DEPARTMENT OF THE INTEBIOK

WATER-SUPPLY

IRRIGATION PAPERS

UNITED STATES GEOLOGICAL SURVEY

No. S

WINDMILLS FOR IRRIGATION. MURPHY

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1897
IRRIGATION REPORTS.

The following list contains the titles and brief descriptions of the principal reports 

relating to water supply and irrigation prepared by the United States Geological 

Survey since 1890:

1890.

First Annual Report of the United States Irrigation Survey, 1890, octavo, 123 pp.

Printed as Part II, Irrigation, of the Tenth Annual Report of the United States Geological Survey, 1888-89. Contains a statement of the origin of the Irrigation Survey, a preliminary report on the organization and prosecution of the survey of the arid lands for 

purposes of irrigation, and report of work done during 1890.

1891.

Second Annual Report of the United States Irrigation Survey, 1891, octavo, 395 pp.

Published as Part II, Irrigation, of the Eleventh Annual Report of the United States 

Geological Survey, 1889-90. Contains a description of the hydrography of the arid region 

and of the engineering operations carried on by the Irrigation Survey during 1890; also 

the statement of the Director of the Survey to the House Committee on Irrigation, and 

other papers, including a bibliography of irrigation literature. Illustrated by 29 plates and 

4 figures.

Third Annual Report of the United States Irrigation Survey, 1891, octavo, 576 pp.

Printed as Part II of the Twelfth Annual Report of the United States Geological Survey, 1890-91. Contains a report upon the location and survey of reservoir sites during the 

fiscal year ending June 30,1891, by A. H. Thompson; "Hydrography of the arid regions," 

by F. H. Newell; "Irrigation in India," by Herbert M. Wilson. Illustrated by 93 plates 

and 190 figures.

Bulletins of the Eleventh Census of the United States upon irrigation, prepared 

by F. H. Newell, quarto.

No. 35, Irrigation in Arizona; No. 60, Irrigation in New Mexico; No. 85, 

Irrigation in Utah; No. 107, Irrigation in Wyoming; No. 153, Irrigation in 

Montana; No. 157, Irrigation in Idaho; No. 163, Irrigation in Nevada; No. 

178, Irrigation in Oregon; No. 193, Artesian wells for irrigation; No. 198, 

Irrigation in Washington.

18952.

Irrigation of western United States, by F. H. Newell; extra census bulletin No. 

33, September 9, 1893, quarto, 22 pp.

Contains tabulations showing the total number, average size, etc., of irrigated holdings, 

the total area and average size of irrigated farms in the subhumid regions, the percentage 

of number of farms irrigated, character of crops, value of irrigated lands, the average cost 

of irrigation, the investment and profits, together with a resume of the water supply and 

a description of irrigation by artesian wells. Illustrated by colored maps showing the 

location and relative extent of the irrigated areas.

1893.

Thirteenth Annual Report of the United States Geological Survey, 1891-92, Part 

m, Irrigation, 1893, octavo, 486 pp.

Consists of three papers: "Water supply for irrigation," by F. H. Newell; "American 

engineering and engineering results of the Irrigation Survey," by Herbert M. Wilson; 

" Construction of topographic maps and selection and survey of reservoir sites," by A. H. 

Thompson. Illustrated by 77 plates and 119 figures.

A geological reconnoissance in central Washington, by Israel Cook Russell, 1893, 

octavo, 108 pp., 15 plates. Bulletin No. 108 of the United States Geological 

Survey; price, 15 cents.

Contains a description of the examination of the geologic structure in and adjacent to 

the drainage basin of Yakima River and the great plains of the Columbia to the east of 

this area, with special reference to the occurrence of artesian waters.

1894.

Report on agriculture by irrigation in the western part of the United States at the 

Eleventh Census, 1890, by F. H. Newell, 1894, quarto, 283 pp.

Consists of a general description of the condition of irrigation in the United States, the 

area irrigated, cost of works, their value and profits; also describes the water supply, the 

value of water, of artesian wells, reservoirs, and other details; then takes up each State 

and Territory in order, giving a general description of the condition of agriculture by irrigation, and discusses the physical condition and local peculiarities in each county.

Fourteenth Annual Report of the United States Geological Survey, 1892-93, in two 

parts, Part II, Accompanying papers, 1894, octavo, 597 pp.

Contains papers on " Potable waters of the eastern United States," by W J MeGee; 

"Natural mineral waters of the United States," by A. C. Peale; "Results of stream 

measurements," by F. H. Newell. Illustrated by maps and diagrams.

(Continued on third page of cover.)
DEPAETMBNT OF THE INTEEIOE

WATER-SUPPLY

AND

IEEIGATION PAPEES

OF THB

UNITED STATES GEOLOGICAL SURVEY

ISTo. 8

WASHINGTON

GOVERNMENT PRINTINGS OFFICE 

1897

UNITED STATES GEOLOGICAL SUEYEY

CHAELES D. WALCOTT, DIRECTOR

WINDMILLS FOR IRRIGATION

EDWARD CHAELES MUEPHY

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1897

CONTENTS.

Introduction ........,._....-----.....-....-..---_.--...__........_....-_. 9

Wells near Garden, Kansas. _-__-..,___-____.___--___.-________.__..,___--__ 10

Pumps_________.___.-__-------..__--__-.-.---...-_...-_---__---_..----- 10

Instruments and methods.._.__..__-________..____.__--___-___-.__.-._--.__ 12

Description of mills tested........._..._,............ ________________ 14

"Mill No. 1....... .. .--__.___ _ ........................ 14

Mill No. 2-....................................................... 14

Mill No. 3..--. __ _ .. _____-__-.-_. .-_. 16

Mill No. 4.._ __ .._-__. ___.___-...-.._ .. - ___- 17

MU1 No. 5..................:......-....-..........--.-... .. 18

Mill No. 6.............-.........-.....-.......-..........-.. .. 19

Mill No. T........................................................ 20

Mill No. 8....- _ .. ..._- __ . _..___.-. - 20

Mill No. 9.__.._.- ._ __.__-_.___.. ._._._._ . .. 22

Mill No. 10..................................................... 22

Mill No. 11............ ......_...................._.............. 23

Mill No. IS....................................................... 24

Mill No. 18......... ...---.-._---_.---.. .-.- __ .--. 35

Mill No. 14_.-_---.--_----..-_-.---__._-.---- _ .._ _- 25

Mill No. 15.-...--.-_------_.--.:---.----.---..---.---I......--._. 25

Mill No. 10..--.--.-..........-.......;--......................... 26

Mill No. 17--.--...-......--.--..........-.-.-..-__-...-------.. 26

Mill No. 18...-..... __........ --...-...--. .--- -.--. 27

Mill No. 19--....-...-.-....-- ..-.-..---..--.-........--.-......- 27

Mill No. 20...-----.--..-.-.- ........ .--.- .....--...--.._-.-- 28

Mill No. 21_.....-..--_.-.-----..---.......-..----.---....-....... 29

Mills Nos. 23 to 34....-----.--..-.-....--.-----.----._..--......-. 30

Mill No. 25-..--.-------.--.---.-..--.-..--- . ._ .. ..__ 30

Mill No. 26-....-.----......---.-.----.-.----..--..---.---.---.- 31

Mill No. 27-....-..--.-. . -..- ._---- .__._ 32

Discussion of the results.-.. -.-............--..,...--..--...--.---..--..-- 32

Relation between wind velocity and strokes___..___.___._____-..-- 35

Useful work in horsepower..... --.__..--._-.._ __--._----_--_-_ _ 35

Comparison of back-geared and direct-stroke mills..--......-----.--... 37

Pump load due to well point. -. -.---.-.-----.--.---.-..-.-.----.------ 38

Useful work done in a given time.-.-..-------.--..---.-.-..-- _.-... 39

Power mills.............-.--.-..--._---..-.._---.-.-...--.......----. 40

Total energy of the wind............................................... 44

Efficiency of mill..--..-.-..----.--..-------.--...----,.--------------- 45

General conclusions...... ...-...-...--...-_-..-.. .----.-..---.........--- 46

Index .....-..-...---.--.------_----.--------- -.,.-------. ----...-.--.-- 49

5
ILLUSTRATIONS.

Plate I. View of Mill No. 2, Woodmanse, and anemometer.--- 14

II. View of Mill No. 3, Aermotor------- .............................. 16

III. View of Mill No. 4, Ideal, and No. 5, Aermotor................... 18

IV. Working parts of Mill No. 6, Gem.............. ................ 20

V. View of Mill No. 12, Ideal......._._..............._.-......... .. 24

VI. View of MiU No. 13, Aermotor-..-............................... 26

VII. View of MillNo. 19, Gem.--.-..-----.--......................... 28

VIII. View of MillNo. 21, Halliday......... .......................... 30

Fig. 1. View of Gauge pump......-.--.---.--.----.--.-.-........ -------- 10

2. Working parts of Woodmanse MoguL._----..-.....--._-_-._--.-- 11

3. Sectional view of Woodmanse pump.. -.....-...-........-----.---. 12

4. Diagram showing results with Mill No. 2..........-....--...-...... 14

5. Working parts of Aermotor.._-.-..--.--------..------------- _..,.- 15

6. Stone pump...... ____.___.____. -_.. _.__ _.---.--.---.- -- 15

7. Valves of Stone pump.......--------....-._------...---.---------- 16

8. Diagram showing results with Mill No. 3........................... 17

9. Diagram showing results with Mill No. 4. ^........................ 18

10. Diagram showing results with Mill No. 5_.....,.........-.-.---.-. 19

11. Diagram showing results with Mill No. 9, Aermotor_.____-_--.--.. 20

12. Working parts of Mill No. 10, Ideal.--.-.-------------------------- 21

13. Diagram showing results with Mill No. 11, Ideal_.._.___-__._.._.-- 22

14. Working parts of Frizell cylinder. _,_.______.-____.__-_. ....-..--.. 23

15. Diagram showing results with Mill No. 12.__-____.__.-_--.,--.-_.- 24

16. Diagram of results with Mill No. 19. ____...___.__._-...-__,-. .... 25

17. View of Mill No. 20, Jvaibo....................................... 26

18. Diagram showing results with Mill No. 20-........-----.-..--...._ 27

19. Working parts of Halliday Mill-..-..-...-.-.-.--....----..-.-..-. 28

20. Diagram of results with Mill No. 21...............-----.--.......- 29

21. Workingpartsof Power MillNo. 26-......--..--..-------.---..-.. 30

22. Workingparteof Power MillNo. 27--..- ---------.------ ---- 31

23. Foot gear of power Mill No. 27.-.--.-------.-----.-.-....-----...- 32

24. View of Defender mill and elevator...................... .......... 33

25. Diagram showing relation between horsepower and wind velocity

for five 12-foot mills.....-.. ................................. 36

26. Diagram showing relation between horsepower and wind velocity

for four 8-foot mills.--_..-...-----. ----.-------------------.-.- 37

27. Diagram showing useful work for different loads of Mill No. 27...._. 42

28. Diagram showing horsepower for different loads of Mill No. 27...... 43

29. Diagram showing relation between number of revolutions of brake 

pulley per minute and load for different wind velocities for Mill

No. 27... . . . ... . . .... ...... 44

30. Diagram of forces acting on vane of mill.........._.._..___.....__ 47

6
LETTER OF TRANSMITTAL.

DEPARTMENT OF THE INTERIOR, 

UNITED STATES GEOLOGICAL SURVEY,

DIVISION OF HYDROGRAPHY,

Washington, April 13, 1897.

SIR: I have the honor to transmit herewith a manuscript entitled 

Windmills for Irrigation, by E. C. Murphy, professor of civil engineering in the University of Kansas, at Lawrence. This gives the 

results of experimental tests carried on during the summer of 1896 

upon windmills located for the greater part in the vicinity of Garden, 

Kansas. These results are presented in condensed form for early 

publication in order that they may be available for use and discussion by persons interested in the matter. They should be considered 

as preliminary to a more popular presentation, which, however, can 

be given only when a considerable number of experimental measurements of various kinds have been completed and a careful study yielding general conclusions has been made.

In detailed work of this character it is impossible to avoid technical 

discussions and mathematical formulas, but as far as possible the 

results of the tests have been expressed in graphic diagrams. A careful study and comparison of these and of the accompanying descriptions shows the difference of behavior of the mills examined under 

the conditions in which they were found. It is, of course, impossible 

to draw conclusions applicable to all mills from the examination of a 

few, but the facts here shown are significant and worthy of careful 

consideration.

