DEPARTMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, DIKECTOR

BTJLI/ETIN 395

RADIOACTIVITY OF THE THERMAL WATERS 

OF YELLOWSTONE NATIONAL PARK

BY

HERMAN SCHLUNDT

AND

RICHARD B. MOORE

WASHINGTON

G O V JO R N M 10 N T P It I N T ING OFFICE

1909

CONTENTS.

Page

Introduction................................................................ 5

Purpose of the report................................................... 5

Waters in Yellowstone Park...............'.............................. 5

Scope of the investigation.............................................. 6

General plan of work................. '. ................................. 6

Acknowledgments...................................................... 7

Apparatus......................................:................-......... 7

Description of electroscopes...... J...................................... 7

' Standardizing the electroscopes. ........................................ 9

Electric capacity....................................................... 12

Methods of procedure....................................................... 13

Field examination of gases.............................................. 13

Field tests of waters............:............:......................... 16

Testing of solids........................................................ 17

Results of the experiments.................................................. 18

General statement...................................................... 18

Example showing method............................................. 18

. Radioactivity of gases..............,..............'.................... 20

Radioactivity of waters................................................. 22

Radioactivity of water residues, spring deposits, and rock samples ........ 25

Summary of radioactivities............................................ 27

Discussion of results...... ^................................................. 28

Gas activities.......................................................... 28

Thorium emanation............................................... . 28

Relative activity. .................................................. 28

Gases from European springs........................:...............' 29

Helium not determined....................................:......,.... 29

Activity of waters...................................................... 30

Inferences from different results.................................... 30

Comparison with European waters.................................. 31

Radium content of deposits of rocks.................................... 32

Comparative activities of different rocks ............................ 32

Radioactive equilibrium............................................ 33

Estimate of age of deposits.'......................................... ,33

Comparative test for uranium by analysis...................'........ 34

Relation to hydrothermal activity.....................'.................. 34

3
ILLUSTRATIONS.

PLATE I. Grotto Geyser, Yellowstone National Park......................... 5

II. Norris Geyser Basin....'.........'................................. 18

III. A, Old Faithful Geyser, Upper Geyser Basin; B, Hot Spring, Norris 

Geyser Basin, where thorium was first discovered in the United 

States......................................................... 28

IV. Morning Glory Pool, Upper Geyser Basin......................... 32

FIGURE 1. Electroscope................................................... 8

2. Apparatus for separating emanation from uraninite................ 10

3. Apparatus for qualitative tests in the field......................... 13

4. Curves showing difference in the radioactivity of gases containing

(A) thorium and radium emanation and (B) radium emanation... 14

5. Apparatus for collecting gas in the field.......................... 15

 6. Detail of apparatus for collecting gas in the field.................. 15

7. Decay curve of radium emanation............................... 16

4
U. S. GEOLOGICAL SURVEY

GROTTO GEYSER.
RADIOACTIVITY OF THE THERMAL WATERS OF 

YELLOWSTONE NATIONAL PARK.

By HERMAN SCHLUNDT and RICHARD B. MOORE.

INTRODUCTION. 

PURPOSE OF THE REPORT.

During the summer of 1906 we conducted a series of field tests for 

the United States Geological Survey with the object of determining 

the radioactive properties of the thermal waters of the Yellowstone 

National Park. In connection with the field work, samples of deposits formed by the springs, some typical rock specimens, and a number 

of water residues were obtained. In this bulletin the quantitative data 

of the investigation are presented in a series of tables. An account 

of the methods of experiment in both field and laboratory precedes 

the presentation of results, and a discussion follows. We have indicated a possible application of some of the data to a geologic question the age of some of the spring deposits; but no systematic 

attempt has been made to relate the facts of radioactivity to the 

hydrography of the region or to the geology of the park. Since our 

experiments were conducted chiefly from the chemist's point of view, 

we have limited our discussion to pointing out the more important 

characteristics and relations of the data, and comparing them with 

data on radioactivity in other regions of hydrothermal activity.

WATERS IN YELLOWSTONE PARK.

The thermal waters of the national park are classified by Arnold 

Hague under three heads, on the basis of incrustations formed by 

the springs and chemical analyses of some of the waters made by 

Gooch and Whitfield: a (1) Calcareous waters carrying relatively 

large quantities of calcium carbonate in solution; (2) siliceous acid 

waters which usually carry free acid in solution and possess an astringent taste; (3) siliceous alkaline waters. In all, about 4,000 hot 

springs are found in the park and about a hundred geysers.

a Gooch, F. A., and Whitfield, J. E., Analyses of waters of the Yellowstone National Park: Bull. 

U. S. Geol. Survey No. 47, 1888.

5
O RADIOACTIVITY OF THERMAL WATERS

There is but one important group of calcareous waters in the park, 

namely, Mammoth Hot Springs, near the northern boundary. In 

the course of their underground flow these waters pass through Jurassic and Cretaceous limestones and become charged with carbon 

dioxide and mineral matter, which is deposited as travertine. A 

series of terraces extend more than a mile up a valley and to a height 

of 1,300 feet. The springs of this locality differ considerably in temperature, the maximum being 74° C., about 18° under the boiling 

temperature of water at this altitude.

Acid waters occur in the following localities among those we vis- 

"ited: Norris basin, Shoshone basin, Heart Lake basin, Crater Hills, 

Tower Falls, Mount Washbum, Mud Volcanoes near Yellowstone 

River, and Grand Canyon of the Yellowstone.

Alkaline waters predominate in the regions of geyser activity. 

These waters deposit an incrustation of amorphous silica. Springs 

of this class w'ere tested at Upper and Lower Geyser basins, Excelsior 

basin, Shoshone basin, Heart Lake basin, and West Thumb of Yellowstone Lake.

SCOPE OF THE INVESTIGATION.

The field tests extended over a period of two months, during which 

all the principal basins of thermal activity were visited. The spring 

waters examined embrace the different types found in the park and 

include water from a number of cold springs. The aim was to test 

one or more of each type at each basin visited. Wherever gases 

were evolved from a spring, these also were tested for their radioactive properties. About eighty quantitative tests were made of 

waters and forty of gases, besides nearly ninety tests of gases largely 

of a qualitative nature. In the laboratory some fifty solids, consisting of spring deposits, water residues, and rock samples, were 

examined quantitatively for the radium content.

GENERAL PLAN OF WORK.

The determinations for radioactivity were all made by the electrical method. Several electroscopes of the C. T. R. Wilson type, 

as modified in some details by Doctor Boltwood and ourselves for 

this kind, of work, were employed in both field and laboratory tests. 

The procedure in the field was generally as follows: A qualitative 

test for radium and thorium emanation was first conducted on the 

escaping gas from the spring. This was followed by a quantitative 

determination of the radium emanation present in the gas. Meanwhile a sample of the spring deposit was collected and a sample of 

water taken. 'Incidentally the temperature of the water was taken 

and its reaction toward litmus paper tested. At the field laboratory 

the quantity of radium emanation in the sample of water collected
OP YELLOWSTONE NATIONAL PABK. 7

was determined, after which the water was evaporated to dryness. 

The residue thus obtained and the sample of deposit made by the 

spring were subsequently examined for their radium content in a 

chemical laboratory.

ACKNOWLEDGMENTS.

The United States Geological Survey defrayed the greater portion 

of the expense connected with the field tests of this investigation. 

The Northern Pacific Railway furnished transportation between St. 

Paul and Gardiner, Mont. The University of Missouri and Butler 

College loaned most of the scientific apparatus used in the field tests, 

and the determinations of radium present in the spring deposits and 

rock samples were conducted in the chemical laboratories of these 

institutions. The field work came under the direction of C. W. Hayes 

and Arnold Hague, of the United States Geological Survey. Doctor 

Hague also placed at our disposal several specimens of typical 

rocks, which were used in determining the radium content of rocks. 

Maj. John Pitcher, U. S. Army, extended numerous facilities that 

materially aided in the field experiments. Capt. William H. Forsythe, U. S. Army, collected several samples of travertine for us at 

Mammoth Hot Springs. The noncommissioned officers stationed 

at the military posts throughout the park assisted in various ways.

APPARATUS. 

DESCRIPTION OF ELECTROSCOPES.

Three air-tight electroscopes of the C. T. R. Wilson type were 

employed in the field and laboratory tests. Two of these we had 

used in a previous investigation on the radioactivity of waters.0 

These instruments were constructed in the main according to the 

specifications given by Boltwood. 6 Figure 1 shows one of the electroscopes but does not show the reading microscope for observing 

the fall of the leaf. The instrument consists of a rectangular brass 

frame 15 by 10 by 6 4 centimeters, fitted on the front and back with 

pieces of plate glass. On the top, the frame carries a short piece of 

wide glass tubing (T) surmounted by a threaded brass ring (R), into 

which a removable brass cap (C) screws. A short piece of glass 

tubing passes through a hole in the cap and a brass rod (r) is cemented 

in the glass tube by means of sulphur or wax. The lower end of the 

brass rod extends into a rod of sulphur, which serves as the insulating material to support the leaf system. The plate (p) to which 

the leaf is fastened is embedded for a short distance in the other end. 

of the sulphur rod. A special feature of the electroscope is the device

a Jour. Phys. Chem., vol. 9, 1905, p. 321.

