 31.5 cm and the cast-iron base 

measures 74 x 45 cm. There is a hinged cover, glazed on all sides and on 

the top. A few small parts are missing. The instrument is marked "U.S. 

Weather Bureau Duplicating Triple Register No. 1." Transferred from 

the Weather Bureau in 1959. (Smithsonian photo 61904-C.) 

122 
Chapter 11 

Miscellaneous Meteorological Instruments 

I n this chapte r ar e collected a small numbe r of 

instruments tha t d o not fit into the categories 

dealt with in the earlier chapters of this catalog. 

Combination Recording Instruments 

T h e recording instrumen t is fundamentally a 

labor-saving device, an d America n ingenuity in 

the construction of such things has naturally led 

to a predilection for meteorological recorders. For 

half a centur y after abou t 1885, man y of the 

stations of the Weathe r Bureau and the Signal 

Corps ha d their sunshine, rainfall, an d wind 

recorded on a "tripl e register," sometimes called 

a "quadrupl e register " because it recorded both 

the direction an d speed of the wind as well as the 

rainfall an d sunshine, all on one large drum.^^e 

T h e Museu m ha s two of these, MH T 308,205 

and MH T 314,711 (see also figure 120). 

M HT 308,205. A station meteorograph or 

"triple register" was used by the Weather Bureau 

for making records of wind, sunshine, and rain. 

On the heavy cast-iron base, 58 x 45 cm, is a brass 

label that reads "Julien P. Friez & Sons, Belfort 

Observatory, Baltimore, Md., U.S.A." Electromagnets operate pens for wind speed, rainfall 

and sunshine, and four printing points, with an 

inking device, record the direction of the wind. 

The wind direction and the sunshine are recorded once a minute through a contact on the 

clock that drives the drum, which is advanced 

axially by a screw of large pitch while it is rotating. 

The same magnet is used for sunshine and rainfall, and this has an ingenious ratchet and cam 

that gives a zigzag trace, five steps to the right 

and then five to the left. There are three small 

bottles of ink of different colors. Transferred 

from the Signal Corps in 1923. 

MHT 314,711. Station meteorograph or "triple 

register," similar to MH T 308,205 except that 

the cast-iron base is 60 x 47 cm, and the brass 

label reads "U.S. Weather Bureau Triple 

Register No. 144 Julien P. Friez Baltimore, 

Md. " Transferred from the Weather Bureau in 

1955. 

T h e instruments which provided the electrical 

impulses were the cu p anemometer,^^^ the wind 

vane,^^^ the tipping-bucket rain gauge,^^^ and the 

Marvi n sunshine recorder.^^" 

2i« See U.S. Weather Bureau, Instructions jor . . . wind 

measuring and recording apparatus, Circular D, Instrument 

Division, 2nd ed. (1900), p. 44. 

217 See p. 87 and item MHT 230,001 on p. 86. 

218 See p. 80, item MHT 315,906. 

219 See p. 74, item MHT 314,713. 

220 See p. 90, item MHT 308,176. 

299-340 O—69-

123 
FIGURE 122 

MHT 327,633. Thermo barograph. Combined aneroid barograph and 

bimetallic thermograph recording with two pens on one chart. The 

barograph has eight aneroid chambers in series. The thermograph has 

a bimetallic coil of 3% turns, 2.0 cm in diameter. Inscribed. "Tycos 

Stormograph Reg.** U.S. Pat. Off. Short & Mason London Made in 

Gt. Britain." The clock, which is in the drum, is inscribed "Pat. 3715.02 

Made in Germany for Taylor Instrument Companies 7 jewels." Overall 

dimensions of case, 37 x 21 x 22 cm. Presented in 1966 by Rutgers 

University. (Smithsonian photo 61906-D.) 

The Museum also has the first, and very likely 

the only example of a station meteorograph that 

furnished, besides a rainfall and sunshine record, 

two complete records of wind speed on one drum 

(MHT 316,287, figure 121). The purpose of 

this can only be surmised. 