Very respectfully, F. H. NEWELL,

Hydrographer in Charge. 

Hon. CHARLES D. WALCOTT,

Director United States Geological Survey.

1

WINDMILLS FOE IRRIGATION.

BY E. C. MTJRPHY.

INTRODUCTION.

The windmill has long been employed to perform mechanical work. 

Just when and where the first windmill was used is not definitely 

known, but we know that a considerable number were utilized in 

France in the twelfth century. They were employed in Holland in 

the fifteenth century in pumping surface water over the dikes into 

the sea. It is not the purpose of this paper, however, to trace the 

history 1 or development of windmills, but to present the results of 

some recent measurements on the useful work windmills are doing, 

especially when employed to pump water. It is surprising to note 

how little definite information there is in regard to the efficiency of 

windmills, especially of the steel back-geared mills of the present day. 

Thousands, perhaps hundreds of thousands, are in use doing work of 

various kinds, and yet very few careful measurements have been 

made to determine their horsepower or the number of foot-pounds of 

work they are accomplishing under different velocities. It was to 

supply in a measure this lack that in 1895 the writer undertook to 

measure, with instruments then at his disposal, the pumping power 

of windmills. In 1896, with much better facilities, he continued this 

work, extending it to include power as well as pumping mills. The 

attempt was not made to measure the power of every make of mill; 

that was impossible. It was thought best to confine the work to 

different sizes of the standard mills, those that are used to a large 

extent and are giving satisfaction. In some cases two or three tests 

of the same size and make of mill were made for the purpose of showing the influence of the pump or well on the useful work done.

Perhaps nowhere in the United States is irrigation from wells by 

the use of windmills so extensively practiced as in the vicinity of 

Garden. Here are found hundreds of windmill pumping plants, irrigating from 1 to 15 acres, the pumps lifting from 3 to 14|- quarts per 

stroke to a height of from 10 to 45 feet. Here are found the large steel 

mills, with the latest improvements, running day and night whenever

1 The Windmill as a Prime Motor, by Alfred R. WolflE, 1890, chapter 3, contains an account of 

the early history of windmills.

9
10 WINDMILLS FOR IRRIGATION.

the wind velocity is sufficiently great. These reasons induced the 

writer to select this locality as the field of his investigations.

WELLS NEAR GARDEN, KANSAS.

A brief description of the water supply and the wells of this locality 

may assist in conveying an understanding of what follows. The water 

is found in sand and gravel at distances below 

the surface varying from 8 to 40 feet. This 

material is in layers of variable thickness and 

different degrees of coarseness, ranging from 

fine sand to large gravel. It is overlain by a 

layer of sandy clay, which in some places will 

stand vertical for years without any support. 

In other places there is very little clay in this 

layer. The wells are usually 3 to 4 feet square, 

and cased with wood through the top sandy 

clay to the water-bearing sand; then a wood 

or galvanized-iron casing from 12 inches to 3 

feet in diameter extends down from 8 to 20 feet 

into the sand to a layer of gravel. Where this 

latter casing is large, three or more galvanizediron pipes 6 to 12 inches in diameter are put 

down in the bottom of it, and these sometimes 

have wire gauze over their tops to keep down 

the sand. These galvanized-iron pipes have 

perforations about one-fourth inch in diameter 

for a distance of 2 feet or more from the bottom for letting in the water. In many cases 

instead of this small open well the supply pipe 

is on a well point whose diameter is the same 

as that of the supply pipe, and whose length 

varies with the diameter. These well points 

have not given satisfaction, and are being replaced by the open well.

The difficulty with many of the wells is that 

they are not large enough; the water in them 

is lowered too rapidly, producing such a rapid 

inflow as to carry sand, which cuts the valves 

and cylinder lining.

FIG. 1. View of Gause pump.

N, plunger; B, spout; F, discharge pipe; L, flange for 

platform; H, plunger; T, cylinder; Z, enlarged valve opening and check valve; S, suction 

pipe. PUMPS.

Nearly all the pumps in use in this vicinity with windmills are 

of the reciprocating-piston type. Fig. 6 shows what is called the 

Stone pump, manufactured by R. G. Stone, of Garden. They are 

made in three sizes 6-inch, 8-inch, and 10-inch, these dimensions being the approximate diameter of the discharge pipe. The
MTJBPHY.] WOODMANSE MOGUL. 11

diameter of the cylinder is less than this by twice the thickness of 

the brass lining. The valves shown in fig. 7 are of the latest form;

FIG. 2. Working parts of Woodmanse Mogul.

the plunger valve is of the single-flap or clack form, and the check 

of the disk form, made so the water can pass tip in the center as well
12 WINDMILLS FOE IRRIGATION. [NO. 8.

as around the sides. In an earlier form of this pump the plunger 

valve is of the double-flap or butterfly form, and the check of the 

lift form, but having no opening at the center. Probably nine-tenths

of all the pumps in use near 

Garden are of the Stone variety. Fig. 1 shows the Gause 

pump, one of the first used 

there for irrigating purposes. 

It is more expensive than the 

Stone, and is not so much 

used now. Fig. 14 shows cylinder of 8-inch Frizell pump, 

a few of which are in use. 

Fig. 4 shows the Woodmanse 

pump, which is used with 

windmill No. 2. Fig. 24 

shows a crude home-made 

pump called the "water-elevator." One of these is in 

use in Garden.

INSTRUMENTS AND 

METHODS.

The wind velocity was measured with a United States 

Weather Bureau cup anemometer. Each mile of wind 

was recorded electrically by 

one pen of a two-pen register. By means of a little 

device fastened to the pump 

an electric circuit is closed at 

each stroke of the pump and 

a record made by a recorder. 

Another electric circuit leading from the recorder to the 

other pen of the register 

is closed at each hundred 

strokes of the pump, and a 

record made on the register; 

hence the graphic record of 

the register shows the number of miles of wind in any 

given time, and also the number of hundred strokes of pump in the same time. 

The anemometer was held on a pole at the height of the axis of the

PIG. S. Sectional view of Woodmanse pump.
MUBPHT.] INSTRUMENTS AND METHODS. 13

wheel of the windmill. The pole was made so that its length could 

"be increased at will from 25 to 50 feet. The anemometer on the pole 

is shown in Pis. I and VIII.

The discharge per stroke of the pump was found by catching the 

water for several strokes in a tub and measuring this with a quart 

measure. This was found to vary with the number of strokes per 

minute in a few cases on account of the valves leaking. The discharge 

given where it varied is for nearly a maximum speed of pump. The 

lift or distance from the surface of water in the well to the center of 

the water column as it leaves the discharge pipe was measured when 

the pump was working quite rapidly. For pump on well points it 

was estimated from the depth to water when the point was put down, 

making an allowance for the pumping down of the water.

In the following pages descriptions are given of each of the mills 

tested, these "being illustrated by a few photographs of the mills and 

surroundings and by drawings of the common form of pumps employed. 

The descriptions are also accompanied by diagrams showing graphically the results obtained by the measurement of the velocity of the 

wind and by counting the number of strokes of the pump. These 

diagrams exhibit at a glance the facts which otherwise can be comprehended only by a careful study and analysis of the figures. As the 

wind increases from a gentle breeze the pumps run faster, the number of strokes per mile of wind increasing rapidly up to a certain 

point, but beyond this point the diagrams show that although the 

wind increases in speed, the pump begins to run slower. This apparent eccentricity is due to the simple fact that nearly all mills are so 

constructed that for safety they begin to turn out of the wind when 

it reaches a certain force, and thus decrease their revolutions, until 

in a heavy wind the movement becomes quite slow or may even cease 

altogether, the vanes being as a rule turned edgewise to the direction 

of the air currents.

In these diagrams (figs. 4, 8, 9, 10, 11, 13, 15, 16, 18, and 20) the 

relation between the movement of the wind in miles per hour and the 

number of strokes of the pump is shown by the curved line. The 

space from left to right on these diagrams is proportional to the velocity of the wind, while the distance from the lower line upward is proportional to the number of strokes of the pump. The data expressed 

by these diagrams were obtained directly from the record given by 

the anemometer register. The pen of this connected with the anemometer makes, we will assume, 3 short marks (3 miles) in 15 minutes, 

indicating a mile in 5 minutes, or at a rate of 12 miles an hour. At 

the same time the other pen, connected with the pump and registering each hundred strokes, makes, say, 2 short marks, showing that 

the pump has made 200 strokes for this 3 miles of wind movement, or 

67 strokes in each mile. This fact is entered upon the diagram by 

placing a small circle at a distance from the right corresponding to 12
14 WINDMILLS FOK IRRIGATION. [NO. 8.

miles per hour and a distance from the bottom corresponding to 67 

strokes. In this way each observation is indicated. When these 

points have been plotted, the smooth curve is sketched so as to occupy 

an intermediate position among these. In order to determine the 

number of strokes more accurately than was done by the automatic 

recorder, these were actually counted for a considerable number of 

the observations.

DESCRIPTION OF MILLS TESTED.

Mill No. 1. The tests on this mill were preliminary or experimental 

toward the perfection of the instruments employed, and were not 

completed for discussion.

VELOCITY OP WIND IN MILES PER HOUR. 

15 20 25 30

60

50

40

30

20

10

PIG. 4. Diagram showing results with mill No. 2.

Mill No. 2. This is a 12-foot Woodmanse Mogul, manufactured by 

Woodmanse-Hewitt Manufacturing Company, Freeport, Illinois. 

PI. I shows the mill, tower, pump, and pond, and fig. 2 the working 

parts. The tower is steel, 50 feet high to the axis of the wheel. The 

wind exposure is not good from the north, the mill being 115 feet south 

of a large barn. The wheel has 30 curved fans, each 36 by 13 by 5^ 

inches, set at an angle of 30° with the plane of the wheel. It is back 

geared 3 to 1 and held in the wind by a spring. The pump is Woodmanse make, shown in fig. 3. The cylinder is 9£- inches in diameter; 

the supply pipe is 5f inches in diameter; the length of stroke is 12
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO 8 PL.

VIEW OF MILL NO. 2, WOODMANSE, AND ANEMOMETER.

MUBPHY.] INSTRUMENTS AND METHODS. 15

inches. The well is 3f- by 3f- feet to water, a distance of 14 feet. In 

the bottom of this is put down a 12-inch galvanized iron pipe 20 feet 

into water, forming a small open well. The lift at the time of test 

was 17f feet and the discharge per stroke 144 quarts. The mean 

barometer 'pressure was 26.98 inches, and the mean temperature 94°. 

The cost of mill, tower, pump, and well was about $210. The curve,

PIG. 5. Working parts of aermotor. PIG. 6. Stone pump.

shown in fig. 4, is for a moderately loaded 12-foot mill (536.2 footpounds per stroke), and is seen to start with a wind velocity of about 

11 miles per hour. It ascends very rapidly, reaching a maximum at 

18 miles per hour, and giving 60 strokes per mile. The rest of the 

curve to 30 miles has a gentle slope; the number of strokes per minute, 

from about 5 at 12 miles to about 25 at 30 miles per hour.
16 WINDMILLS FOR IRRIGATION. [NO. 8.

Mill No. S. This is a 12-foot aermotor, manufactured by the Aermotor Company, Chicago, Illinois. PI. II shows the mill with its 

tower, pump, and pond, and fig. 5 the working parts. This mill had 

been in use about a year and all the parts were in good working 

order. The tower is'made of wood, having the axis of the wheel 30 

feet above the ground. The exposure is very good. The wheel has 18 

curved fans, each 44 by 18f by 7f inches, set at an angle of 31° to the 

plane of the wheel. It is back geared 3£ to 1, and is held in the wind 

by a spring. The pump is the Stone make (figs 6 and 7), in which 

the check valve is of the single-flap variety, and the plunger valve 

the double-flap variety. The cylinder is 9^ inches in diameter; the

FIG. 7. Valves of Stone purnp. a, lower valve-seat; 6, ring guide to lower valve; c, lower or 

check valve; d, hook for removing lower valve; e, plunger and valve; /=a, b, and c combined.

supply pipe is 4 inches in diameter, and the discharge pipe is 10 

inches in outside diameter. The length of stroke is 12 inches and the 

discharge per stroke 14^ quarts. The well is 4 by 4 feet and is sunk 

a distance of 8 feet, being down nearly to water. From this to a 

depth of 18 feet it is 3 feet in diameter. In the bottom of this are 

three pipes 12 inches in diameter extending down 5 feet farther. The 

lift at the time of testing was 13f feet. The barometer pressure was 

27.2 inches, and the temperature 85° F. The water is pumped into a 

pond 80 by 75 feet, and a depth of 22 inches can be drawn off. Th^ 

cost of the plant, including mill, tower, pump, and pond, was $145.
U. 8. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 8 PL. II

VIEW OK MILL NO. 3, AERMOTOR.