6 Am. Jour. Sci., 4th ser., vol. 18,1904, p. 97.
8 RADIOACTIVITY OF THERMAL WATERS

for charging it. a A piece of soft iron wire (w) is suspended from a 

hook on the brass rod (r) which projects out through the screw cap. 

The wire extends just below the sulphur insulator and terminates in 

a right-angle bend. In its normal position the wire does not touch 

the plate carrying the leaf, but by bringing a magnet near the wire,

FIGURK 1. Electroscope.

it can be deflected so as to make metallic contact between the rod (r} 

and the plate (p). All of the brass joints are soldered and the other 

joints are made air-tight by means of hot wax, except that between 

the brass ring and cap, where a rubber washer excludes the air. The 

electroscope is provided with two good brass stopcocks.

a The same device was used by Strutt, Phil. Mag., 6th sen, vol. 5,1903, p. 680; and by Boltwood, loc. cit
OF YELLOWSTONE NATIONAL PAEK. 9

Aluminum leaf was used in the instruments. It was readily and 

firmly fastened to the carrying blade by moistening the upper portion of the blade and then pressing it firmly against the leaf. The 

sulphur rod and the aluminum leaf successfully withstood the transportation by rail and in the field. In two of the electroscopes the 

original leaf served throughout the entire series of field experiments. 

The volume of the electroscopes was, respectively, 490, 590, and 600 

cubic centimeters. A rod of vulcanite about 20 centimeters long was 

used for charging. After metallic connection between the leaf system and the projecting rod had been made, the charged vulcanite 

was touched to the brass rod, and by gentle rubbing, the desired potential on the leaf system was produced. After withdrawing the vulcanite the rod and cap were earthed for an instant.

Each electroscope was fastened securely to a wooden base. The 

fall of the leaf'was observed by means of a microscope firmly supported by a brass holder which was likewise screwed to the wooden 

base. The glass scale in the eyepiece was divided into ten divisions 

and each of these was again divided into tenths. The diameter of 

the field corresponding to the hundred small divisions of the scale 

was approximately 5.2 millimeters for each of the microscopes. 

The rate of fall of the leaf was generally obtained by noting the time 

required for the leaf to fall 60 small divisions between the same two 

points of the scale. The time interval was measured by means of a 

stop watch recording fifths of a second. To secure uniform and ready 

adjustment of the instruments for the field tests a circular level was 

attached to the base. Suitable carrying cases were constructed for 

the electroscopes to facilitate their safe transportation in conducting 

the outdoor experiments.

STANDARDIZING THE ELECTROSCOPES.

To make quantitative activity measurements by means of electroscopes, each instrument must be standardized. The method of 

standardizing employed was the one first proposed by Boltwood,a 

which we had adopted in our earlier electroscopic determinations of 

radium emanation in waters. 6 Strutt has followed a similar procedure in his extensive investigations on the radium content of rocks 

and spring deposits. 0 The method is based upon the well-established 

fact that the radium present in natural uranium minerals stands in 

constant ratio to the uranium. Rutherford and Boltwood d have 

recently redetermined this ratio and found that one gram uranium is 

in radioactive equilibrium with 3.8 X10" 7 grams radium. If then the 

emanation from a small weighed quantity of a uranium mineral,

a Am. Jour. Sci., 4th ser., vol. 18, 1904, p. 381.

6 Jour. Phys. Chem., vol. 9,1905, p. 320; Trans. Am. Electrochem. Soc., vol. 8,1905, p. 291.

c Proc. Roy. Soc., vol. 77, 1906, p. 472.

d Am. Jour. Sci., 4th ser., vol. 22, 1906, p. 1.
10 RADIOACTIVITY OP THERMAL WATERS

whose percentage of uranium is known from a chemical analysis, be 

introduced into the electroscope, and the rate of fall of the leaf noted, 

the data are at hand from which a constant for the electroscope may 

be calculated that shall express the uranium (or radium) required to 

produced a fall of the leaf one division in unit time.

The operation of standardizing was carried out as follows: The 

apparatus used for separating and collecting the emanation is shown

in figure 2. A small quantity 

of a standard sample of powdered uraninite containing 68.9 

per cent uranium was weighed 

out and put in the flask (F), of 

about 50 cubic centimeters capacity. Generally 15.7 milligrams of uraninite was used, as 

the emanation separated from 

this quantity of the mineral 

upon solution . represents the 

total emanation associated with 

10 milligrams uranium. A rubber stopper fitted with a small 

dropping funnel and a short delivery tube was then inserted in 

the flask and connections were 

made with the gas burette (B), 

which had previously been filled 

with freshly boiled distilled 

water, to which a few cubic 

centimeters of sodium hydroxide had been added. A few 

cubic centimeters of diluted 

nitric acid was then poured into 

the drop funnel; the leveling 

reservoir of the gas burette was 

lowered below the level of the 

acid in the funnel; and then by 

opening the pinchcock (c) and 

the stopcock of the funnel most of the 'acid was allowed to flow into 

the flask. The stopcock was then closed, the leveling reservoir 

replaced, and the flask gently heated until the uraninite had dissolved. When any gas collected in the stem of the funnel during 

this operation it was displaced by water introduced through. the 

funnel. By withdrawing the flame for a moment sufficient water 

was allowed to flow into the flask to continue the boiling for ten 

minutes. The gas collected in the burette, after standing for ten

FIGURE 2. Apparatus for separating emanation from 

uraninite.
OF YELLOWSTONE NATIONAL PARK. 11

minutes, was then introduced into the electroscope, which had previously been partly exhausted, to be standardized. After three hours, 

the time in which the activity attains a maximum, the rate of leak 

was determined.

The standardizing record of one of the electroscopes, which is 

designated in our journal as No. 1, is given below in Table 1. The 

quantity of uraninite used in each experiment was 15.7 milligrams. 

Determinations numbered 3 and 4 were conducted in Yellowstone 

Park in the field laboratory, and the others were made in the chemical. 

laboratory of the University of Missouri. The samples of uraninite 

used for standardizing in the park were carefully weighed out and 

sealed in small glass tubes before we started for the field work. The 

first column in the table gives the number of the experiment; the 

second, the date on which it was conducted; the third, the number of 

scale divisions the leaf fell per minute at the time of maximum 

activity three to three and one-half hours after the introduction of 

the gas. The normal air leak of the electroscope, 0.15 division per 

minute, has been deducted from the readings. The last column gives 

the constants computed for the electroscope. These values represent 

the quantity of uranium that would cause a fall of the leaf of one 

scale division per minute, if all of the emanation produced remained 

in the sample. In this particular sample of uraninite, 7.6 per cent 

of the emanation is continuously lost at room temperatures. The 

quantity of uraninite. used in the experiments, however, 15.7 milligrams, contains the maximum quantity of emanation that would be 

found associated with 10 milligrams of uranium. The sample taken 

contains 10.8 milligrams of uranium. Hence the quantity of uranium 

responsible for a leak of one division per minute if all the emanation 

produced were retained is obtained by dividing 10 milligrams by the 

observed leak per minute.

TABLE 1. Standardizing record of electroscope No. 1.

Number.

I................................................................

2................................................................

3................................................................

5. ...............................................................

6................................................................

7 .................................................. :°. ............

Date.

June 28,1905

Aug. 15,1905

July 19,1906

Aug. 24,1906

Nov. 14,1906

Mar. -8,1907

May 22,1907

Observed 

leak (divisions per 

minute).

44.1

45.0

35.5

37.0

48.0

42.8

45.7

Uranium 

per division per 

minute 

(grams XlO-^t).

2.27

2.22

2.88

2 711

2.07

o oc

2 18

The table shows that the constants obtained in the park are approximately 25 per cent higher than the average of the values obtained at 

Columbia, Mo. The lower density of the air at the higher altitude is
12 EADIOACTIVITY OF THERMAL WATERS

an important cause of this difference. The value 2.8X1CT4 was 

used for this electroscope in converting scale readings taken in the 

field to the uranium standard. The radium constant of the electroscope during the field tests was the' product of 2.8X10"4 and 

3.8 XlO-7 , or 10.64 X10~U .

In the field the constant for electroscope No. 2 was found to be 

7.7X10"4 grams uranium and for electroscope No. 3 the value was 

1.52 X 10~4 grams uranium for a leak of one scale division per minute.

ELECTRIC CAPACITY.

Inasmuch as some investigators, chiefly those on the continent of 

Europe, have expressed their quantitative results for the radioactivity of water and gas samples in electrostatic units, we have 

standardized two of our electroscopes in C. G. S. units. We are 

thereby enabled to express our values in absolute units and to compare the activities obtained with those given for some of the wellknown thermal waters of foreign countries.