After the Richard firm standardized their light 

and simple recording instruments, it was quickly 

realized that more than one element could be 

recorded directiy on one drum. The Museum 

specimen is English, with a German clock 

(MHT 327, 633, figure 122). 

Other Instruments, Not Classified 

It was noted in chapter 3 that the system of 

telemetering developed in the 1880s by the firm 

of Richard could be applied to the distant indication or recording of the readings of any instrument that can move a pointer. The Museum has 

124 
FIGURE 123 

MHT 314,537. Receiving station of a telemeter for one of various 

meteorological elements. On the standard Richard clock drum, 9.2 cm 

diameter and 13 cm long, there is a 7-day chart graduated from —26 

to -|-115, presumably °F. The glass-fronted mahogany case, 38 x 17 x 

21 cm high, bears a label engraved "Thermometre enregistreur Anc"® 

M°° Richard Freres, Jules Richard, Succ"^ Constructeur Brevete S. G. 

D. G. 25, Rue Melingue, 25 Paris." The trademark of the firm and the 

number 44938 are stamped on the brass baseplate. A tag says "Tele 

Register 44938 from Exposition at Seattie Wash." [1909?] Transferred 

from the Weather Bureau in 1954. (Smithsonian photo 61910.) 

125 
L/^ 

0 jehlc^i'?yh ' f9^o 

"^^ 7 . in e/i/y'i^ o yy-i e HA-

\ 

2 

0 

h 

s 

6 

7 

i 

IO 

n 

U 

)'b 

. '"1 

K 

• U 

7 

n 

f^ 

V. • 

7hu*tc 

6 

1 

6x' 

du/n. 

^/^*>~ 

* W J 

f i a 

flMVi^ 

(3(MC 

J^ 

Jc^^f 

//, ^ 

/?«M'; 

X.^ 

uiY 

xmv 

• 

- j 

- '• ' . 

~ 

•'•'- '••' 

- • : 

' 

foe 

FIGUR E 

-j 6-L \i>ii 

1 " 

1 ^* i ^^ 

1 i-2 i * * 

f X- <''-^' 

' m 

*• 

* i 

7* 

3 

J ^ 

7^ 

<r 

<7 

9 

«.** 

(j •} OA^'^'^t-'^^-^ • 

. 

It 

_;j i"--* 

^^ i 1 ^^ 

^ ' 

1^6 4 » 1 i t <« . 

^s- 7<rj;/ 

7 / . j-^ j a, 

^/, 

yi J" 1 j ^ [ St! 54; /•;• 

ji -l^ 

7^'^ 79 

)o \y^ 

y. J^ 

7ii }l> 

'" // 

'^'/^ 

yo • ; f 1 

i 

^^ !7 3 

• ^>^ t^-^ 

y/^ . i r j > 

("</>' 

/;.•./. . 

/"v,, , 

:':...-, 

{ -

1 2 4 

^ ^ \ 

v^ j X* ! w^ 1/ ^ 

S^ U * t >/ 

*5'^ i/^ 1/^ 

ty-t 

j « -

9 

"iOfe 

1 

1 

le - Jtf6 

^« 

> 

3 0 ~ 

. 

\ 

,^^-xs^^^ ' 

7o- !• - iy'J{^^^icL^ yJ^.^ 

•i7-»t*;y-» 2^ t.'?/>• f V;-y / 

- f -4r -

1 

3<. / j -s-^ 

5 ^ ~ 

9o 

30 (fp 

7 c 

5 0 

y. /o 

1 

/4' || i4>-/ 1 J»J'' 

^^ f. 1 , \.. 

^y\S(^'^ ^^\^/ 

i i ' 

^7/^,^ 1 < 

;^ j s^; 7^ ' 7 / 

^ fi ^ ; fz i/ 7 

^^ ^'75-/^ 

'1 

>8 

^C 

1 / 

•^7 4^ 1 .vz j 

;4 ' ^ ^"-^ 

•'^ ; '>^ 'f-r" 

^ ' SZ r x 

>. V/j ^ 

>^ :^ ^ 

0 V ' < ^ 

1 

1 1 1 

/ o 

4t 

<3 

1 I 

^i,-

5o 

?o 

^ ^« ^ I I . 1 1 1 <^ir»« ^VA^ 

j3^oa^-^^-—^— -_ «*-. - • 

-^0 1 Icj ; ^-^ 

1 

; r, ,o-'. ' •'\ -yoj. 