MURPHY.] INSTRUMENTS AND METHODS. 17

The curve shown in fig. 8 is for a rather lightly loaded mill 415.3 

foot-pounds per stroke. It starts at a velocity of 6 to 7 miles per 

hour, ascends less rapidly than in fig. 4, attains a maximum at about 

15 miles per hour, when the number of strokes per mile is 62, and then 

descends slowly, reaching 50 strokes at 30 miles. The number of 

strokes per minute increases from about 5 at 8 miles to 25 at 30 miles.

Mitt No. 4. This, shown in the foreground of PI. Ill, is an 8-foot 

Ideal windmill, manufactured by the Stover Manufacturing Company, 

Freeport, Illinois. This mill had been in use about one year and all 

the parts were in good condition. The tower is of wood; the axis of 

the wheel is 48 feet above the ground. The wheel has 15 fans, each

10

VELOCITY OF WIND IN MILES PER HOUR. 

15 30

FIG. 8. Diagram showing results with Mill No. 3.

16£ by 7 by 30 inches, set at an angle of 29° with the plane of the 

wheel. It is back geared 2£ to 1 and is held in the wind by a spring. 

The pump is of the Stone make. The discharge pipe is 5f inches in 

diameter and the supply pipe 3 inches in diameter. The length of 

stroke is 8 inches. The plunger and check valves are of the singleflap variety. The well is 2f by 2f feet down, nearly to water, a depth 

of 5% feet. The 3-inch supply pipe extends down to a depth of 14 

feet, and on the end of it is a 3-inch well point 6 feet long. The lift 

may vary from 8^ to 20 feet. It was probably about 12 feet at the 

time of the test. The discharge per stroke was 2 quarts, The mean 

8 2
18 WINDMILLS FOR IRRIGATION.

barometer pressure was 27.19 inches, and the mean temperature 83° F. 

The water is pumped into a pond 115 by 31 feet and 3 feet deep. The 

cost of the plant, including mill, pump, well, and pond, was $80.

The curve shown in Fig. 9, although for a quite lightly loaded 8-foot 

mill 50 foot-pounds per stroke is seen to start in a 10 to 11 mile 

wind. The maximum is reached at 19 miles with a speed of 78 strokes. 

The right portion of the curve is quite steep and is characteristic 

of this make of mill. Mill No. 18 is the same size and make as this 

one, and yet with a load of 89.2 foot-pounds it starts in a 7 to 8 mile 

wind, reaching a maximum at about 13 iniles at a speed of 104 strokes 

pet mile. A second test, when the spring that holds the wind wheel

10

80

VELOCITY OF WIND IN MILES PER HOUR. 

15 20 25 30

70

60

50

12

q 40.

30-

10

FIG. 9. Diagram showing results with Mill No. 4.

in the wind was tightened up somewhat, gave the maximum at a 

velocity of about 15 miles with a pump speed of about 114 strokes. 

The difference in performance appeared to be due to difference in 

pumps and wells.

Mill No. 5. This mill, shown in the background of PI. Ill, is an 

8-foot aermotor, manufactured by the Aermotor Company, Chicago, 

Illinois. The tower is of wood and is 28^ feet high to the axis of the 

wheel. The exposure is good, and all the parts were in good working order at the time of examination, the plant having been in use 

about one year. The wheel has 18 curved fans, each 30 by 12-J by 5£ 

inches, making an angle of 29£° with the plane of the wheel. It is
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 8 PL. Ill

VIEW OF MILL NO. 4, IDEAL, AND NO. 5, AERMOTOR.

MURPHY.] INSTRUMENTS AND METHODS. 19

back geared 3£ to 1. The pump is Stone make. The discharge pipe 

is 6 inches in diameter; the supply pipe, 3 inches in diameter. The 

valves are both of the single-flap variety. The length of stroke is 8 

inches. The well is 4 by 4 feet to water, a depth of 10£ feet. A 12- 

inch wooden curb extends 12 feet farther into the sand and gravel. 

The discharge per stroke was 3£ quarts and the lift 13 feet. The 

water is pumped into a pond 110 by 30 by 2£ feet. The cost of 

plant, including pond, was $80.

This 8-foot mill, with a load of 95 foot-pounds, is shown by fig. 11 

to start with an 8 to 9 mile wind, reaching a maximum at 13 to 15 miles 

with 95 strokes per mile. At 30 miles per hour it is making 77

100

90

80

10

VELOCITY OF WIND IN MILES PER HOUR.

15 30

70

W 

§ 

ID 60

50

40

0<

FIG. 10. Diagram showing results with Mill No. 5.

strokes per mile and 39 per minute. This curve indicates a quite 

heavily loaded mill.

Mill No. 6. This mill, shown in the background of PL II, is an 

8-foot Gem, manufactured by the United States Wind Engine and 

Pump Company, Kansas City, Missouri. The working parts of the 

mill are shown in PL IV. The exposure is good and all the parts are 

in good working order, the mill having been in use only about a year. 

The wheel has 24 curved fans, each 30^ by 10 by 4£ inches, set at an 

angle of 35° with the plane of the wheel. It is back geared 3 to 1. 

The wheel is held in, the wind by means of a weight. The pump is 

Stone make. The discharge pipe is 6 inches in diameter, the supply
20 WINDMILLS FOB IRRIGATION. [NO. a

pipe 4 inches in diameter, and the length of stroke 8 inches. The 

well is open to water for a depth of 6£ feet. The supply pipe is on a 

well point, the end of which is 16 feet below the surface of the ground. 

The lift was 9^ feet and the discharge 3^ quarts per stroke. The 

tower is built of wood and is 24 feet high to the axis of the wheel. 

The mean barometer pressure was 27.02 inches and the mean temperature 85° F. The plunger valve is of the double-flap variety, and 

the check of the single-flap variety.

Mill No. 7. This is a 12-foot aermotor similar to Mill No. 3. The 

tower is steel, having a height of 31 feet to the axis of the wheel. 

The exposure was good and all the parts were in good working order, 

the plant having been in use less than one year. The pump is the 

Stone make, and is like that with Mill No. 3, except that the check 

valve is of the solid-lift variety. The lift was 15^ feet, and the discharge 14^ quarts per stroke. The water is pumped into a pond 135 

by 50 by 2| feet.

10

VELOCITY OF WIND IN MILES PER HOUR.

15 30 35 30

50

g 

0 30

i ' O/O O i 

10

FIG. 11. Diagram showing results with Mill No. 9, aermotor.

Mill No. 8. This is a 10-foot Star wooden mill, manufactured by 

Bradley, Wheeler & Co., Kansas City, Missouri. The tower is made of 

wood and the axis of the wheel is 35^ feet above the ground. The 

water is pumped into an elevated tank 20 feet above the surface of 

the ground, and is used for irrigation. The wheel has 60 plain fans, 

each 37 by 5 by 2f inches, set at an angle of 33° to the plane of wheel. 

It is held in the wind by means of a weight. It is not back geared, a 

stroke of the pump being made to each revolution of the wheel. The 

supply pipe is 2 inches in diameter and terminates in a well point, the 

end of which is 18 feet below the surf ace of the ground. The cylinder
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 8 PL. IV

WORKING PARTS OF MILL NO. 6, GEM.

MTTBPHT.] INSTRUMENTS AND METHODS. 21

is 3 inches in diameter, the discharge pipe li inches in diameter, the 

length of stroke 5 inches. The lift may vary between 28| and 37 feet. 

It was estimated to be about 30 feet at the time of measurement.

FIG. 12. Working parts of Mill No. 10, Ideal.

The discharge per stroke was 0.24 quart. The cylinder leaked some 

at the time of test. After a new cylinder was put in the discharge
22 WINDMILLS FOR IRRIGATION. [NO. 8.

per stroke was increased to 0.40 quart. The mean barometer pressure 

was 27.04 inches; mean temperature, 78° F.

Mill No. 9. This is a 16-foot aermotor. The tower is steel and the 

axis of the wheel is 30 feet above the ground. The wheel has 18 

curved fans, each 59 by 25f by 10£ inches, set at an angle of 30° with 

the plane of the wheel. It is back geared 3£ to 1. The discharge 

pipe is 12 inches in diameter, the supply pipe 6 inches in diameter, 

the cylinder 8 inches in diameter; the stroke, 16 inches. The well is 

4 by 6 feet to a depth of 23 feet, 2 by 2 feet down 8 feet farther, and 

18 inches diameter down 14 feet farther. The water is 39| feet below 

the surface of the ground. The lift is 44£ feet and the discharge 11 

quarts per stroke. The check valve is of the single-flap variety and 

the plunger of the double-flap variety. The mean barometer pressure

60

10

VELOCITY OF WIKD IN MILES PER HOUR.

15 20 25

50

40

30

20

10

FIG. 13. Diagram showing results with Mill No. 11, Ideal.

was 27.04 and the mean temperature 93°. This plant has been in use 

about three years.

The curve, shown in fig. 11, starts with a wind velocity of 8 to 9 

miles and reaches a maximum at 13 miles, with a speed of 53 strokes 

per mile. From this to a velocity of about 19 miles the curve is nearly 

horizontal. From this point it descends slowly to 32 miles, where it 

is making 38 strokes per mile. The piston speed increases from the 

rate of 11 strokes at 12 miles to the rate of 21 strokes at 30 miles per hour.

Mill No. 10. This is an 8-foot Ideal. The tower is made of wood, 

the axis of the wheel being 30 feet above the ground. The wheel has 

15 curved fans, each 31 by 19 by 7 inches, set at an angle of 29^-° with 

the plane of the wheel. It is back geared 2^ to 1. The supply pipe
MURPHY.] INSTRUMENTS AND METHODS. 23

is 1^ inches in diameter, the cylinder 2-J inches in diameter. The 

pump is of the common hand kind, with lift valve of the flap form and 

plunger of the lift variety. The 

valves leak some, as the discharge is greater when the pump 

is working rapidly than when 

it is working slowly. The supply pipe is on a well point 2 feet 

long and 1-J inches in diameter, 

whose lower end is 50 feet below 

the surface of the ground. The 

lift was 33 feet and the discharge 

per stroke one-third of a quart 

when pumping quite rapidly. 

The mean barometer pressure 

was 26.94 inches and the mean 

temperature 97°.

Mill No. 11.- This is a 12-foot 

Ideal, the working parts of which 

are shown in fig. 12. The tower 

is made of steel, the axis of the 

wheel being 30 feet above the 

ground. The exposure is good 

and all the parts are in good 

working order. The wheel has 

21 curved fans, 31 by 19 by 7 

inches, set at an angle of 29i° 

to the plane of the wheel. It is 

back geared 2| to 1, and the 

wheel is held in the wind by a 

spring. The discharge pipe is 

8 inches in diameter and the 

stroke 12 inches. The supply 

pipe consists of two 3-inch pipes 

14 feet long, each terminating 

in a 3-inch well point 3 feet long. 

The valves are both of the singleflap variety. The water is 39^ 

feet below the surface of the 

ground. The lift, as nearly as 

could be ascertained, was 45 feet 

at the time of measurement; the 

discharge, 9 quarts per stroke.

_., . -. . . -, FIG. 14. Working parts of Frizell cylinder. The water is pumped into a pond

60 by 40 by 6 feet. This plant has been in use about three years. 

The mean barometer pressure was 26.91 inches, and the mean temperature 91° F.
24 WINDMILLS FOR IRRIGATION. [NO. 8.

This curve, shown in fig. 13, is for a heavily loaded (843.7 footpounds per stroke) 12-foot mill. It starts with a velocity of about 10 

miles per hour and reaches a maximum at about 23 miles, with a 

piston speed of 57 strokes per mile. At 30 miles it is making 51 

strokes per mile. The maximum point of this curve is much farther 

to the right than that of any other curve. The number of strokes per 

minute increases from 5 at 12 miles to 25 at 30 miles.