In expressing the radioactivity of waters, the standards proposed 

by Curie and Laborde a and by Mache 6 have been generally adopted. 

The activity is the value obtained in electrostatic units for the saturation current produced by the radium emanation present per liter of 

water. For gases the saturation current produced by a liter of the 

gas is given as its radioactive value. Mache, in expressing the value 

of activities, deducted from the observed values the current due to the 

disintegration products of the radium emanation. The values given 

by Curie and Laborde represent approximately the total maximum 

activity, which includes the activity of the disintegration products 

of the emanation.

To express the saturation current in electrostatic units two quantities must be determined (1) the rate of fall of the leaf in volts per 

unit of time and (2) the electric capacity of the leaf system. In 

making our electroscopic readings we found the number of divisions 

the leaf fell per minute. . To convert these readings into volts it is only 

necessary to calibrate the scale in the eyepiece of the reading microscope 

between the two points for which readings were generally made. This 

operation was conducted as follows: The glass plate on the back of 

the electroscope was replaced by one of cardboard, which was provided 

with an opening about 1.5 centimeters square, opposite the point 

where the leaf is attached to the carrying blade. The leaf system 

was then connected through the opening in the cardboard to one 

pole of a set of small storage batteries and the case of the electroscope 

to the other pole. The positions of the leaf corresponding to several 

voltages between 300 and 400 were then noted. In this way it was

oCompt. Rend., vol. 138, p. 1150. 

. bSitzungsber. K. Akad. Wiss., Wien, Math.-nat. Klasse. Abt. 2a, vol. 113, pp. 1S29-1352.
OF YELLOWSTONE NATIONAL PARK. 13

found that one small division of the scale of electroscope No. 1 represented 1.24 volts, and for electroscope No. 2 one division represented 

2.80 volts. The electric capacity of the electroscopes was determined by means of a Harms standard 

condenser whose capacity was 42.5 centimeters. The procedure given by Harms0 

was carefully followed. Connections with 

the leaf system were again made through 

the opening in the cardboard. The capacities of the instruments were small; 

that of electroscope No. 1 was found to 

be 2.81 centimeters and that of No. 2, 

3.51 centimeters. The leaf system of 

electroscope No. 1 had the following dimensions: The aluminum leaf was 1.0 

centimeter wide and 5.4 centimeters long, 

and it was fastened to a blade 0.9 centimeter wide and 6.2 centimeters long.

METHODS OF PROCEDURE. 

FIELD EXAMINATION OF GASES.

From many of the springs in the park 

gases escape with the issuing water. In 

some instances the evolution of gas from 

the hot water is so copious as to give the 

appearance of boiling. It is also not uncommon to see gases bubbling up in considerable quantity at certain points in 

the pools of hot water that dot the sinter 

plain in most of the different basins of ther- - mal activity. Systematic tests were conducted with the escaping gases throughout the series of field experiments. The 

gas activity was generally the first determination made. It was conducted at the 

spring and consisted of two parts: (1) A 

qualitative test for the detection of thorium emanation as well as radium emanation; (2) a quantitative determination of 

the raclium emanation present in the gas.

The principal parts of the apparatus used in the qualitative test are 

shown in figure 3: A glass collecting funnel (F).12 centimeters in diamoPhys. Zeitschrift, vol. 5, pp. 49-50.
14 RADIOACTIVITY OF THERMAL WATERS

eter, a rubber hand bellows (P), a drying tube (T) containing strong 

sulphuric acid, and one of the electroscopes (E) were connected in 

series by rubber tubing. By operating the hand bellows the water 

gas collecting in the funnel was gradually made to displace most of the 

original air in the electroscope. One to five minutes was generally 

required for this operation, the time depending upon the rate at which 

the gas collected in the funnel. When 1 to 2 liters of gas had been 

passed along the circuit, the pumping was stopped and the -cocks 

of the electroscope closed. The leaf was then quickly charged and 

readings taken on its rate of fall by means of a stop watch and

TIME IN MINUTES'

FIGUEE 4. Curves showing difference in the radioactivity of gases containing (A) thorium and radium 

emanation and (B) radium emanation.

the reading microscope. By taking readings at suitable intervals 

for five to ten minutes the presence of thorium as well as radium 

emanation could be detected. Sometimes the leaf was charged 

before the transfer of gas through the electroscope was interrupted, 

so that readings could be taken at the instant the leaf appeared in the 

field of the microscope. By the latter procedure the relative activities of the thorium and radium emanation in the electroscope may 

be more readily obtained.

In figure 4 the points for curve A represent a series of readings obtained with a gas containing both thorium and radium emanation, and
OF YELLOWSTONE NATIONAL PAKK. 15

FIGURE 5. Apparatus for collecting gas in the field.

curve B represents the data for a gas containing only radium emanation. The activity is given in an arbitrary scale for the time in minutes. In the gas containing both emanations the activity drops very 

rapidly at first, falling to approximately half value in a minute the 

characteristic rate of decay of thorium emanation. The activity remaining after five minutes mainly represents that of the radium emanation, showing its characteristic initial rise; as in curve B. After 

readings had been taken ____

for ten minutes the gas in i - I - *' ~~\ 

the electroscope was blown, 

out with the hand bellows to 

avoid the accumulation of 

the disintegration products 

of the emanation. After

half an hour the instrument

was generally ready for another test.

If the escaping gas was 

found to be active, a known volume was collected over water and 

this was introduced into an electroscope, which had previously been 

partially exhausted, for a quantitative determination of the radium 

emanation. The device generally .employed for collecting the gas is 

shown in figure 5. A collecting funnel and a graduated cylinder 

attached to a pole were filled with water and then inverted over 

^______, the escaping gas. When 50 to 100 cubic 

centimeters of gas had collected in the 

cylinder, it was brought within arm's reach, 

the funnel removed under water, the cylinder transferred to a small pneumatic trough, 

and the whole removed from the pool to 

 cool. To hasten the cooling, the trough 

was oftentimes placed in a larger vessel 

of cold water. After ten minutes the temperature of the water was taken and the 

volume of the gas read. In the meantime 

a rubber tube supplied with a pinchcock 

was introduced up the cylinder, as shown 

in figure 6. The gas was then transferred to the partially exhausted 

electroscope with the drying train in circuit. The water gas remaining in the train and tubing was swept into the electroscope by 

admitting outside air until atmospheric pressure was restored. The 

rate of fall of the leaf was then taken at intervals during several 

hours following. The maximum activity, reached about three hours 

after the introduction of the gas, was made the basis of calculations

FIGURE 6. Detail of apparatus for 

collecting gas in the field.
16 RADIOACTIVITY OF THERMAL WATERS

in these measurements. Figure 7 represents the results obtained in 

one of these determinations. After four hours (point B on the 

curve) the gas was blown out. The rapid rate of decay of the induced activity, as well as the initial rise, are characteristic of radium 

emanation.

FIELD TESTS OF WATERS.

In almost all the tests the determination of the activity of the water 

samples consisted in a quantitative measurement of the radium emanation in a fresh sample of water. The emanation dissolved in a 

known volume of water was separated by boiling in a form of apparatus 

which had been used in earlier investigations on the radioactivity of

loo

-30

40

0,1 2 3 4 5 6 7

TIME IN HOURS

FIGURE 7. Decay curve of radium emanation.

waters. The apparatus is figured and fully described in the Journal 

of Physical Chemistry, volume 9, pp. 324-326. Several parts of the 

apparatus were modified to adapt it to field conditions. Metal vessels were substituted for the glass ones formerly used as leveling reservoirs. The gas burette for measuring the volumes of the separated 

gases was rarely used. The heating was done with a small wood 

fire. The boilers used were provided with bails and also served as 

collecting vessels. A small quantity of caustic soda was generally 

added to the water sample before boiling to fix the carbon dioxide 

carried by the waters.

About ten minutes after boiling had ceased the separated gas was 

drawn into one of the standardized electroscopes, which had pre-
OF YELLOWSTONE NATIONAL PAEK. 17

viously been partially exhausted by means of a hand suction pump. 

The activity was then ascertained in the usual way by noting the rate 

of fall of the charged leaf at intervals of fifteen to thirty minutes for 

several hours. The maximum leak, obtained three and one-half 

hours after the introduction of the gas, was made the basis for calculating the activity of the water sample.

The presence of radium emanation in a natural water does not necessarily indicate the presence of dissolved radium salts. Being a gas, 

the emanation found in a water sample may simply have diffused into 

it in the course of its underground flow. Such a water, however, has 

only temporary activity, for the emanation when separated from its 

parent radium decays rapidly, falling to half value in about four days, 

one-fourth value in eight days, and so on, until at the end of a month 

the activity has practically disappeared. If radium salts are present 

the water sample will still be radioactive after standing in a sealed 

vessel for a month and the residue after evaporation will also be 

radioactive. The presence of radium salts may be established by 

either of two methods (1) by an examination of the residue obtained 

by evaporation, or (2) by storing the sample from which the emanation has been expelled by boiling, and at the end of a week or two 

again determining the emanation that has accumulated. As our 

facilities for storing waters were limited we evaporated the samples 

and reserved the residues for examination in the laboratory after our 

return from the park. The water was evaporated .on a camp stove 

in iron bowls of about 2 liters capacity. The greater portion of 

the residue was removed with a spatula and the firmly adhering 

portion was removed by vigorous scouring with emery cloth, a fresh 

piece of cloth being used for each residue.