^= fl >. / 

3* 7f»'>»./» 

7^'/J * '-

\j' i? - j ' ^ 

j ^ 1 

i - - ' "~ 

' 1 \ 

T,9 U\'>»li>\ '^O'/l » 

}<;•) 1 ;><:' -

1 

i 

^,^ 1 >^ j 

}j^t 

^ / 

2? n* 

^ 1 

. ,, 1 

"io / 

y*,r 

iv^.^, ^y(/'^'^;^>^ 

3o / t^.-w C^ ^ -i ^ f '1 ^ 

3o jz^^^ ^t^?^^ ^ '/j ^ 

, 

" 

^^ 

>" 

^1'/ / 

1 •> 

I - . . », • 

A./ j ,>C.. .J-,... .. 

>• ^^.,^/,Zi. 2 .f'iL^^ . 

'9 A^j/^-\' y-'^- f-f-r 

t9-c^t '>y9-'>'^ 

1 1 

V- 1 }c :-)<' 

1 ! 

^y-/? 

1 

. 1 

1 

7^fS -t' — '"•^ '-''•' V -

•^'v"^'- ^ 

Weather record from Georgetown in 1835. 

(Smithsonian photo 61908-B.) 

126 
a telerecorder (MH T 314,537, Figur e 123) of this 

kind, which was evidentiy used to record temperature , bu t is pu t her e to emphasiz e the versatility 

of this apparatus.^^^ Th e modus operandi of this 

instrument is substantially the same as tha t of the 

telemeter discussed in chapte r 3.^^^ 

T h e Museu m also has three examples of the 

"storm glass" or "chemica l weathe r glass," which 

are scarcely serious meteorological instruments, 

b u t ha d a wide popula r distribution for man y 

decades. This instrument was simply a sealed 

glass tub e nearly full of a saturated solution of 

some crystalline substance, with a n excess of the 

solute, so tha t the quantit y of crystals to be seen 

in the tub e is a function of the ambien t tempera -

ture. Needless to say, its value as an indicator of 

coming weathe r is nonexistent.^^^ Th e three examples, each mounte d beside a thermometer, are 

M H T 322,298; 322,300; 327,559. 

M HT 322,298. "Chemical weather glass" and 

thermometer, mounted in a wooden frame 

22 X 8 cm, in front of a paper scale, marked 

"Standard Barometer" and "Chas. E. Large 

Brooklyn, N.Y." The chemical weather glass 

is a tube 17 cm long and 1.2 cm in diameter, 

filled with an amber-colored liquid containing 

brownish crystals. The thermometer, 15 cm 

long and filled with red spirit, has a scale 

running from —10 to +12 8 [°F]. On the back 

of the frame is a printed sheet of instructions. 

Presented in 1963 by Mr. Silvio A. Bedini, 

Washington, D.C. 

M HT 322,300. "Chemical weather glass" and 

thermometer. They are similar to MH T 

322,298 above in general appearance, except 

that the thermometer scale is of brass and is 

^^ See Richard Freres, Notice sur les instruments enregistreurs . . ., 3d ed. (Paris, 1889), pp. 58-9. 

222 See p. 53. 

223 See Sir Graham Sutton, Weather, vol. 20 (1965), pp. 

270-271. Some such tubes contain camphor, potassium 

nitrate, and ammonium chloride, in a mixture of alcohol 

and water. 

marked "J. A. Pool, Manufacturer, Oswego, 

N.Y.," and that the "weather glass" is 1.5 cm 

in diameter. The mahogany frame measures 

23 X 8 X 1.8 cm. Presented in 1963 by Mr. 

Silvio A. Bedini. 

MHT 327,559. Glass tube, 22 x 1.5 cm, and a 

thermometer graduated from —32 to -j-55° R, 

mounted side by side on a wooden board 

32 X 9 X 1 cm, inscribed "Baroskop." There 

are 22 inscriptions in Danish near the glass 

tube, which contains a clear liquid and some 

brownish crystals. The board is riddled with 

worm holes. Received in 1966. 