Mill No. 12. This is a 14-foot Ideal, shown in fig. 16. The tower 

is made of steel, 30 feet high to the axis of the wheel. The wheel 

has 24 curved fans, each 48f by 17-J by 8 inches, set at an angle of 30° 

with the plane of the wheel. It is back geared 2-J to 1. The pump 

is Frizell make, shown in fig. 14. The discharge pipe is 10 inches in 

diameter; the cylinder 9^ inches; the supply pipe is 6 inches in diam60

10

VELOCITY OF WIND IN MILES PER HOUR. 

15 20 25

50

40

£ fe0 30

20

10

FIG. 15. Diagram showing results with Mill No. 12.

eter, terminating in a well point 10 feet long and 6 inches in diameter, the lower end of which is 32 feet below the surface of the ground. 

The lift, as nearly as could be estimated, was 11 feet; the discharge, 

11.6 quarts per stroke. The mean barometer pressure was 27.04 

inches and the mean temperature 81° F. The water is pumped into 

a reservoir 100 by 100 feet and 3 feet deep. The pump has been in 

use about one year.

The curve, shown in fig. 15, is for a very lightly loaded (263.5 footpounds) 14-foot mill. This load is only 31 per cent of that of the 12- 

foot mill, No. 11. The curve starts with a 7 to 8 mile wind and reaches 

a maximum at 15 miles with a piston speed of 58 strokes per mile of 

wind. At 30 the piston speed is 47 strokes.
U. S. GEOLOGICAL SURVEY

WATER-SUPPLY PAPER NO. 8 PL. V

VIEW OF MILL NO. 12, IDEAL.

MURPHY.] INSTRUMENTS AND METHODS. 25

Mill No. IS. This is a 12-foot aermotor, shown in PL VI. The 

tower is made of wood, with the axis of the wheel 25 feet above the 

ground. The exposure is good and the plant in excellent condition, 

having been in use about one year. The wheel is the same as in mill 

No. 3. The pump is Stone make; the discharge pipe is 10 inches in 

diameter; the supply pipe is 5 inches in diameter on a well point 10 

feet long, the lower end of which is 17 feet below the surface of the 

ground. The length of stroke is 12 inches. The plunger valve is of 

the double-flap type and the check valve of the single-flap variety. 

The discharge per stroke at the time of the test was 14.4 quarts and 

the lift about 11 feet. The mean barometer pressure was 27.09 inches 

and the mean temperature was 91° F. The. important difference

60

50

10

VELOCITY OF WIND IN MILES PER HOUR.

15 20 25

30

20

10

 8-°-

PIG. 16. Diagram of results with Mill No. 19.

between this plant and No. 3 is that the latter has a 4-inch supply 

pipe and an open well, while the former has a 5-inch supply pipe on a 

well point.

Mill No. 14. This is a 12-foot Gem, like the one shown in PL IV, 

on a 60-foot steel tower. The pump is Gause make; the cylinder is 8 

inches in diameter; the length of stroke 9 inches. The supply pipe 

is a 12-inch open well. The discharge per stroke was 9f quarts and 

the lift 15^ feet. The wind velocity was not measured for this mill.

Mill No. IS. This is a 10-foot Gem, similar to that shown in PL IV. 

The tower is made of wood, the axis of the wheel being 34 feet above 

the ground. The mill is in good working order, but the exposure is 

not good on account of trees. The wheel has 24 fans, each 36 by 11 

by 4f inches, set at an angle of 35° with the plane of the wheel. It is
26 WINDMILLS FOR IRRIGATION. [NO. 8.

back geared 3 to 1. The pump is Stone make; the discharge pipe is 8 

inches in diameter, the supply pipe 3 inches in diameter, the stroke 8 

inches. The supply pipe is on a 3-inch well point 8 feet long, whose 

lower end is 21^ feet below the surface of the ground. The plunger 

valve is of the single-flap form and has a check lift. Depth of water 

is 10 feet. The discharge per stroke is 7 quarts; the lift, about 15 

feet; the mean barometer pressure was 27.05 inches and the mean 

temperature was 84° F.

Mill No. 16. This is a 10-foot Halliday, pumping water into the 

same pond as No. 15. It is similar to the mill shown in fig. 12. The 

tower is wood, and the axis of the wheel 28 feet above ground. The 

wheel has 78 fans, each 36^ by 4 by 2^ inches, set at an angle of 35^° 

to the plane of the wheel. It is not back geared. The pump is Gause

FIG. 17. View of Mill No. 20, Jumbo.

make, with a discharge pipe 6 inches in diameter; the supply pipe is 

4 inches in diameter. There is a 6-inch galvanized iron pipe forming 

an open well extending 15 feet into the water. The depth to water is 

11 feet, the lift is 16 feet, and the discharge per stroke is 3 quarts. 

The mean barometer pressure was 27.02 inches, and the mean temperature 94° F.

MiU No. 17. This is a 12-foot improved Gem on a 30-foot steel 

tower. The wheel has 32 curved fans, each 42 by 11^ by 4f inches, 

set at an angle of 37° with the plane of the wheel. It is back geared 

2 to 1. The pump is Gause patent, with an 8-inch discharge pipe, 

4-inch supply pipe, 12-inch stroke, and an open well formed of a 12- 

inch wooden casing. The depth to water is 17£ feet, the lift 21f feet,
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 8 PL. VI

VIEW OF MILL NO. 13, AERMOTOR.

MURPHT.] INSTRUMENTS AND METHODS. 27

and the discharge per stroke 8f quarts. The mean barometer pressure 

was 27.05 inches, and the mean temperature 93° F. This mill, although 

nearly new, does not work well. It is out of plumb. Only a few 

measurements of the number of strokes per mile of wind were made. 

Mill No. 18. This is an 8-foot Ideal on a 36-foot wooden tower. 

The exposure was good, and the parts were in good working order. 

The wheel is like that of Mill No. 4. The pump is Stone make, with a 

6-inch discharge pipe. There is no supply pipe, the cylinder being under 

water, with 3^ inches opening to it from below. The valves are lift 

variety for check, and single flap for plunger. The well is open, 

formed by a 10-inch galvanized pipe in the bottom of a part 4^ feet 

in diameter and 8 feet deep. It is 11 feet to water. The lift is 14f 

feet, and the discharge per stroke 2.92 quarts. The mean barometer 

pressure was 27.01 inches, and the mean temperature 83° F. The 

cost of the plant, including pond, was 1125.

VELOCITY OF WIND IN MILES PER HOUR.

50

40

30

a 

o 20

10

FIG. 18. Diagram showing results with Mill No. 20.

Mill No. 19. This is a 12-foot Gem, shown in PL VII, on a 30-foot 

wooden tower. The exposure is good, and the mill is in good working order. The wheel is like that of Mill No. 17. The pump is Stone 

make, with 10-inch discharge pipe and a 4-inch supply pipe. The 

length of stroke is 10 inches. The supply pipe is on a 4-iiich well 

point 9 feet long, the end of which is 23 feet below the surface of the 

ground. The check valve is of the lift type, and the plunger is of 

the single-flap type. The lift was about 18 feet, and the discharge 

per stroke 12 quarts. The mean barometer pressure was 27.13 inches, 

and the mean temperature was 70° F. The water is pumped into a 

reservoir 120 feet by 60 feet.

The curve, seen in fig. 16, shows that a 9-mile wind is necessary to 

start this mill, and that the greatest number of strokes per mile of
28 WINDMILLS FOR IRRIGATION.

wind is 45, about 25 per cent less than most 12-foot steel back-geared 

mills. The piston speed is less than for other 12-foot mills, being at 

the rate of 6 at 12 miles and at the rate of 16 at 25 miles per hour. 

Mill No. 20. This is a 15^-foot Jumbo, shown in fig. 17. Its axis

A, bed plate; B, turntable; 

S, main shaft; C, front plate; 

D, sliding head; E, tie rod; 

V, vane; F, fans or sails; M, 

crank plate; G, truss frame; 

H, truss rod; L, pitman; L, 

fan lever; M' M', masts; P, 

weight lever; E, shut-off rod; 

S, sleeve; W, weight; W", 

counter-weight; X, swivel 

box; Y, spider; Z, sliding box.

1- iu. id. Working parts of Halliday mill.

is a steel shaft 8 feet above the ground. It has 6 fans, each 9^ by 3% 

feet; the outer radius is 7f feet and the inner 4£ feet. This mill 

operates two pumps, one at each end of the axis, each having a 6-inch
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 8 PL. VII

VIEW OF MILL NO. 19, GEM.

MtTRPHY.] INSTRUMENTS AND METHODS. 29

cylinder, a 3-inch discharge pipe, and a 3-inch supply pipe on a well 

point 5 feet long. The discharge of the two pumps was 10 quarts per 

stroke ;*the lift was about 14 feet. The mean barometer pressure 

was 27.09 inches and the mean temperature was 85°. The anemometer was held 144 feet above the surface of the ground, or at the elevation of the center of a fan when in its highest position. The wheel 

is set in a large box extending up to a level with the axis of the 

wheel to prevent the wind from striking the part of the wheel below 

its axis.

The curve, shown in fig. 18, is seen to be different from the others 

in that it has no maximum. It starts with a velocity of 13 to 14 

miles, and beyond 20 miles it appears to be nearly a straight line.

130

100

10 25

60

40

20

FIG. 20. Diagram of results with Mill No. 21.

Mill No. 21. This is a 12-foot Halliday, shown in PL VIII, on a 31- 

foot wooden tower. It was made by the United States Wind Engine 

and Pump Company, of Batavia, Illinois. The working parts are 

shown in fig. 19. The wheel has 64 fans, each 42^ by 5 by 2f inches, set 

at an angle of 35° with the plane of the wheel. It is not back geared, 

and regulates itself on the centrifugal principle by the fans taking 

the direction of the wind. The pump is Stone make, with 7^-inch 

discharge, 4-inch supply pipe, and 7-inch stroke. The check valve is 

lift form and the plunger double flap. The well is open, formed by 

a wooden curb 12 inches in diameter sunk in the bottom of a dug 

well 9 feet deep. The depth to water was 11^ feet and the lift 15 

feet. The discharge per stroke was 4^ quarts when pumping quite
30 WINDMILLS FOR IRRIGATION. [NO. 8.

rapidly (30 strokes per minute). The valves were not in very good 

repair, and the pump lost its priming after a time.

This curve, shown in fig. 20, for a lightly loaded (141.5 footpounds), direct stroke 12-foot mill, is seen to start with a velocity of 

9 to 10 miles, and to reach a maximum at 19 miles, with a piston speed 

of 112 strokes per mile. At 30 miles the number of strokes is about 

98 per mile. The number of strokes per minute varies from 14 at 12 

miles to 45 at 25 miles.

FIG. 21. Working parts of Power Mill No. 26.

Nos. 22 to 24. The results obtained from these mills were not 

sufficiently complete for discussion.

Mill No. 25. This is an 8-foot steel mill, on a 32-foot steel tower, 

made by Fairbanks, Morse & Co. The wheel has 18 curved fans, each 

29 by llf by 5% inches, set at an angle of 29° with the plane of the 

wheel. It is back geared 2^ to 1. The pump is of the common hand 

variety, with 2^-inch cylinder, 1^-inch supply and discharge pipes,
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 8 PL. VIII

VIEW OF MILL NO. 21, HALLIDAY.

MURPHY.] INSTRUMENTS AND METHODS. 31

and 4-inch stroke. The well is open 6^ feet to water. The discharge 

per stroke was 0.31 quart, and the lift 8^ feet. The water raised is 

used for watering stock.

Mill No. 26. This is a 14-foot steel power mill, on a 40-foot steel 

tower, made by the Perkins Windmill Company, Mishawaka, Indiana.

FIG. 22. Working parts of Power Mill No. 27.

The working parts are shown in fig. 21. The wheel has 32 curved 

fans, each 41 by 14^ by 7f inches, set at an angle of 31° with the 

plane of the wheel. The shaft is geared forward 6 to 1; that is, the 

shaft makes 6 revolutions to each revolution of the wind wheel. The 

power was measured by the use of a Prony friction brake. The radius 

of the brake pulley was 5 inches, and the length of the brake arm
32 WINDMILLS FOR IRRIGATION. [NO. 8.

inches. The number of revolutions of the brake pulley per mile of 

wind was found from a speed counter. This mill was tested twice. 