TESTING OF SOLIDS.

In determining the radium content of the spring deposits, water 

residues, and rock samples the method devised by Stmtt ° in his investigations on the distribution of radium in the crust of the earth was 

followed in the main.

The calcareous deposits were dissolved in hydrochloric acid and 

the solution stored for several weeks in tightly corked flasks. The 

weights of material used in these determinations are given in the 

tabulated statement of results which appears further on. The slight 

quantities of insoluble residue were not removed, but were stored 

with the solutions. After the requisite period of storage the accumulated emanation was boiled off in an apparatus similar to the one 

used in the tests with water samples, except that the flask in which 

the solution was stored served as the boiler. The quantity of emaoProc. Roy. Soc., vol. 77, 1906, p. 472..

88865 Bull. 395 09 2
18 RADIOACTIVITY OF THERMAL WATERS

nation was then determined, as it was for water and gas samples, by 

means of a standardized -electroscope. With the siliceous deposits 

and the rock samples the determination of radium in small quantities 

involves more labor. The sample must first be ground to go through 

a 100-mesh sieve. Then it is .fused with a mixture of alkali carbonates, the mass extracted with water, and the soluble portion stored 

in a tightly corked flask. The residue after it is dissolved in hydrochloric acid is stored in another flask. The activity of the two solutions is determined at the end of three or four weeks, as before 

described in connection with the water tests. From the data thus 

obtained the quantity of radium per gram of substance is readily calculated.

RESULTS OF THE EXPERIMENTS. 

GENERAL STATEMENT.

The experimental results of this investigation are presented in five 

tables, showing the radioactivity of gases, waters, water residues, 

spring deposits, and rock samples. Finally, the results for the activity 

of gases, waters, and deposits are summarized for better comparison 

in an additional table.

EXAMPLE SHOWING METHOD.

The data obtained in the test of White Sulphur Spring at the Lower 

Geyser basin are'summarized here to illustrate the procedure followed 

and to show the method of calculation of the values given for radioactivity in the tables. The test was conducted August 1, 1906. The» 

temperature of the water in the pool at the. point where samples were 

collected was 59° C., and the water was slightly alkaline to litmus 

paper. The gas escaping from two orifices under the water at the 

SOllth end of the pool were first tested qualitatively for thorium and 

radium emanation by the use of the apparatus shown in figure 3. As 

the gas issued relatively slowly, ten minutes was consumed in passing 

the accumulating gases along the circuit through electroscope No. 1. 

About 1,100 cubic centimeters of gas was transmitted, as measured 

by 15 squeezes of the hand bellows. The first readings of the fall 

of the charged leaf were taken thirty seconds after the gas delivery 

was stopped. ' In this case no decrease in activity was observed during 

the first two minutes of observation. Hence thorium emanation was 

absent. In the course of ten minutes the leak increased about 12 per 

cent, which is characteristic of radium emanation. The gas evidently 

was relatively rich in emanation, as the leak was fully 1,000 times 

the usual air leak of the instrument. Our field journal shows that 60 

small divisions of the scale were passed over by the leaf in eleven and 

six-tenths seconds. After twelve minutes of observation the gas was 

blown out and the electroscope set aside for a time to wait for the
U. 8. GEOLOGICAL SURVEY 

NORR1S GEYSER BASIN.
OF YELLOWSTONE NATIONAL PARK. 19

decay of the induced activity. Later in the day a quantitative determination of the radium emanation present in the escaping gas was 

made with the same electroscope. Ninety cubic centimeters of gas 

were collected over water (temperature 40°C.) and introduced into the 

partially exhausted electroscope. At maximum activity the leaf fell 

23.6 small scale divisions per minute after deducting the normal air 

leak, which was 0.2 division per minute. The volume of the gas sample 

reduced to normal temperature and pressure is 56.3 cubic centimeters.'1 In this electroscope a leak of one division per minute represented 2.8 X 10~4 grams uranium or 10.64 X 10~n grams radium. The 

activity of the gas per liter, in terms of the uranium standard, is hence 

expressed by the following equation:

23.6X2.8X10-4 X1,000 117vU)-, 56.3 -li/Xiu .

Expressed in terms of the radium standard the activity equals

The value of the ionization current per liter of gas, in electrostatic 

units, is obtained by substituting in the formula:

j_ qXcXl,QOO 

300XtX56.3'

For q may be put the potential fall in volts during the interval of 

time (t) expressed in seconds, and c is the electric capacity of the 

electroscope. Since each division of the scale represents 1.24 volts, 

and the capacity is 2.81 centimeters, the numerical equation for the 

value of the ionization current is:

?MX1.24X2_81_XliOOO = 8L2xlo.3 electrostatic units. 

oOl)XoOX5o.o

For the .determination of the activity of the water from this spring, 

the water gas separated from a sample of 2,570 cubic centimeters was. 

introduced into electroscope No. 2. This sample of water was collected in the immediate vicinity of the orifices from which the gas 

issued. The maximum net leak observed was 10.9 scale divisions 

per minute. The activity of the water sample, per liter, in terms of 

the uranium standard, is given by the equation:

10.9X7.7X10-"

2.57

= 32.6X10~4 .

This value is equivalent to 1,238 X 10~12 grams radium. The numerical equation for the ionization current in electrostatic units has* the

form:

10.9X2.80X3.51

300X60X2.57

= 2.33X10-3 .

a Iii reducing the observed gas volumes to those for normal conditions the value 600 millimeters was used 

for the barometric pressure in all the calculations. Correction was of course made for the aqueous tension.
20 RADIOACTIVITY OF THERMAL WATERS

The water sample upon evaporation left a residue weighing less 

than 2 grams. Its radium content was too small to be determined 

in so small a quantity of material. It therefore follows that the 

activity of the water is temporary in nature, and that the dissolved 

radium, emanation did not come directly from the radium salts carried in solution. The greater portion of the emanation doubtless 

diffused into the water from the radium-bearing rocks with which 

the water came in contact in the course of its underground flow.

RADIOACTIVITY OF GASES.

The names of the gas sources in Table 2 are those found in the 

atlas accompanying Monograph 32 of the United States Geological 

Survey, entitled "Geology of Yellowstone Park." The locality 

names in the second column of the table are also the official names. 

Names inclosed in quotation marks are not official. The third column shows whether thorium emanation was detected in the qualitative field test. In some instances the activity due to thorium is compared with that observed for radium. In the last column the activity 

values are recorded in both the uranium and the radium standards. 

They represent the radium emanation present per liter of gas. The 

blank spaces indicate that no test was conducted.

TABLE 2. Radioactivity of gases in Yellowstone Park.

MAMMOTH HOT SPRINGS.

Name of source.

Bath Lake. . .............................

Location.

.....do.. .....................

.....do.......................

.....do.. .....................

.....do.......................

Thorium 

emanation.

None. 

None. 

None. 

. None. 

None. 

None. 

None.

Radium emanation.

Uranium 

(grams X10-3).

 1.5 

7.5 

Trace. 

Trace. 

None. 

None. 

None. 

None.

Radium 

(grams XlO-s).

0.57 

2.85

NORRIS GEYSER BASIN.

Pool..................................... Near Sky Rocket Geyser. . . .

None. 

None. 

7.5XRa. 

Present.

(?) 

2XRa. 

Trace. 

Present.

>39.6 

>18.0 

>52 

Pres 

Pres 

>13 

> 9 

Pres 

67.7

ent. 

ent.

ent.

15.0 

6.8 

19.8

4.9 

3.4

25.7
OF YELLOWSTONE NATIONAL PARK. 21

TABLE 2. Radioactivity of gases in Yellowstone Park Continued. 

LOWER GEYSER BASIN AND TERRACE SPRINGS.

Name of source.

White Sulphur Spring (1 )................

White Sulphur Spring (2). ...............

Mammoth Paint Pots (1)6.... . ...........

Mammoth Paint Pots (3)&. ...............

Location.

.....do.......................

.....do.......................

Near and northwest of Clepsytra Geyser.

.....do.......................

.....do.......................

.....do.......................

.....do.......................

.....do.......................

.....do.......................

Thorium 

emanation.

None. 

ISXRa. 

3XRa. 

None.

None. 

None. 

None. 

Trace. 

None. 

None. 

None. 

Trace.

$ None.

None. 

None. 

None. 

None.

Radium emanation.

Uranium 

(grams X10-3).