T h e Museum's collections include a shelter for 

thermometers and other instruments: 

MHT 308,179. Instrument shelter of the Signal 

Corps type, of white-painted wood, 77 x 83 x 52 

cm, with louvered sides and back, and a double 

roof. For some reason it has been encased in 

glass panels, the louvered front having been 

removed entirely and replaced by a sheet of 

glass. There is a metal label reading "Instrument Shelter Type ML 41 Serial [blank] 

Signal Corps U.S. Army Order No. 110441 

Date May 28, 1923." Transferred from the 

Signal Corps in 1923. 

MHT 308,180. Wooden stand for MH T 308,179 

above, painted white and 122 cm high. Transferred from the Signal Corps in 1923. 

Finally, although it is not an instrument, a n 

honorabl e place must be found for a 5-year 

weathe r record (MH T 317,028) kept by the 

Reverend Jame s Curley in Georgetown nea r 

Washington mor e tha n a century an d a quarte r 

ago. Figur e 124 shows a page of his record book. 

MHT 317,028. Meteorological register of 

weather data. An observation book kept by 

Rev. James Curley of Georgetown College, 

Washington, D.C, from 1835 to 1840. He 

observed the thermometer and barometer at 

6, 9, and 12 A.M. and 3, 6, and 9 P.M., and also 

made remarks on the state of the weather. 

Presented in 1960 by Georgetown University. 

(Smithsonian photo 61908-B.) 

127 
128 

Bibliography 

ABBE, CLEVELAND. Treatise on meteorological apparatus and methods. U.S. War Department, Annual Report of Chief Signal Officer for 1887, part 2. Washington, 1887. 

KLEINSCHMIDT, E. , ed. Handbuch der meteorologischen Instrumente und ihrer Auswertung. 

Berlin: Springer, 1935. 

KuRTYKA, JOHN C. Precipitation measurements study. State of Illinois, State Water Survey 

Division, Report of Investigation no. 20. Urbana, Illinois, 1953. This has 193 

figures and 1,079 references, but not all the latter have been verified; therefore, 

this valuable compilation should be checked with care by any researcher. 

LIVINGSTON, GRACE J. Annotated bibliography of evaporation. Washington: U.S. Weather 

Bureau, 1909. 

Manual of radiosonde observations {WBAN). (U.S. Department of Commerce, Weather 

Bureau, Gircular P.) 7th ed., June 1957. 

MIDDLETON, W . E . K . The history of the barometer. Baltimore: The Johns Hopkins Press, 

1964. 

. A history of the thermometer and its use in meteorology. Baltimore: The Johns Hopkins Press, 1966. 

. Meteorological instruments.ToTonXo:\Jn\v&:&\XYoiTovonto Press, 1941; 2d ed., 

1943; 3d ed., 1953, revised and enlarged by A. F. Spilhaus. 

The invention oj the meteorological instruments. Baltimore: The Johns Hopkins 

Press, 1968. 

NEGRETTI & ZAMBRA. A treatise on meteorological instruments: explanatory oj their scientific 

principles, method of construction, and practical utility. London: Negretti & Zambra, 

1864. 

PERLAT, A. , and PETIT, M . Mesures en mitiorologie. Paris: Gauthier-Villars, 1961. 

Uber Radiosonde-Konstruktionen. Denkschrift. Berlin: International Meteorological 

Organization, Aerological Commission, 1937. Also a Nachtrag, Berlin, 1939. 

WAARD, CORNELIS DE. Uexperience barometrique, ses antecedents et ses explications. Etude 

historique. Thouars Imprimerie Nouvelle, 1936. 

WEXLER, ARNOLD, ed. Humidity and moisture. Measurement and control in science and industry. 4 vols. New York: Reinhold, 1965; and London: Chapman & Hall, 1965. 

See especially volume 1. 

U.S. GOVERNMENT PRINTING OFFICE: 1969 O-299-34 0