Between the dates of testing, some repairs were made to the shafting, 

causing the cogwheels to bind less tightly. The figures given in 

Table I for this mill are those obtained from the second test, and are 

much larger than those from the first test. The load was 6 pounds on 

the arm 33^ inches long. The mill has been in use about one year.

Mill No. 27. This is a 12-foot power aermotor on a 30-foot steel 

tower. The wheel is the same as in mill No. 3. The horizontal shaft

is geared forward 6 to 1. Fig. 22 

shows the working parts of the mill 

and fig. 23 the foot gear. A 9^- 

inch brake pulley was clamped to 

the horizontal shaft at a, fig. 23. 

The power was measured by a 

Prony friction brake on this 9-Jinch pulley, the arm of the brake 

being 35^ inches in length. The 

number of revolutions per mile 

of wind was found from a speed 

counter. The mean barometer pressure on October 10, 1896, when

FIG. 23. Foot gear of power mill No. 27. ., _ , quite a number or measurements of

power were made, was 28.9 inches, and the mean temperature was 

46° F. These have been taken as a standard, and measurements 

made on other days reduced to what they would have been had the 

pressure been at the standard.

DISCUSSION OF THE RESULTS.

The following table gives in condensed form the results obtained 

from the observations upon the windmills described in the preceding 

pages. This table shows, first, the arbitrary number given to the 

mill; next, the name of the mill and that of the owner of the particular one tested. Following this is the diameter of the wind wheel in 

feet. After this are four general divisions within which the observations have been classified according to the average velocity of the 

wind in miles per hour, beginning with a wind movement of 8 miles 

per hour and ending with one of 30 miles per hour. The number of 

strokes per mile of wind was obtained, as before stated, directly from 

the record given by the anemometer register. The second set of 

figures, that giving the number of strokes per minute, is obtained by 

simple division from the first set, the number of strokes per mile 

being divided by the number of minutes required for the wind to 

make a mile. The next set of figures gives the number of gallons per 

hour that each pump was lifting under the different wind velocities. 

This is found from the preceding set by multiplying the number of 

strokes per minute by sixty (number of minutes in an hour), and this 

by the number of gallons raised at each stroke,
MURPHY.] DISCUSSION OF RESULTS. 33

The next set of figures, that giving the useful work in horsepower 

for the different velocities, is found from the preceding set by multiplying each of these by the factors which convert the number of 

gallons or the quantity of water raised through the given height 

into the corresponding horsepower. One horsepower is the rate of 

work when 33,000 pounds is raised to a height of 1 foot in one 

minute, or, in other words, is 33,000 foot-pounds. Thus to obtain the 

useful work in horsepower it is necessary to multiply the number of 

gallons by the weight in pounds of each gallon and by the height in 

feet to which this is raised, and to divide this by 33,000. This is expressed mathematically by the simple formula: Horsepower = ->Q n^ *

where n is the number of strokes per minute, q the number of gallons 

per stroke, g the weight in pounds per gallon, and Ti the lift in feet.

FIG. 24. View of Defender mill and elevator.

The latter part of the table gives, after useful work in horsepower, 

the foot-pounds of useful work per stroke of the pump, this being 

obtained in the manner indicated above by multiplying the amount of 

water in pounds raised each stroke into the height in feet. Next to 

this is the total vane area of the mill in square feet, this being obtained 

by a careful measurement of the size of the vanes. Next .to this is 

appended the total lift in feet, obtained as noted under the descriptions of the mills, and also the size of the pump (inside diameter of 

the cylinder) and the length of stroke, both of these being given in 

inches.

IKK 8 3
34 ' WINDMILLS FOR IRRIGATION.

Results of measurements and computations of pumping mills.

[NO. 8.

Mill No.

2 

a

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

15 

16 

17

18

19 

20 

21 

25

6 

fc

I

2 

3 

4 

5 

6 

7 8- 

9 

10 

11 

12 

13 

15 

16 

17

18

19 

20 

21 

25

Name.

Wooc 

Aerir 

Ideal 

Aerrt 

Gem 

Aerrt 

Star 

Aerrt 

Ideal 

d

Lmanse. 

lotor .__

lotor . . .

lotor - _ _

lotor . . _

o

.....do

Aerrt 

Gem 

Halli 

Gem

Ideal

Gem 

Juml 

Halli 

Fairt

lotor . . .

anks 

Owner.

I. L. Diesem . 

T. D. Carless. 

E. S. Austin _ 

EllaHorner__

O. V. Folsom. 

J. C. Kitchen. 

F. M. Dunn._ 

_____do---- 

Wm. Coulters 

Jas. Alien . 

 doD. B. Menke . 

Fred. Pile. 

W. E. Trell..

W.T.Cowhick 

J.E. Hunt 

Wm. Brown .

o3

tsl 

02

Ft. 

12

12

8 

8

8

12 

10 

16 

8 

12

14 

13 

10 

10 

12

8 

12

15J

1?

8

Number of strokes per 

mile of wind when 

velocity per hour in 

miles is 

8

"16

"216 "ioe

..

-

23

30 

60

92

Number gallons pumped per hour 

when wind velocity per hour in 

miles is 

8

i, 153

101

70

535

'"iso

348

~"~~57

12

1,131 

2,610 

306 

977 

725 

2,445 

108 

1,749 

125 

648 

1,880 

2,376 

819 

1,017 

765

879 

1,116

945 

136

16

3,480 

3,567 

579 

1,318 

1,047 

3,387

2,326 

167 

1,714

2, 708 

3,694 

1,250 

1,526 

1,632

1,135 

2,142

795

1,924 

173

20

4,415 

4,306 

759 

1,564

1,287 

4,075

2,838

~2,~538 

3,312 

4,536 

1,543 

1 922 

2,206

1,218

2,646

1,605

2,518 

177

25

5,069 

5,014 

843 

1,817

1,486 

4,740

3,234

"sVlSO 

3,709 

5,314 

1,633 

2,362

1,196

2,880

2,625

3,010 

155

30

5,503 

5,437 

750 

2,021 

1,667 

5,041

3,465 

~3,~375 

~5,~940

......

------

12

2f 

6( 

K 

9T 

65 5' 

15( 

5; 

12t 

2A 

5, 

5; 

31 11;

3( 

101 

31

7 

14(

16

> 60 

) 62 

' 73 

J 94 

I 67 

59 

). 

5 53 

> 125 

t 48 

> 59 

) 64 

) 45 

J 127 

) 48 

fa 114 

\ 98 

L 45 

20 

) 107 

> 140

20

61 

6( 

7( 

9( 

6 

5

5!

5 

5J 

6, 4^ 

12! 

5! m

&

4

a 11; 

n<

25

L 56 

) 56 

i 68 

1 83 

3 61

r 53

30

51

50 

50

n

47

2 47| 42

' 56 

1 53 

5 59 

t 35 

i 126 

3

I 79 

t 66 

I 3g 

I 42 

2i 107 

tl 80

50 

"55

}-

Number of strokes per minute when velocity per hour 

in miles is 

8

~~5"3

~?8~0

"ii'i 

"3" I

4.0

8.0

12.3

Useful work in horsepower 

when wind velocity per 

hour in miles is 

8

. D67

mi "."616

~.~025

.012

.022

12

.085 

.151 

.015 

.053 

.029 

.160 

014

.325 

.017 

.123 

.087 

.110 

053

.067 

070

.054

085

OfiO

.002 .005

16

.260 

.207 

.029 

.072 

.042 

.221

.433 

.023 

.325 

.125 

.171 

.082

.103 

c.149

(082) 

.070 

.162

.047

1 n

.007

20

322 

250 

038 

086 

051 

266

448 

032 

481 

153 

210 

101

130

202

SPm

095

159

008

25

.379 

.291 

.043 

.099 

.059 

.309

.601 ."eoo"

.172

.247 

099

.159

.(S?

?19

154

184

005

30

.411 

.315

.038 in

.065 

.329

644

"."639 

"."275

.....

- 

.....

12

5.2 

12.0 

10.2 

18.6 

12.4 

11.4 

30 0

10.6 

25.0 

4.8 

10.9 

11.0 

7.8 

22.6 

6 0

20.2 

6.2

140

29.2

16

16.0 

16.4 

19.3 

25.1 

17.9 

15.8

14.1 

33.3 

12.7 

15.7 

17.1 

11.9 

33.9 

V/, 8

26.1

11.9 

5 3

28,5

37.3

Foot-pounds use- ful work per of stroke pump.

536.2 

415.3 

50.0 

94.9 

77.6 

461.9 

15.0 

1,013.3 

22.8 

843.7 

263.5 

330.0 

219.0 

100.0 

385.0

89.2

450.0 

291.2 

141.5 

5.5

20

20.3 

19.8 

25.3

29.8 

22.0 

19.0

17.2

18.8 

19.2 

21.0 

14.7 

42.7 

17 3

28.0

14.7 

10 7

37 S

38.0

a 1-4

c3 QJ

£2 

"8

a> c8 agC3 to

>

69.4 

72.9 

36.1 

33.7 

36.9 

72.8 

59.8 

133.6 

42.0 

75.3 

103.6 

72.8 

47.3 

61.3 

75.8

42.0

77.6 

73.6 

69.7 

30.2

25

23.3 

23.1

28.1 

34.6 

25.4 

22.1

19.6

23.3 

21.5

24.6 

14.6 

52.5

27.5 

16.0

17 fi

44 6

33.3

+i

0 

0 <"H

4^"

CM

3

17.75 

13.75

13.00 

13.00 

9.60 

15.50 

30.00 

44.25 

33.00 

45.00 

11.00 

11.00 

15.00 

16.00 

21.75

14.75

18.00 

14.00 

15.00 

8.50

30

25.3 

25.0 

25.0

38.5 

28.5 

23.5

21.0

25.0 

"27."5~

::::::

......

rO 

ft 

S 

& 

ft

"g

0} 

tsl

53

9£xl2 

9jxl2 

5fx8 

6 x8 

6|x8 

9Jxl2 

3 x5 

8x16 

2Jx6 

7fxl2 

9Jxl2 

10 x!2 

8 x8 

6 x8 

8x12

5ix8

10 xlO 

6 x!2

7|x7 

21x4

a Two pumps, each 6 by 12 inches.

6 Inside diameter of cylinder by length of stroke.

c Test after increasing the tension of spring which holds wind wheel in the wind.

It is seen that mills of the-same size differ very much in the useful 

work they do, and that some of the large mills are doing very little 

more work than some of the smaller ones. Nos. 4 and 18 are the 

same size and make; the wells, however, are very different; the latter 

is doing two or three times more work than the former. The 12-foot 

mill, No. 11, is doing nearly as much useful work as the 16-foot mill, 

No. 9, and three or four times more useful work than the 14-foot mill,
MURPHY.] DISCUSSION OF RESULTS. 35

No. 12, while it is doing 300 per cent more work than No. 21. The 

15^-foot Jumbo will probably do very little more work during the season than a good 8-foot mill.

RELATION BETWEEN WIND VELOCITY AND STROKES.

The preceding diagrams show graphically the relation between the 

wind velocity in miles per hour and the strokes of the pump. The 

curves, as will be noted, differ considerably; but with the exception 

of No. 23 for Mill No. 20, they agree in that they rise rapidly, 

reaching the highest point or greatest number of strokes at from 13 

to 19 miles of wind velocity. From this point they descend slowly. 

They differ much in the position of the beginning of the curve, or the 

velocity required to start the mill. Some will run in an 8-mile wind; 

others require a 10 or 12 mile wind to start them. Some rise less rapidly than others; a notable case is Mill No. 11. Some descend much 

more rapidly than others after reaching the highest point. This is 

especially true of the 8-foot Ideals. Mill No. 12 (PI. V) required a 

14-mile wind to start it, and does not appear to have a maximum.

The shape of the curve, especially the position of its beginning 

point, is due to the load on the pump, or the number of foot-pounds 

per stroke. Increasing the load moves the curve to the right and 

raises it higher. This will be shown more fully in the discussion of 

power Mill No. 27. The height.of the highest point and its position 

depend on the tension of the spring, or the weight which holds the 

mill in the wind. The greater the tension, the higher the summit and 

the farther it is to the right. Mill No. 20 has no method of reducing 

the wind area, and hence the curve has no summit, as shown in fig. 