> 6

> 13 

> 11

1,200

No 

Tn 

Tn 

40.7 

117 

69 

" No 

Tn 

Tn 

864 

478 

TK 

750 

492

Radium 

(grams XlO-o).

2.3 

4.9 

4.1 

45C

ne. 

ice. 

ice. 

15.5 

44.5 

20'.2 

ne. 

ice. 

ce. 

329 

182 

ice. 

287 

187

UPPER GEYSER BASIN.

Pool.....................................

Old Faithful Geyser......................

.....do......................

Across road from Castle Geyser.

.....do.......................

.....do.......................

.....do.......................

.....do.......................

.....do.......................

None. 

 Trace. 

None. 

None. 

None. 

None. 

None. 

None. 

None. 

None. 

None.

None. 

None. 

None. 

None. 

None. 

None. 

None. 

None. 

None.

122 

Yes. 

843 

300 

No 

No 

Tn 

No 

508 

 Tn 

514

Tn 

1,218 

No 

Pres 

206 

509 

416 

No 

416

40.3

321 139 ' 

ne. 

ne. 

ice. 

ne. 

193 

ice. 

196

ice. 

462 

ne. 

ent. 

78 

194 

158 

no. 

158

SHOSHONE GEYSER BASIN.

None. 

None. 

None. 

None. 

None. 

None. 

None.

>750 

861 

>600 

Tn 

896 

> 30 

> 50

285 

328 

228 ice. 

340 

11 

19

HEART LAKE, GEYSER BASIN.

South of Rustic Geyser......

Heart Crater, Factory Hill. .

None. 

None. 

None. 

2XRa.

>700 

939 

59 

243

266 

356 

19 

92

a Terrace Spring No. 1 is the lowest one on the terraces. It discharges large quantities of gas; No. 3 is on 

the third terrace; the volume of gas discharged from Nos. 2 and 3 is relatively small; less gas escapes from 

No. 2 than No. 3. 

t> Test 1 on the west side of the group; No. 2 on the south side, and No. 3 on the east side.
22 RADIOACTIVITY OF THERMAL WATERS

TABLE 2. Radioactivity of gases in Yellowstone Park Continued.

WEST THUMB, YELLOWSTONE LAKE.

Name of source.

Paint Pot. ...............................

Location.

One mile from military post. 

.....do......................

Thorium 

emanation.

None. 

None. 

None. 

Present. 

/Equal to 

\ Ra. 

None.

Radium, emanaton.

Uranium 

(grams X10-3).

382 

45 

266 

>150

} 309 

123

Radium 

(grams X10-9 ).

145 

17 

107 

51

117

47

LOCALITIES ALONG YELLOWSTONE RIVER.

Pool................ .....................

Pool................ .....................

Black Pool (1) ...........................

Black Pool (2). ..........................

South area of activity, mud 

geysers. 

East of large mud geyser. . . .

.....do.......................

West side of formation, 

Mount Washburn. 

Mount Washburn....... . .

Tower Falls. ................

. None.

None. 

None. 

None. 

4XRa. 

Present. 

Present.

(?) 

(?)

49

155 

7.6 

TK 

>110 

> 40 

> 50

17.2 

19.2

18.0

59 

2.9 

ice. 

42 

15 

19

0.5 

7.3

RADIOACTIVITY OF WATERS.

The values. recorded for the activities of the water samples in 

Table 3 are expressed in terms of both the uranium and the radium 

standards. They represent the radium emanation in a fresh sample 

of water. In several instances some time elapsed between the collection of the sample and the determination. In such tests correction 

was made for the decay in the activity of the samples during the 

interval between the time of collecting and the time of testing by 

means of the formula I0 = Ite~rt, expressing the decay of activity with 

the time. I0 represents the initial activity, It the activity observed 

t hours after the water was collected, and r the radioactive constant 

of radium emanation. The value of r used in the calculations was 

0.0077, which is an approximate mean of the values found by several 

investigators. The temperatures given were taken with a normal 

centigrade thermometer graduated in degrees. The instrument was 

not self-registering. At some of the springs it was difficult to get 

accurate readings, as the hot water and vapors interfered materially 

with readings at close range. For the most part the values recorded 

are correct to within half a degree. As the reaction of the waters to 

litmus paper was tested, the results are recorded in a separate column. 

This table, like the preceding one, is subdivided on the basis of the 

more important localities. Several of the names recorded are not 

found on the maps of the United States Geological Survey. Most of
OF YELLOWSTONE NATIONAL PARK. 23

these, however, are probably the official names, as they appear on 

the printed signboards. New names are inclosed with quotation 

marks. We aimed to include the spring waters of the park analyzed 

by Gooch and Whitfield.0

TABLE 3. Radioactivity of waters in Yellowstone Park. 

MAMMOTH HOT SPRINGS.

Name of source.

Hot River (la)&. ..........

Hot River (lb)&... ........

Hot River (2)6............

Diana Spring. .............

Cold Spring. ..............

Soda Spring. ..............

Location.

1 mile north of fort. . ....

.....do..................

.....do..................

Hymen terrace..........

Foot of Minerva terrace. 

Minerva terrace .........

.....do..................

.....do..................

.....do..................

.....do..................

% mile south of fort on 

old road to Golden 

Gate. 

Summit Lake. .......... 

10 miles south of Mammoth Hot Springs.

Temperature.

°C. 

11 

51 

51

71 

71 

70.5

70 

71 

70 

32 

46 

39 

63.5 

10.5.

15.5 

9.2

Reaction, etc.

.....do............

.....do............

.....do............

.....do............

.....do............ 

.....do............

.....do............ 

.....do............ 

.....do............ 

.....do............

.....do............

.....do............ 

Acid..............

Slightly acid......

Activity.

gxio-<u.

No 

42.3 

37.9 

29.3 

Tr 

No 

No 

No 

No 

No 

No 

1.85 

Trac 

' 5.27

No 

7.3

3.2 

31.9

gxio-"

Ra.

ne. 

161 

144 

111 

ace. (?) 

ne. 

ne. 

ne. 

ne. 

ne. 

ne. 

7

B.(?)

20 

ne. 

27.7

12.2 

121

NORR1S GEYSER BASIN.

Gibbon River... :.........

Realgar Spring. ........... 

The reservoir ..............

"Black Sulphur" Spring..

Pool near Constant Geyser.

Locomotive ...............

Primrose Spring. ..........

A cold spring. .............

A carbonated spring. ......

5 miles north of Norris. . .

Near Iron' Spring and 1 

mile north of post on 

trail. 

1 mile east of Norris on 

road to canyon.

1 mile up G ibbon River. . 

In meadow across river 

from army post.

100-spring plain ......... 

.....do..................

300 feet west of hotel ....

.....do..................

.....do..................

Near Nuphar Lake. ..... 

Near Primrose Spring. . . 

6t miles south of Norris, 

"by roadside. 

8 miles south of Norris, 

by roadside.

85 

15 

50.5

16

75

.....7.... 

90 

58 

67 

51 

89 

82 

88 

89

(<0

Faintly alkaline...

"Slightly acid '.'.'.'.'..

Slightly acid...... 

Strongly acid..... 

Slightly acid...... 

.....do............ 

Strongly acid.....

Strongly acid .....

0.34 

13.1 

1.9

17.5

No 

33.5 

20.0

18.7 

10.6 

6.9 

4.6 

1.1 

1.23 

7.0 

1.15 

1.2 

1.0 

0.5 

2.05

9.0

1.3 

49.7 

77.2

66.5

le. 

128 

76

71 

40.5 

26.5 

17.4 

4.2 

4.6 

26.6 

4.4 

4. 55 

3.8 

1.9 

7.8

34

« Bull. U. S. Geol. Survey No. 47.1888.

* Samples la and Ib were collected where the main current of Hot River first issues from the rock. Test 

la was made July 15,1906; Ib. the following day. Sample 2 was taken from a small hot stream that empties 

into Gardiner River about 60 rods upstream from the mouth of Hot River.

cCold.
24 RADIOACTIVITY OF THERMAL WATERS

TABLE 3. Radioactivity of waters in Yellowstone Park Continued.

LOWER GEYSER BASIN.

Name of source.

White Sulphur Spring.....

Pool.......................

Location.

4 miles north of Fountain hotel' near roadside.

Near Clepsytra Geyser. .

Near Great Fountain 

Geyser. . East of road, Excelsior 

basin.

Temperature.

"C.

63 

40 

53 

88 

85 

59

85 

75

65 

92

Reaction, etc.

Slightly alkaline...

.....do............

.....do............

.....do............

.....do............

.....do............

.....do............

Slightly alkaline...

Activity.

gxio-<u.

8.2

5.3 

2.4 

Tra 

No 

16.3 

32.6 

8.5 

10

34.7 

Tn

gX 10-n 

Ra.

31

20 

9.1 

ce. 

ne. 

62 

124 

32 

38

131 

,ce.

UPPER GEYSER BASIN.

Firehole River............

Hot Spring................

Do....................

Spring....................

A mountainside spring-. . . .

Near army post. ........ 

Near Gem Gevser

Near Solitary Spring. . . .

Near Economic Geyser..

Water supply for Old 

Faithful inn. 

3 miles up Spring Creek.

61 

19 

64 

86 

86 

52 88 - 

81 

82 

70 

82 

13 

31

10.5

.....do............

Faintly alkaline...

.....do............

Faintly alkaline... 

.....do............

.....do............

6.5 

Tre 

70.5 

6.4 

8. 45 

26. 5

No 

23.9 

6.1 

8.1 

4.8 

67. 5 

11.2

14.9

25 

ice. 

268 

24 

32- 

101 

ne. 

91 

23 

31 

18 

 256 

42.5

56.5

SHOSHONE GEYSER BASIN.

Acid..............

"j 9

40.9

22.,

155

HEART LAKE GEYSER BASIN.

Near Rustic Ge 'ser 19.1

4.7

72.5

17.8

WEST THUMB, YELLOWSTONE LAKE.

Pool....................... Near Paint Pots ........

.....do............

Acid..............

37. 5

1.2

1.4

22.6

16.8

142

4.6

5.3

86

64

YELLOWSTONE RIVER LOCALITIES.

Do............ ........

N vmnh Snrine ............

Camp Howard.. ......1-----.----

Mud Geysers; south 

basin of activity.

Sulphur Mountain ...... 

Foot of lower falls, canyon.

Dunraven Pass. Mount 

Washburn.

.....do..................

Tower Falls............

88

Neutral...........

Acid.............. 

.....do............

.....do............

Acid..............

.....do............

Neutral...........

No 

15.1

54.6 

No 

3.0

6.35 

10.3

.6 

1.35 

. 6.9

ne.

57

207 

ne. 

11.4

24.2 

39

2.3

 5.2 

26.3

a Sample was collected 5 minutes after the geyser played.
OF YELLOWSTONE NATIONAL PARK. 25

RADIOACTIVITY OF WATER RESIDUES, SPRING DEPOSITS, AND ROCK

SAMPLES.

The values given for the activities of solids in Tables 4, 5, and 6, 

represent the radium present per gram of the air-dry material. The 

quantity of material taken in each determination is recorded in the 

third column of the tables. The samples in Table 4 are water residues; 

those in Table 5 are incrustations deposited by the springs where the 

water issues. The samples were collected for the most part at the 

time the water samples were tested, and the radium was determined 

during the }^ears 1906 and 1907. Several samples of travertine at 

Mammoth Hot Springs were collected by Capt. William II. Forsythe, 

U. S.' Army.' Some of the rock samples from typical formations in 

the park were obtained from the collection of the United States 

Geological Survey through the kindness of Dr. Arnold Hague.

TABLE 4. Radioactivity of water residues, Yellowstone Park.

Name of source. Locality.

.....do..................................

Springs.

Weight 

of sample 

(grams).

4

4

4.2

4

2.5

Radium 

per gram 

(gramX 10-' 2 ).

4.33

5.4

2.81

TABLE 5. Radioactivity of spring deposits, Yelloivstone Park. 

MAMMOTH HOT SPRINGS.

" Name of source.

Hot River (la) ...........................

Hot River (2)o. ..........................

Main Spring (2)...........................

Hymen Spring ..........................

Liberty Cap (a) ...........................

Liberty Cap ( b;. ..........................

Cleopatra Spring. .........................

Old Travertine. ..........................

Do......................:............

Locality.

.....do...................................

Weight 

of sample 

(grams).

38

100

inn

54

38

85

59

58 '82

100

Radium 

per gram 

(gramX 

10-n).

9.12

8.28

Q 7A

11.2

4 Q

1 96

1 QA

15.24

 4. 26

3.76

.08

Paint Pot. ...............................

Black Sulphur Spring. ...................

Paint Pot (Artists). . ...............

Of,

30

30

25

sn

sn

30 50

2 25

111

ql

1.60

9 3Q

1.40

EQ

3 ^7

<* Sample la is from main stream; No. 2 is from small outlet.
TABLE 5. Radioactivity of spring deposits, Yellowstone Park Continued. 

LOWER GEYSER BASIN.

Name of source. Locality.

Weight 

of sample 

(grams').

Radium

per gram

(gramX ID-").

Terrace Spring No. 2...................... Terrace Springs......................... 25 1.87

White Sulphur Spring.............................................................. 25 .49

Pool and spring........................... Near Clepsytra Geyser.................. 50 .11

Mud volcano............................. Near Rush Lake........................ 50 G. 4

Firehole Lake (1)................... ............................................... 50 7.5

Firehole Lake (2)......................... .......................................... 40 G. 9

UPPER GEYSER BASIN.

Asta Spring.............................. Hillside Springs......................... 30 3.15

Bench Spring............................. ......................;................... 30 l.OG

Splendid Geyser.................................................................... 30

Giant Geyser....................................................................... 25 .47

SHOSHONE GEYSER BASIN.

" Sulphur" Spring.................................................................. 30 1.30

Wave Spring....................................................................... 30 0.40

HEART LAKE GEYSER BASIN.

"Hillside" Spring........................ Near Rustic Geyser..................... 30 1.41

"Orange" Spring....................;.... Head of basin........................... 30 1.83

WEST THUMB, YELLOWSTONE LAKE.

Paint Pot (a)............................. .......................................... 50 2.32

Paint Pot (b)............................. .......................................... 25 2.51

Fish Cone.......................................................................... 50 0.21

YELLOWSTONE RIVER LOCALITIES.

Mud Geyser.............................. .......................................... 25 0.07

Devil'slnkPot........................... Mount Washburn....................... 73.4 0.34

Forest Springs............................ Yellowstone Canyon.................... 25 1.45

TABLE 6. Radioactivity in rock samples, Yellowstone Park.

Name of sample. Locality. Weight 

in grams.

Radium

per gram

(gram X

lO'12).

Rhyolite(a)................

Rhyolite (b)................

Obsidian...................

Obsidian...................

Lava.......................

Petrified tree...............

Oolitic limestone...........

Rhyolite, specimen No. 504. 

Rhyolite, specimen No. 603.

Golden Gate, Mammoth Hot Springs, 

.do.

Obsidian Cliff...................

Madison Plateau................

Lava Creek.....................

Near Yanceys..................

Near Mammoth Hot Springs. 

Gibbon Canyon.................

Hot Lake, Lower Geyser basin.

25

25

50

25

50

70

240

55

56

1.51

1.7

2.32

1.57

0.46

0.065

2.9

2.84

3.24
OP YELLOWSTONE NATIONAL PARK. 27

SUMMARY OF RADIOACTIVITIES.

To facilitate comparisons, most of the results presented in the foregoing tables are summarized in Table 7. The values are expressed 

in terms of the radium standard.

TABLE 7. Summary of radioactivities of gases, waters, and deposits in Yellowstone Park.

MAMMOTH HOT SPRINGS. ^

Name of source.

Cleopatra Spring. . .................................

Hot River (la) ....................................

Date of 

field test, 

1900.

July 14

July 15

July 16

July 10

July 17

July 18

July 16

July 17

July 18

July 18

Radium per 

liter of gas 

(gramX10-»).

None.

None.

None.

Trace.

Trace.

6.57

2.85

Radium per 

liter of water 

(gramxiO-").

None.

None.

Trace.

Trace.

None.

161

ill

12.2

7.0

Radium per 

gram of deposit (gram XlO-»).

9.9

15.24

4.3

9.12

8.28

NORRIS GEYSER BASIN.

July 23

July 25 

July 24 

July 20 

July 27 

July 28

>15 

> 6.8 

>19. 8 

> 4.9

25.7

4.4 

17.4 

4.2

3.8

1. 15 

1.4 

0.31 

2.25 

1.0 

0.59

LOWER GEYSER BASIN.

Pool ClcT)svtr£i Gcvsor

White Sulphur Spring. ............................

Aug. 1 

Aug. 1 

July 30 

July 31 

Aug. T 

Aug. 3 

Aug. 3 

Aug. 5 

Aug. 5

>4.9 

>2.3 

None. 

450 

44.5 

329 

182 

287 

187

9.1 

20 

None. 

62 

138 

32

38 

131

1.87

0.11 

0.49

7.5 

0.9

UPPER GEYSER BASIN.

Old Faithful....... ................................

Aug. 11

Aug. 11

Aug. 11

Aug. 12

Aug. 8

AllfT Q

An or Q

Aug. 7

40.3

321

139

193

462

158

25

268

24

32

91

23

18

1.06

3.15

0.08

0.47

SHOSHONE GEYSER BASIN.

Wave Spring.......

Three Crater Spring. 

A sulphur spring....

Aug. 13 

Aug. 13 

Aug. 14

>285 

328 

340

22.5

155

0.46 "i.'s'o

HEART LAKE GEYSER BASIN.