17. The less the tension in the spring, the steeper the descent from 

the highest point. The gearing that is, the mechanism for causing 

the pump to make a stroke to each revolution of the wheel, or only a 

stroke every second or third revolution modifies the curve. If working with a direct stroke, the curve is much higher and is farther to 

the right than if back geared, as shown by a comparison of mills 3 

and 21, shown in figs. 8 and 20.

USEFUL WORK IN HORSEPOWER.

The relation between wind velocity and horsepower is shown graphically for five 12-foot mills on djagram No. 31 and for four 8-foot mills 

on- diagram No. 32. Examining the five curves of fig. 25, we see that 

No. 11, the one which gives the greatest horsepower, has the heaviest 

load and requires the greatest wind velocity to start it. No. 2 has 

about five-eighths the load of No. 11, does less work, and requires 

about the same wind velocity to start the pump. No. 3 has a lighter 

load than No. 2 and will start in a wind of about 7 miles per hour. 

No. 19 has a little heavier load than No. 3 and does much less work
36 WINDMILLS FOR IRRIGATION.

at all velocities. The latter requires a 9 to 10 mile wind to start it, 

while the former will start in a 7 to 8 mile wind. No. 21 is doing the 

least work of the five, and requires about an 11-mile wind to start it. 

It is a wooden mill working direct stroke, while the others are steel 

mills and back geared. It must be understood in this comparison 

that no correction or allowance is made for difference in temperature 

and barometric pressure, nor for the fact that in Nos. 11 and 19 the 

pumps are in well points, while in the others they are in open wells. 

It is seen that in fig. 25 none of these curves reach a maximum

10

VELOCITY OF WIND IN MILKS PER HOUR.

15 30 35

PIG. 35. Diagram showing relation between horsepower and wind velocity for five 13-foot mills.

point below 30 miles per hour. They do, however, for some higher 

velocities, since the work per stroke of pump is nearly constant for 

each pump for all velocities, though not the same for one pump as 

for another. These curves also give the relation between wind velocity and number of strokes of pump per minute.

In fig. 26 the curve for No. 18 is seen to reach a maximum at 20 

miles per hour, and No. 4 reaches a maximum at about 25 miles per 

hour. The others reach their maximum points for velocities at about 

30 miles. These maximum points are points of greatest piston speed, 

and are produced by a reduction of wind area, the wind wheel turning 

out of the wind. This make of mill is seen to '' govern " or turn out of 

the wind at a lower velocity than other makes. Comparing the curves 

on diagram No. 26, we see that the one doing the most work in high 

velocities is No. 5, the one which is the most heavily loaded. The
MURPHY.] DISCUSSION OF RESULTS. 37

principal differences between Nos. 4 and 18 the ones giving the most 

and the least work for velocities less than 22 miles per hour are in 

the load and well. No. 4 has five-ninths of the load of No. 18, and 

is on a well point. The two doing the least work are on well points. 

Mill No. 25 is used to pump water for stock. Comparing it with 

that of, say, No. 5, we see that its load is about five-ninths, and that 

it is doing about one-tenth as much work as the latter. It will start 

with a wind velocity of about 6 miles per hour, while the latter 

requires a velocity of about 8£ miles.

10

VELOCITY OF WIND IN MILES PER HOUR. 

15 20 35 30

.10

.08

0.06

.04

.03

FIG. 36. Diagram showing relation between horsepower and wind velocity for four 8-foot mills. 

COMPAEISON OF BACK-GEARED AND DIRECT-STROKE MILLS.

Comparing the curves of fig. 25, which gives the relation between 

horsepower and wind velocity for five makes of 12-foot mills, we see 

that the one giving the least power is working direct stroke. It 

required the greatest velocity to start it, and is doing less work at all 

velocities than any of the other four. In a 20-mile wind it is making 

40 strokes per minute, and in a 25-mile wind 48 strokes per minute. 

This is too rapid a rate; 30 strokes per minute is as rapid as a pump 

of this size should work. Hence the horsepower of this mill would be 

less than shown in the diagram if run at a proper rate. The only way 

that it can be made to do more work without back gearing it is by 

increasing the load per stroke, but this will increase the velocity 

necessary to start it, and cause it to remain idle a greater part of 

the time. Comparing the working of this mill and, say, No. 3, we see 

that the work per stroke of No. 3 is 415 foot-pounds and that of No. 

21 is 141 foot-pounds, or the former is doing about three times as much
38 WINDMILLS FOE IBEIGATION.

work per stroke as the latter, and the latter is making about 1.8 times 

as many strokes per minute as the former in a wind velocity of 16 or 

more miles per hour. The former being back geared 3£ to 1, its wheel 

is revolving about 1.9 times faster than that of the latter. Now, 

examining the curves of fig. 27, we see that the speed of the wheel 

has much to do with the useful work done. When the speed is low, 

as it must be in a mill working direct stroke and not too rapidly for 

proper action of the valves of the pump, a slight increase in load 

reduces the speed a good deal. When the speed is nearly doubled, 

as in the case of Mill No. 3, the load may be increased considerably 

without reducing the speed much. Hence back gearing not only 

enables the mill to work with a given load in a much less wind velocity 

than one working direct stroke with the same load, but it enables the 

wheel to run at a velocity that gives more power.

PUMP LOAD DUE TO WELL POINT.

On examining well points that have been used for a time, it is seen 

that many of the little openings through which the water passes into 

the pump have become filled with fine grains of sand, thus reducing 

the area through which the water can enter the pump. If this area 

was of the proper amount when the point was new, it has become too 

small after having been used for a time, or after standing in the 

ground for a time without being used. If this area is too small to 

allow free flow into the pump, an added load is put on the pump.

To measure the mean pull of the pump, an instrument was devised 

by Mr. R. G. Stone, of Garden, consisting essentially of a spiral 

spring, whose compression was proportioned to the pull, and a pencil 

which moved up and down over a smooth surface. The spring was 

calibrated and the pull in the pump rods of four pumps measured 

with it. The four pumps selected were operated by the same size and 

make of mill, and the pumps were the same except as to size of supply 

pipe, valves, and kind of well. The discharge was practically the 

same, but the lifts differed slightly. These were Nos. 3, 7, 13, and 

22. The following table gives the pull in each case after reducing to 

a common lift of 17 feet:

Added load due to pump.

No. mill.

3......

7......

13......

22......

Lift.

134

17

12

13*

Kind of well.

Open ..--.-..-.---

4-inch well point . .

Mean pull.

Pounds. 

597

734

944

819

The straining capacity of No. 7 is not as great as that of No. 3, and 

the resistance of the valves is greater in No. 7 than in No. 3.
MURPHY.] DISCUSSION OP RESULTS. 39

USEFUL WORK DONE IN A GIVEN TIME.

The useful work which two mills of the same wind area, exposure, 

and general character will do depends on the magnitude of the load 

on the mill and the wind velocity. If the mill is heavily loaded it 

will do more work in velocities of 12 or more miles per hour, and less 

in lower velocities than one of a lighter load. The useful work done 

in a given time is the product of the work done per hour at the mean 

velocity, and the number of hours during that time. If the mean 

velocity at a given place is low, the mill load must be less for maximum work than that at a place where the mean velocity is higher. 

To illustrate this fact we use the results of tests of two 12-foot pumping mills (fig. 25): No. 11, heavily loaded, and giving the greatest 

horsepower of all the mills tested at high wind velocities; and No. 3, 

giving the greatest power at low velocities. The useful work per 

stroke of pump is 844 foot-pounds for No. 11, and 415 foot-pounds 

for No. 3. The useless work of the former is greater than that of the 

latter, since the pump is on two well points in the former, while the 

pump of the latter is in an open well.

The relation between the horsepower and the wind velocity for 

these mills is shown in the diagram (fig. 25). The curves are seen to 

cross each other at a wind velocity of 12^ miles per hour. For less 

velocities than this No. 3 is doing more work per hour than No. 11, 

and for greater velocities No. 11 is doing more work than No. 3. If 

the velocity at this place were, say, not more than 13 miles per hour, 

it is very evident that mill No. 3 would do more work in any time than 

No. 11.

There is no record of wind movement at Garden, Kansas, for any 

considerable length of time. There is one, however, for Dodge, 50 

miles east of Garden, kept by the United States Weather Bureau, 

which may be used for this purpose. The following table gives the 

mean number of hours per month for the six months, April to September, for the seven years 1889 to 1895, that the wind movement was 

0-5, 6-10,11-15,. 16-20, 21-25, 26-30, 31 and upward miles per hour.

Mean wind movement at Dodge, Kansas, for the seven years 1889 to 1895.

Months.

April __--.

May ......

June ......

July......

Aiigust -..

September

Mean _

0-3

116

116

120

144

178

* 166

140

6-10

175

195

187

218

230

182

198

11-15

157

168

139

176

152

152

157

16-2O

113

120

111

117

99

93

109

21-25

76

74

86

57

62

75

72

36-30

43

39

49

S3

18

34

34

31 and

upward.

40

32

28

9

5

18 '

22
40 WINDMILLS FOR IRRIGATION. [NO. 8.

It is seen from this table that the wind velocity is 5 miles or less per 

hour for 140 hours per month at this place. During this time neither 

of these mills will do any work, as neither will start in a 5-mile wind. 

The velocity is from 6 to 10 miles per hour for 198 hours per month. 

Mill No. 3 will start in about a 7-mile wind, and hence will run about 

four-fifths of this time, or 158 hours. No. 11 requires Hi miles of 

wind to start it, and will do no work during this time. The velocity 

is 11 to 15 miles per hour for 157 hours during the month. No. 3 will 

work all of this time, and No. 11 about nine-tenths thereof, or 141 

hours. Both mills are running for all higher velocities. Mill No. 3 

will run (if in the wind) about 75 per cent of the time at this place, and 

No. 11 about 51 per cent of the time.

Comparative performance of two mills.

Velocities.

6-10... ........

11-15...........

16-20...........

21-25...........

26-30...........

31 and upward . 

Sum....... ...

Mill No. 3.

Hours.

158 

157 

109 

72 

34 

22

Power.

0.067 

.168 

.230

.277 

.308 

.320

Product.

10.6 

26.4 

25.1 

19.9 

10.5 

7.0

99.5

Mill No. 11.

Hours.

0 

141 

109 

72 

34 

22

Power.

0.0 

.19 

.40 

.56 

.63 

.64

Product.

0.0 

36.8 

43.6 

40.3 

21.4 

14.1

146.2

Columns 2 and 5 of the above table give the number of hours during 

the mean month that each mill was running with a wind velocity of 

from 6 to 10, etc., miles per hour. Columns 3 and 6 give the horse-- 

power for the mean velocity; for example, 0.168 is the horsepower 

for No. 3 at 13 miles per hour, and 0.19 is the horsepower for No. 11 

for the same velocity. Columns 4 and 7 give the product of the number of hours and horsepower that each mill is yielding during the 

month. It is seen that No. 11 is doing 31 per cent more useful work 

than No. 3. If this comparison is made for the month of August, it 

will be found that No. 11 will do 26 per cent more useful work during 

this month than No. 3.

POWER MILLS.

The working parts of Power Mill No. 27 are shown in fig. 22. Instead 

of the reciprocating motion of the pumping mill, there is here a central shaft which is caused to rotate by beveled cog wheels. The sizes 

of the cog wheels are so taken that this central shaft makes six revolutions to one of the wind wheel. The pumping mill being back 

geared 3^ to 1, and the power mill being geared forward 6 to 1, the 

vertical shaft makes twenty revolutions to one stroke of a pump
MURPHY.] DISCUSSION OF RESULTS. 41

worked by a pumping mill whose wind wheel is running at the same 

rate as that of a power mill. At the lower end of this shaft is a foot 

gear, shown in fig. 23, on which is placed the pulley which runs the 

grinder or other machine.