Aug. 21

Aug. 22

>266

92

72.5

17.8

1.42

1.83
RADIOACTIVITY OF THERMAL WATERS

TABLE 7. Summary of radioactivities of gases, waters, and deposits in Yellowstone

Park Continued.

WEST THUMB, YELLOWSTONE LAKE.

Name of source.

Paint Pot. .........................................

Date of 

field test, 

1906.

Aug. 17

Aug. 17

Aug. 18

Aug. 17

Aug. 18

Radium per 

liter of gas 

(gramXIO 9).

145

17

>57

47

101

117

Radium per 

literofwater 

(gramXIO").

72.5

4.6

5.3

04

Radium per 

gram of deposit (gram 

X10-12).

2.32

0.21

YELLOWSTONE RIVER LOCALITIES.

Devil's Ink Pot. ...................................

Aug. 28

Sept. 5

18. C

59

15

7.3

57

107

24.2

2.3

26.3

0.07

1.45

0.34

DISCUSSION OF RESULTS. 

GAS ACTIVITIES.

Thorium emanation. The tabulated results show that marked 

differences exist in the activity of gases from different springs. In 

most cases the activity is due entirely to radium emanation. In at 

least 16 of the 82 gas sources examined thorium emanation was found 

associated with that of radium. These are the first springs on this 

Continent which to our knowledge have been found to contain thorium 

emanation, and the number reported in Europe is small. The 

initial activity due to thorium emanation varied from a mere trace to 

fifteen times that due to radium emanation in the same gas. Owing to 

the rapid rate of decay of the thorium emanation the results relative 

to it are only approximately quantitative and represent- the minimum quantity. The thorium emanation was most marked at Norris 

Geyser basin and at Terrace Springs near the mouth of Gibbon River. 

Thorium emanation was not found alone in any gas. Some radium 

emanation always accompanied it. Actinium emanation was looked 

for, but without success. Its extremely rapid rate of decay (half 

value in four seconds) makes its detection difficult in small amounts 

under field conditions.

Relative activity. In only one of the ten localities visited, in the 

park were the escaping gases found, on the whole practically inactive. This locality is the well-known group of springs in the northern 

part of the park, known as Mammoth Hot Springs. Since the volume of the escaping gases from these highly carbonated waters is 

relatively large, this fact probably accounts for the extremely low 

concentration of the emanation in the gases and waters of this locality. 

In this connection it should be mentioned that the most active gas 

recorded (pool near Model Geyser, Upper Geyser basin) issued very
U. S. GEOLOGICAL SURVEY

A. OLD FAITHFUL GEYSER, UPPER GEYSER BASIN.

B. HOT SPRING, NORRIS GEYSER BASIN, WHERE THORIUM WAS FIRST DISCOVERED IN THE

UNITED STATES. . .. - ,
OF YELLOWSTONE NATIONAL PAEK. 29

slowly, and that the next most active gas (pool near Clepsytra Geyser, 

Lower Geyser basin) required nearly an hour for the collection of a 

sample of 50 cubic centimeters in a bottle having a mouth 3 centimeters wide. The latter spring gives the appearance of discharging 

gas freely, but most of the bubbles proved to be steam.

Gases from European springs. Some of the well-known thermal 

and cold springs on the European Continent are more or less charged 

with gases, like many of those of Yellowstone Park. The radioactive 

properties of the gases escaping from the European springs have been 

extensively studied by different investigators, and numerous quantitative results are thus available for comparison. The following table 

gives representative data for -gases from springs in various European localities and for different localities in Yellowstone Park. The 

values for the activity in the third column of the table are expressed

in electrostatic units.

TABLE 8. Radioactivity of gases from springs in Europe and in Yellowstone JJark.

Name of source.

Wolrl Qnpllp

Nymph Spring. ......................

Location.

.....do.......................

.....do.......................

.....do.......................

.....do...... ................

.....do.......................

VipVi v

.....do.......................

Lake. 

Tower Palls.. ...............

Activity 

(electrostatic units, 

I X 103).

504

412

94.2

50.2

1.51

10.9

1.48

21.9

2.18

2.60

16.6

184

23

18

1 9 1;

50

47 finn

834

254

353 ws

85

13.3

Observer.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

a Sitzungsber. K. Akad. Wiss., Wien, Abt. 2a, vol. 113, p. 1329. 

6 Idem, vol. 114, p. 355. 

c Idem, vol. 114, p. 545. 

d Compt. Rend., vol. 138, p. 1150 

 « Jahrbuch Radioak., vol. 2, p. 77. 

/Sitzungsber; K. Akad. Wiss., Wien, Abt. 2a, vol. 113, p. 1092.

Although the values for the activity as given by different observers 

are based upon somewhat "different systems of reckoning (some investigators, Maclie, for example, do not include the ionization effect of 

the disintegration products), still the values given show that the 

ga-ses from the springs in Yellowstone Park are fully as active as those 

from European sources.

Helium not determined. In several of the more active European 

springs it is known that helium is one of the constituents of the 

escaping gas. No tests were made by us to ascertain the presence of
30 EADIOACTIVITY OF THERMAL AVATEES

helium in any of the gases tested. The marked radioactive properties of the gases from many of the springs would make an examination 

of the gases for helium and the other rare gases very desirable.

ACTIVITY OF WATERS.

Inferences from different results. The tabulated results clearly show 

that the thermal waters in different localities and even in the same 

locality differ considerably in activity. In some samples no activity 

was detected. Several cold springs were also tested. These likewise 

showed marked differences in activity, and their average somewhat 

exceeds that of the thermal springs. It is evident then that the. temperature of the waters is independent of their activity. Similar variations in activity were found by Boltwood" in his extensive tests of 

the radioactive properties of the waters of Hot Springs, Ark., and by 

us in connection with the examination of some natural waters of 

Missouri. 6 The acidity or alkalinity of the water seems to have no 

connection with its activity.

Is the activity of the waters due to radium emanation which has 

diffused into them in the course of their underground flow, or is it 

produced by the radium that the waters carry in solution ? As those 

water residues which were examined yielded only traces of radium 

emanation, we may conclude that the radium salts in solution are 

responsible for only a small part of the total activity, most of which 

is due to radioactive gases that have diffused into the waters.

Some of th« differences observed in the activities are readily explained. The water of boiling springs and therefore of geysers almost 

invariably gave negative tests. Such a temperature is not favorable 

for the retention of dissolved gases. The escaping steam and the 

consequent agitation of the waters are both effective in removing any 

radioactive gases that may have been absorbed by the water.

The same effect may be caused in another way. If a large volume 

of gas is evolved from a spring, whose temperature may lie considerably below the boiling point, the emanation is swept out of the 

water by the gas. Such a condition also is not favorable for the 

accumulation of radioactive gases. In such a spring the activity of 

the gas also will prove to be low, although a considerable amount of 

emanation may have been removed by it.. If these conditions were 

not considered such a spring might be classified as inactive, though 

its residue on evaporation might be found to contain appreciable 

quantities of radium. Most of the springs tested at Mammoth Hot 

Springs are examples of this condition. All of the springs on the 

Main Terrace gave negative results for both waters and gases, within 

the limits of error of our instruments under field conditions, and yet 

the residues and deposits, as Tables 4 and 5 show, greatly exceed in

a. Am. Jour. Sci., vol. 20, 1905, p. 128.

6 Trans. Am. Eleetrochem. Soc., vol. 8,1905, p. 291.
OF YELLOWSTONE NATIONAL PAEK. 31

activity those of springs in other localities, the waters of which were 

found to be radioactive in a marked degree.

At all events the results for waters and gases show that the underlying rock in the park contains radium and in some localities thorium in sufficient quantities to make the waters and gases decidedly 

radioactive.

Comparison with European waters. The radioactive properties of 

European thermal and mineral waters have been studied extensively 

by different investigators. From the numerous quantitative data a 

few have been selected and arranged in tabular form. Some of the 

values obtained by Boltwood in his examination of the waters of Hot 

Springs, Ark., are incorporated in the table, as well as values obtained 

for some Yellowstone Park waters.

TABLE 9. Radioactivity of spring waters in Europe and in the United States.

Name of source.

Crabenb ticker Quelle. . . .

WaldQuelle.. ..:........

Quelle am Schweizergang

Kaiser Friedrich Quelle. .

Hot River. ..............

Apollinaris Spring. ......

Firehole Lake. ..........

Three Crater Spring... . . .

Locution.

.....do................

Karlsbad..............

.....do................

.....do................

.....do................

.....do................

St. Joachimsthal. .....

Odenwald, Hessen. . . .

Bad Kissingen........

.....do................

.....do................

.....do................

.....do...............

.....do..........;.....

Sweet Springs, Mo ....

Mammoth Hot 

Springs. 

South of Mammoth 

Hot Springs. 

Norris basin...........

Lower Geyser basin. . 

Upper Geyser basin . . Near Economic Geyser

Tower Falls...........

Temperature.

°C. 