The power that a windmill is capable of developing can be determined better from a power than from a pumping mill, because the 

efficiency of the pump, which may be anything from 20 per cent to 85 

per cent, is eliminated, and because the load on the mill can be varied 

at will, and thus the effect of load on the power can be determined 

for different wind velocities. To measure the power of this mill a 

pulley 9^ inches in diameter was fitted to the shaft at A, fig. 23, and 

a Prony friction brake, having an arm about 3 feet long, made to fit 

the pulley. A spring balance reading to quarters of a pound was 

made fast at one end, the other end being fastened to the arm of the 

brake. The speed of the shaft was found to be too great to be taken 

by a recorder, so a speed counter was used. By turning the nuts on 

the under side of the brake the spring balance could be made to read 

any desired number of pounds, and thus the load on the mill could 

be regulated. By holding the speed counter on the end of the shaft, 

throwing it in gear at the beginning of a mile of wind and throwing 

it out of gear at the end of the mile, the number of revolutions of pulley was found. The time of making the mile was also noted, from 

which wind velocity was found. If u equal the number of revolutions of pulley per mile of wind, L the load as shown by spring 

balance plus load of arm, and R the length of brake arm, we have 

the number of foot-pounds per mile of wind: Foot-pounds=L u 2 n R.

In fig. 27 are given four curves showing the relation between the 

number of foot-pounds per mile of wind and the wind velocity for 

four loads, namely, G pounds, 4 pounds, 2 pounds, and 0 pounds. 

These curves are constructed in the same way as those of figs. 4, 8, 9, 

11, 13, 15, 16, 18, and 20, by drawing a smooth curve among a series 

of points whose ordinates are found from the above equation and 

whose abscissas are the observed velocity of wind, so as to have about 

as many points on one side as on the other. The left, or steep part, 

of each curve is the most difficult to determine, and has a less degree 

of accuracy than the rest of the curve; owing to the velocity being 

low, several minutes are necessary to make a mile, and the wind may 

vary considerably during this time. It may be nearly an average all 

the time and the mill scarcely move, or it may be twice as rapid the 

latter half of the time as the first half, and the number of revolutions 

for the same mean velocity will be quite different in the two cases.

Another reason why the steep part is less accurate is that a very 

little movement to the right or left of this portion will change the 

number of foot-pounds much more than in any other part of the curve. 

The curve A B is for no brake load. The brake was off the pulley; 

no useful work was being done, but the resistance of the moving parts
42 WINDMILLS FOR IRRIGATION. [NO. 8.

of the mill was being overcome. The pull necessary to overcome this 

resistance was found by standing on the platform of the mill and pulling the wind wheel around at uniform low speed with a spring balance. 

This was checked by winding a cord round the circumference of the 

wind wheel, and, standing on the ground, moving the mill when there

130

110

100

VELOCITY OF WIND IN MILES PEB HOUR.

10 15 30 25

TO

60

50

£ 30

20

10

PIG. 27. Diagram showing useful work for different loads of Mill No. 27.

was no wind by pulling on the spring balance attached to this cord. A 

pull of 1|- pounds applied at the circumference (6 feet from center of 

wind wheel) was sufficient to overcome this resistance at a low velocity. Since the brake pulley is geared forward 6 to 1, the number of 

foot-pounds per revolution of brake pulley necessary to overcome this
MURPHY.] DISCUSSION OF RESULTS. 43

resistance is 7.9. The number of foot-pounds per mile of wind for 

other velocities is then easily found from speed of brake pulley.

The greater part-of this curve, A B, fig. 27, is seen to be a nearly 

horizontal straight line, the number of foot-pounds per mile of wind 

required to run the machinery being nearly constant. The other 

three curves of this plate are for useful work only; the useless work 

is not included in them. The highest point of these curves is seen to 

rise and move to the right as the load increases, and the part to the 

right of the highest point is seen to become more and more steep as 

the load increases. A broken line, A K, has been sketched tangent

2.0

VELOCITY OF WIND IN MILES PER HOUR. 

10 15 20 35

1.4

Pio. 28. Diagram showing horsepower for different loads of Mill No. 27.

to these curves. It is the envelope of them and is concave to the horizontal coordinate axis. It would give the relation between footpounds per mile of wind and wind velocity if the load could be 

increased as the velocity increases.

Fig. 28 shows the relation between the horsepower and the wind 

velocity for the four loads 6 pounds, 4 pounds, 2 pounds, and 0 

pounds. They are obtained from the curves of fig. 27 by reducing foot-pounds per mile of wind to horsepower; that is, for any 

velocity of, say, 16 miles per hour and load of, say, 2 pounds, divide
44 WINDMILLS FOR IRRIGATION.

the ordinate a b, fig. 27, by ff (the number of minutes required to 

make the mile), and by 33,000, and we have the corresponding ordinate a' b' of fig. 28.

It is seen from these curves that for any brake load the power of 

the mill increases rapidly as the wind velocity increases, and reaches 

a maximum for some velocity greater than 30 miles per hour. As the 

load increases, the velocity required to start the mill increases rapidly 

and the curve becomes more steep. For a given wind velocity the 

power increases rapidly as the load increases. For a velocity of 30 

miles the power is nearly proportional to the load for loads less than 

6 pounds. It is seen that when the velocity is less than 12 miles a 

4-pound load is too great, and when the velocity is less than 19 miles 

a 6-pound load is too great. The dotted curve D K, which is the 

envelope of these curves, gives the relation between power and wind 

velocity for a constantly increasing load. It is seen that there would 

be a great saving of power by the use of a device which would automatically increase the load as the velocity increases. The horsepower 

would then be given by the curve D K, instead of by one of the other 

curves.

Results of computations of power mills.

6 

K

a 8

26

27 

27 

27 

27

6 

2!

1

26 

27 

27 

27 

27

Name.

Pei

Ae rinotor. 

do^_._

--

.....do. ......

... -_do_......

a> a

A

Lbs. 

6 

6 

4 

2 

0

Owner.

Geo. Gilbert ..... 

E. C. Murphy. . .

.....do ...........

.....do ...........

a> 

.3

00

Ft. 

14 

12 

12 

12 

12

 a

1 

a>

1 

«

Lbs. 

6 

6 

4 

2 

0

Foot-pounds per mile of wind when hourly 

velocity in miles is 

8

22,000 

12,000

Foot-pounds per minute when hourly wind 

velocity in miles is 

8

2,933 

1,600

12

10,000 

9,400 

2,400

16

21,530 

12, 747 

3,040

20

33,833 

29,367 

15,133 

3,667

25

4~7,9l7 

33,667 

17,250 

4,250

30

52,100 

a5,&50 

17,800 

4,850

12

50,000 

47,000 

12,000

16

80,800 

47,800 

11,400

2O

101,500 

88,400 

45,400 

11,000

25

115,000 

80.800 

41i400 

10,200

30

i04,200 

71,700 

35,600 

9,700

Useful work in horse power 

when hourly wind velocity 

in miles is 

8

.089 

.050

12

.303 

.285 

.073

16

313

.653 

.386 

.087

2O

.609

1.028 

.890 

.458 

.111

25

.937

1.451 

1.020 

.523 

.128

30

1.576 

1.086 

.540 

.151

Vane inarea feet. square 

100.2 

72.9 

72.9 

72.9 

72.9

TOTAL ENERGY OF THE WIND.

The curve A B shows the relation between wind velocity and the 

total horsepower possessed by the wind at the temperature of 46° F. 

and the barometric pressure of 28.9 inches. It is found from the relaw V3

tion Horsepower= A - where w is the weight per cubic foot of

2g 5 50

air at this temperature and pressure, A the vane area equals 72.9
MURPtiY.] DISCUSSION OP RESULTS. 45

700

600

ft 500 

w

LOAD 

0246

IN POUNDS ON SPRING BALANCE. 

square feet, V the velocity of wind in feet per second, and g the accelTn p 1

eration of gravity, w was found from the formula w= w0 ^

Po x »

in which T0 = 273° C., w0 = .0807 pounds per cubic foot, p0 = 14.7 

pounds per square inch, T = 281° C., p = 28.9 inches, and C = the 

temperature expressed in centigrade degrees. Substituting these 

values, Horsepower = .00021 V3 .

EFFICIENCY OF MILL.

By dividing any ordinate of a load curve by the corresponding 

ordinate of this curve A B, we have the efficiency of the mill for this 

load and velocity of wind. 

It is easily seen that the efficiency increases as the velocity decreases and as the load 

increases. The maximum 

efficiency is given by the ratio 

of the ordinate of the dotted 

curve to the corresponding 

ordinate of curve A B. This 

efficiency for a load of 2 

pounds and a velocity of 9 5 4oo 

miles per hour is 40 per cent, 

using as wind area the sum 

of the areas of the fans. At 

14 miles with a load of 4 

pounds it is 36 per cent. If 

the load at this velocity be 

reduced to 2 pounds the efficiency is reduced to 24 per 

cent.

Fig. 29 shows the relation 

between load and number of 

revolutions of the brake pulley for velocities of 8, 12,16, 

20, 25, and 30 miles per hour. 

It shows how much the speed is reduced by a given change of 

load. It is seen that for a velocity of 8 miles per hour changing 

the load from 0 to 2 pounds reduces the speed 60 per cent. When 

the velocity is 12 miles, changing the load from 0 to 2 pounds reduces 

the speed about 17 per cent, and changing from 2 to 4 pounds reduces 

it nearly 50 per cent. When the velocity is 16 miles, changing the 

load from 0 to 2 pounds changes the speed very little. When the 

velocity is 20 miles, the speed remains about constant for 2 and 4

300

300

100

FIG. 39. Diagram showing relation between number of 

revolutions of brake pulley per minute and load for 

different wind velocities for Mill No. 37.

1 1. P. Churche's Mechanics of Engineering, p. 611, John Wiley & Sons, New York. Table 

giving results of computations of power mills.
46 WINDMILLS FOE IRRIGATION.

pounds; at 25 and 30 miles the speed remains nearly constant for 

loads from 2 to 6 pounds.

MATHEMATICAL RELATION BETWEEN WIND VELOCITY AND POWER.

The relation between wind velocity and power of windmill is 

expressed graphically by the curves of fig. 28. The mathematical 

expression of this relation is given by Mr. A. R. Wolff on page 30 of 

his book, The Windmill as a Prime Motor, as Lv (or foot-pounds per

second) = - - v( sin a cos a ) cos a, where v=velocity of 

g V c J y

fan, s=surface of fan in feet, c=velocity of wind in feet per second, L=useful wind pressure on fan, d=density of wind, g=acceleration due to gravity, k is a coefficient, and «=the angle that the 

wind makes with surface of fan. It is seen that for a given wind 

velocity, density of air, and wind area, this expression for useful 

work is a function only of the velocity of the moving fan; it is not a 

function of the load on the mill. Fig. 29 shows that for a wind 

velocity of 30 miles per hour, and with a nearly constant velocity 

of wind area (v in the above formula), the load can be more than 

double, and thus the power more than doubled. It is evident, then, 

that however well this formula may give the power of the old Dutch 

mill or other modern mills not back geared, it gives results very much 

in error for a steel back-geared mill. Judging from the results of 

these tests, a formula giving the power of a steel back-geared mill 

should contain a factor which varies as the load on the mill varies.

GENERAL CONCLUSIONS.

1. The pumping power of windmills, or the useful work they do 

when raising water with reciprocating pumps of sizes from 4 to 10 

inches diameter, is small not greater that 0.65 of 1 horsepower for 

12-foot mills, and much less than that claimed for them by some windmill makers.

2. The pumping power of windmills made for irrigating purposes 

is much greater than that of those which have been used for raising 

water for stock purposes.

3. The pumping power of the steel back-geared mills is greater than 

that of the wooden mills working with direct stroke.

4. The power of the Jambo mill is much less except for very high 

wind velocities than that of the steel back-geared mills.

5. Well points produce a greater load on a windmill for a given lift 

and quantity of water than open wells.

6. Perhaps the most important result shown by these tests, and one 

that has not been clearly shown before, as far as the writer has seen, 1

1 Abstract of paper on "'Windmills for raising water," by J. A. Griffiths: Proc. Inst. Civil 

Eng.. Vol. 119,1895, p. 15.
MURPHY.] GENERAL CONCLUSIONS. 47

is the influence of load on mill, or number of foot-pounds per stroke 

of pump on the power of a mill. The influence of this load factor on 

the power can be seen by comparing the power of two pumping mills 

of the same diameter whose loads differ considerably; but it is much 

better shown by the tests of Power Mill No. 26. These tests show that 

for high velocities 25 or 30 miles the power is very nearly proportional to the load on the mill. For 30 miles per hour, a brake load of 

2 pounds gave 0.54 horsepower; a 4-pound load, 1.09 horsepower; and 

a 6-pound load, 1.55 horsepower. The influence of this factor on the 

power is so great that if it is not properly taken into account, it 

obscures the influence of resistance of well points and the working of 

valves of pump or the efficiency of the pump.

7. Another fact brought out by these tests, and which follows as a 

result of the previous ones, is that there should be some automatic 

device for increasing the load on a mill as the wind velocity increases. 

When the velocity is low say 6 miles per hour the load should be 

small enough to enable the wind wheel to run at a rapid rate the rate 

for maximum power and then as the wind velocity increases the load 

should be increased, so 

as not to allow the wheel 

to run at a higher speed. 

This is a very promising field for the inventor.

8. If the load can not 

be automatically increased as the wind velocity increases, then 

the question arises, 

What is the proper or 

most economical load? 

This depends on the velocity of the wind each 

month at the given 

place. During the 

months of July and 

August there are a greater number of hours of low wind velocity than 

during any other two months of the year. The load should be light 

during these months for the greatest power. If the wind velocity is 

known, and the mill is one of the sizes and makes shown in the diagrams, the proper load can easily be computed. The mills in the 

vicinity of Garden, Kansas, would do more useful work if more heavily 

loaded.

It is seen that the useful work that a windmill will do when working under a constant load at all velocities is small, the horsepower 

varying as the first power of the velocity. By some device for autoFIG. 30. Diagram of forces acting on vane of mill.
48 WINDMILLS FOR IRRIGATION. [NO. 8.

matically increasing the load as the wind velocity increases, the power 

may be much increased at high velocities, and will then vary as the 

second power of the velocity. Even with this device for increasing 

power there is still a great difference between the power possessed 

by the wind and the power developed by the mill, and this difference 

increases as the velotirty increases.

The reason why the windmill utilizes so small an amount of the 

energy of the wind may be seen from the following: Let A B, fig. 30, 

be a strip taken from the outer end of one fan of a windmill. It is 

curved, but for this purpose it may be considered a plane. This strip 

makes an angle a with the absolute direction of the wind. C represents the amount and direction of the wind; Y represents the 

amount and direction of the velocity of the surface A B. Then the 

relative velocity of the wind that is, its velocity with respect to the 

moving surface A B is V, the diagonal of the parallelogram constructed on V and C as sides, V makes an angle /? with the sloping 

surface A B. If V=0 that is, if the wheel is held so that it can 

not revolve the angle /?=a. As V increases /? grows less and 

less, and finally becomes zero, in which case V is parallel to surface 

A B. In this case the surface receives no pressure from the wind 

this portion of the fan is not utilizing any of the energy of the wind. 

If Vbe still further increased, ft becomes negative, and the wind pressure is on the opposite side of A B. This portion of the fan is then 

doing work on the wind instead of the wind doing work on the fan. 

The effective wind area of a fan being the projection of the fan on a 

plane at right angles to the relative velocity of wind over it that is, 

to V it is seen that as V increases the effective wind area decreases. 

The energy which the fan takes from the wind is proportional to the 

.effective wind area. It is seen, then, that this reduction of effective 

wind area is the reason why the efficiency is low at high velocities. If 

this effective wind area could be kept constant by some device for 

changing the angle of the fans, the relation between wind velocity and 

horsepower might vary nearly as the third power of the wind velocity.

In this discussion we have not taken into account the reduction of 

wind area due to the wind wheel swinging out of the wind, or "regulating." The mill can be built strong enough so that it will not need 

to regulate for velocities less than 30 miles an hour.
INDEX.

Page. 

Aermotors, views of . .... 15,16,18,36,33

descriptions of....... 16-17,18,30,33,35,33

Anemometer, measurement of wind velocity by........_- - . ---- 13-13

view of.-...---....--...-----...-----.-. 14

Defender mill and elevator, view ojf....... 33

Dodge, Kansas, mean wind movement at. 39 

Frizell cylinder, view of working parts of. 33 

Garden, Kansas, windmill pumping plants

near,. ---- .-.....--.....-...- 9

wells near.-.----.------....-_..- - 10

Gause pump, view of.....---....--........ 10

descriptions of___ --._..-- -._-_._. 35,30 

Gem windmill, descriptions of _....- 19,35,36,37

view of working parts of.........---.. 30

view of.---..----.---..-.--...------.--- 38

Griffiths, J. A., cited..... ............... 46

Halliday windmill, description of -,... 3o, 39-30

view of working parts of -........-...- 38

view of.-....--......-....--...-....... 30

Ideal windmills, descriptions of.. 17,33,33,34,27

views of------ _____.----__------.-- -- 18,34

view of working parts of . ------- 21

Jumbo windmill, view of-.....-- ------ 36

description of,.._--_...........-------- 38-39

Kansas, windmill pnmping plants in..... 9

Kansas, wells in............................ 10

Mills, efficiency of_..--__. _-_.__-L___- _ 45-40 

Mills, pumping, discussion of work of.... 39-40

diagram showing useful work for different loads of.-----.----..---.--..-. 42

results of computations of............ 44

power, discussion of work of......... 40-44

Newell, F. H., letter of transmittal by. - - 7 

Power mills, views of.--.-.---_--._._ 30,31,33

description of.......................... 31-33

IRK 8 4

Page.

Powder mills, results of computations of. 44 

discussion of work of..............._ 40-44

Pumping mills, results of measurements

and computations of ................ 34

comparison of back-geared and direct 

stroke......--........---.......-,.... 37-38

discussion of work of...--.---._-- .- 39-40 

Pump strokes and wind velocity, relalationsbetween .............._....... 13-14

Star windmill, description of......--...-- 30-33

Stone, R. G., instrument for measuring 

mean pull of pump devised by ---------- 38

Stone pumps, descriptions of............. 10-13,

16,17,19, 30, 35, 37, 39-30 

view of........._-.-....._----....-. 15

views of valves of -.__...... --------- 16

Wells near Garden, Kansas, description of 10 

Wind velocity, measurement of.___._____ 13-13

relation between strokes of pump and. 13,35 

diagrams showing relation between 

pump strokes and ................... 14,

17,18,19,30, 33, 24, 35, 37, 29 

relation between horsepower and... 35-37,

44-45, 46

diagram showing relation between 

horsepower and---..--_----- --_.... 36

total energy of......................... 44-45

diagram of forces acting on vane of 

mill...... --.--...-.-. -----.- 47

Wolff, A.R., cited......................... 9

Woodmanse Mogul windmill, view of

working partsof.............._ . 11

. view of __. __..._.-_---,___ ..._--_- 14 

description of.......................... 14-15

Woodmanse pump, description of-------- 14-15

sectional view of....................... 12

49
1895.

Sixteenth Annual Report of the United States Geological Survey, 1894-95, Part II, 

Papers of an economic character, 1895, octavo, 598 pp.

Contains a paper on the public !ands and their water supply, by F. H. Newell, illustrated 

by a large map showing the relative extent and location of the vacant public lands; also a 

report on the water resources of a portion of the Great Plains, by Robert Hay.

A geological reconnoissance of northwestern Wyoming, by George H. Eldridge, 

1894, octavo, 72 pp. Bulletin No. 119 of the United States Geological Survey; 

price, 10 cents.

Contains a description of the geologic structure of portions of the Big Horn Range and 

Big Horn Basin, especially with reference to the coal fields, and remarks upon the water 

supply and agricultural possibilities.

Report of progress of the division of hydrography for the calendar year 1893-94, 

by F. H. Newell, 1895, octavo, 176 pp. Bulletin No. 131 of the United States 

Geological Survey; price, 15 cents.

Contains results of stream measurements at various points, mainly within the arid region, 

and records of wells in a number of counties in western Nebraska, western Kansas, and 

eastern Colorado.

1896.

Seventeenth Annual Report of the United States Geological Survey, 1895-96, Part 

II, Economic geology and hydrography, 1896, octavo, 864 pp.

Contains papers by G. K. Gilbert on the underground water of the Arkansas Valley in 

eastern Colorado; by Prank Leverett on the water resources of Illinois; and by N. H. Darton on a reconnoissance of the artesian areas of a portion of the Dakotas.

Artesian-well prospects in the Atlantic Coastal Plain region, by N. H. Darton, 

1896, octavo, 230 pp., 19 plates. Bulletin No. 138 of the United States Geological Survey; price, 20 cents.

Gives a description of the geologic conditions of the coastal region from Long Island, 

N. Y., to Georgia, and contains data relating to many of the deep wells.

Report of progress of the division of hydrography for the calendar year 1895, by 

F. H. Newell, hydrographer in charge, 1896, octavo, 356 pp. Bulletin No. 140 

of the United States Geological Survey; price, 25 cents.

Contains a description of the instruments and methods employed in measuring streams 

and the results of hydrographic investigations in various parts of the United States.

1897.

Eighteenth Annual Report of the United States Geological Survey, 1896-97, Part 

IV, Hydrography, 1897, octavo, pp. (In preparation.)

Contains a progress report of stream measurements for the year 1896, by Arthur P. Da vis, 

and four other papers relating to hydrography. The first of these is by_ Prank Leverett, 

and relates to the water resources of Ohio and Indiana, especially as obtained by wells; the 

next is by N. H. Darton, on the artesian waters of South Dakota, being supplementary to 

his paper in the Seventeenth Annual; f oltowing this is a fully illustrated paper, by James 

D. Schuyler, on water storage, mainly for irrigation and the construction of dams; the last 

pa^er, by Robert T. Hill, describes the artesian conditions of a portion of Texas in the 

vicinity of San Antonio.

Water Supply and Irrigation Papers.

This series of papers is designed to present in pamphlet form the results of stream measurements and of special investigations. A list of these, with other information, is given on 

the outside (or fourth) page of this cover.

Survey bulletins can be obtained only by prepayment of cost as noted above. 

Postage stamps, checks, and drafts can not be accepted. Money should be transmitted by postal money order or express order, made payable to the Director of 

the United States Geological Survey. Correspondence relating to the publications 

of the Survey should be addressed to The Director, United States Geological 

Survey, Washington, D. C.
WATER-SUPPLY AND IRRIGATION PAPERS.

1. Pumping water for irrigation, by Herbert M. Wilson, 1896.

2. Irrigation near Phoenix, Arizona, by Arthur P. Davis, 1897.

3. Sewage irrigation, by George W. Rafter, 1897.

4. A reconnoissance in southeastern Washington, by Israel C. Russell, 1897.

5. Irrigation practice on the Great Plains, by E. B. Cowgill, 1897.

6. Underground waters of southwestern Kansas, by Erasmus Haworth, 1897.

7. Seepage waters of northern Utah, by Samuel Fortier.

8. Windmills for irrigation, by E. C. Murphy. 

In preparation:

9. Irrigation near Greeley, Colorado, by David Boyd.

10. Irrigation in Mesilla Valley, New Mexico, by F. C. Barker.

11. River heights for 1896, by Arthur P. Davis.

12. Water resources of southeastern Nebraska, by Nelson Horatio Darton.

In addition to the above, there are in various stages of preparation other papers 

relating to the measurement of streams, the storage of water, the amount available 

from underground sources, the efficiency of windmills, the cost of pumping, and 

other details relating to the methods of utilizing the water resources of the country. Provision has been made for printing these by the following clause in the 

sundry civil act making appropriations for the year 1896-97:

Provided, That hereafter the reports of the Geological Survey in relation to the 

gauging of streams and to the methods of utilizing the water resources may be 

printed in octavo form, not to exceed 100 pages in length and 5,000 copies in number; 1,000 copies of which shall be for the official use of the Geological Survey, 

1,500 copies shall be delivered to the Senate, and 2,500 copies shall be delivered to 

the House of Representatives, for distribution. (Approved, June 11,1896; Stat. L., 

vol. 29, p. 453.)

The maximum number of copies available for the use of the Geological Survey 

is 1,000. This quantity falls far short of the demand, so that it is impossible to 

supply all requests. Attempts are made to send these pamphlets to persons who 

have rendered assistance in their preparation through replies to schedules or donation of data. Requests specifying a certain paper and stating a reason for asking 

for it are attended to whenever practicable, but it is impossible to comply with 

general demands, such as to have all of the series sent indiscriminately. 

Application for these papers should be made either to Members of Congress or to 

THE DIRECTOR,

UNITED STATES GEOLOGICAL SURVEY,

Washuigton, D. C.