36.3 

46.8 

39.2 

30.2 

44.6 

7.0 

7.8 

45.9

18.5 

23.3 

30.0 

14.2

10.3

19.5 

9.6

60.8

62.4

56.4

8.0

57.8

57.2

. Cold. 

51 

9.2

Thermal. 

85 

86 

81

Activity.

Electrostatic units

0X103).

155 

133 

31.5 

17.4 

3.11 

4.57 

1.62 

4.96

0.56 

0.71 

4.54

185 

9.4

10.5 

0.7

12.5

1.1 

13.0 

2.86 

2.3

26.3 

22.1

7.4 

5.9 

4.44 

16.6 

4.1 

4.8

Uranium 

(grams

x io-«).

266 

65.4 

23.9 

17.4 

7.7 

3.7 

23.7

37.9 

 31.9

10.6 

8.5 

6.4 

23.9 

5.9 

. 6.9

Observer.

Mache. <* 

Do. 

Mache and Meyer.6 

Do. 

Do. 

' Do. 

Do. 

Do. Do.c 

Do. 

Do. 

Do. 

Curie and La- borde.d 

Do. 

Do. 

Borne. « 

Schmidt and 

Kurz /. 

Do. 

Do. 

Jentzsch.0 Henrich.ft 

Boltwood. i 

Do. 

Do. 

Do. 

Do. 

Do. 

Moore and 

SchlundtJ 

S c h 1 u n d t and 

Moore. 

Do.

Do. 

Do. 

Do. 

Do. 

Do. 

Do.

a Sitzungsber. K. Akad. Wiss., Wien, Abt. 2a, vol. 113, p. 1329.

6 Idem, vol. 114, p. 355.

cldem, vol. 114, p. 545.

dCornpt. Rend., vol. 142, 1906, p. 1462.

« Jahrbuch Radioak, vol. 2, p. 77.

/Phys. Zeitschr., vol. 7, 1900, p. 214.

ff Idem, vol. 8, 1907, p. 887. 

A Sitzungsber. K. Akad. Wiss., Wien, Abt. 2a, vol. 113, p. 1092.

»Am. Jour. Sci., vol. 20, 1905, p. 128.

;' Trans. Am. Electrochem. Soc., vol. 8, p. 291.
32 . EADIOACTIVITY OF THERMAL WATERS

A comparison of the activities of the thermal waters of Yellowstone Park with those of European springs, as given by the foregoing 

table, shows that with a few exceptions the quantity of radium 

emanation carried is of the same order of magnitude and that marked 

variations exist. It is seen that the European springs in localities 

where deposits of pitchblende occur are distinctly more radioactive. 

In making comparisons of this kind, however, it must be borne in 

mind that the temperature of most of the park waters is near the 

boiling point, and that this factor is unfavorable for the accumulation of the emanation. It is worthy of note, in this connection, that 

the gases escaping from many, of the springs in the park contain about 

the same quantity of radium emanation as the most active European 

thermal springs, which are located in regions where extensive deposits 

of radioactive minerals occur. It is therefore probable that many of 

the park waters traverse radium-bearing minerals in the course of 

their underground flow.

The waters of Hot Springs, Ark., are probably fully as active as 

those of the park, but their temperatures average considerably lower. 

The gases rising from two of the springs at Hot Springs were found by 

Boltwood a to be less active than equal volumes of gases separated 

from the waters by boiling, a result in direct contrast with our observations on the thermal springs of the park.

A discussion of the results in the foregoing table with respect to the 

hydrography of the different localities lies beyond the scope of this 

paper.

RADIUM CONTENT OF DEPOSITS AND ROCKS.

Comparative activity of different rocks. At Mammoth Hot Springs 

the waters are calcareous, the dissolved material being derived from 

the underlying Jurassic and Cretaceous. At the other basins the

waters are siliceous (some alkaline, some acid), the dissolved material 

being derived from the rhyolite of which the park plateau is largely 

formed. In both classes of deposits radium was detected.

The deposits of travertine at Mammoth Hot Springs contain radium 

in appreciable quantities. The activity of the residue obtained by 

evaporating the water is about half that of the deposits, showing that 

the radioactive material is largely deposited with the components that 

come out of solution first. This fact alone would account in a large 

measure for moderate differences in the radium content of the deposits 

formed by different springs of similar origin. The values obtained at 

Mammoth Hot Springs for the radium content of the deposits from the 

actively flowing springs, however, are of the same Order of magnitude. 

The radium content of these deposits averages about 8X1CT12 grams 

per gram of material, a value two and one-half times greater than the

a Am. Jour. Sci., vol. 20,1905, p. 128.
MORNING GLORY POOL, UPPER GEYSER BASIN
OF YELLOWSTONE NATIONAL PARK. 33

radium content of the rock from which the deposits are probably 

derived, and about five times the average radium content of the 

igneous rock of the park. To account for the concentration of radium 

in these spring deposits more experimental work is necessary. An 

investigation of the solvent action of hot, carbonated water on radiumbearing rock samples at different pressures might throw some light on 

the question. Again, the fact that radium in the Mammoth HotSpring deposits is largely deposited 'with the components that first 

come out of solution may be connected with the numerous growths of 

alg£e in these hot waters, which may act as precipitating reagents.

The siliceous deposits from some of the springs in the other basins; 

of thermal activity likewise show a higher radium content than the 

igneous rock of the vicinity. In some cases the content is several 

times greater, but this result is not general. In fact, the nearly pure-, 

silica deposits from most of the geysers and the older springs contain-, 

less than half as much radium as the underlying rhyolite. The location of the springs appears to be related to the radium content of the 

residue. The residues with a radium content greater than that of 

adjoining rocks come, as a rule, from relatively new springs which 

are close to the outcropping rock. The disintegrated rock material 

from the so-called mud pots, paint pots, and mud volcanoes were 

also found to contain more radium than the park rhyolite.

Radioactive equilibrium. Another question naturally arises in this, 

connection: Is the radium thus deposited in radioactive equilibrium, 

with its parent uranium ? Some experimental evidence obtained, 

indicates that far less uranium is deposited than the radium content 

requires. Of course, the quantity of uranium considered here is too 

small to be detected by chemical analysis, but if radium were present 

in the equilibrium ratio the activity of the deposits would remain 

practically constant for years. Now, the radium present in the old 

terraces, long since dry, is considerably below the average value for 

the recent deposits. A sample of travertine from Terrace Mountain, 

the scene of the first hot-spring activity at Mammoth Hot Springs,, 

contains only about 1 per cent of the radium found in the present-day 

deposits of Jupiter terrace and Main terrace. Again, a sample of 

travertine from Hotel terrace, on which the government fort and 

buildings stand, carried only about 40 per cent of the radium found 

in most of the present-day deposits. Of course, these results might; 

possibly be attributed to loss of radioactive material through weathering; but the hypothesis that radium and uranium are not deposited, 

in radioactive equilibrium also furnishes a satisfactory explanation 

for the fact.

Estimate of age of deposits. If we start with a given quantity of 

radium, separated from its parent uranium, at the end of 2,600 years, 

SSS65 Bull. 395 09 3
34 EADIOACTiyiTY OF THERMAL WATERS

according to recent determinations, one-half of it would be transformed into inactive products, at the end of another such period 

there would be only one-fourth of the original amount, and so on. If 

we assume, then, that the uranium, deposited with the radium is far 

below the equilibrium quantity, the experimental results obtained 

follow. Moreover, from the data thus in hand the approximate age 

of the old deposits can be calculated. . The application of these data 

to the question of the age of the deposits of course involves the assumption that the original radium content of the travertine in the / 

old terraces was approximately the same as in the new. Such an 

assumption is not far from the truth. The similarity of the waters 

of this locality as a whole in regard to their radioactive content, as 

well as in other respects, is very close and indicates a common origin. 

Moreover, some of the old terraces are well within the zone of present 

activity. The travertine of Terrace Mountain is overlain by glacial 

bowlders. Since its activity is only 1 per cent of that of the recent 

deposits, its age is about 20,000 years,0 which would also be the 

approximate time that has elapsed since the glacial period in the park. 

Comparative .test for uranium l>y analysis. Another line of experiments bearing on this question was suggested by some results obtained 

quite recently in determining the radium present in some of the 

"tufa" deposits made by the springs at Hot Springs, Ark. These 

deposits, like the travertine at Mammoth Plot Springs, are calcareous. The radium content b of one of these deposits indicated the 

presence of about one-half of 1 per cent of uranium, a quantity well 

within the range of analytical methods. Investigation of the question from this standpoint would be of interest. The deposit in question, which was obtained from the Palace Spring, is three times as 

active as the famous Bath Springs of England tested by Strutt.

RELATION TO HYDROTHERMAL ACTIVITY.

I

Assuming that the thermal activity in the park is due to recent f 

extrusive lava flow, or intrusive lava masses, the question arises to 

what extent the radium content of these rocks affects their rate of 

cooling. To what extent is the radium responsible for the continued 

hydrothermal activity? We have attempted no calculations with 

the data obtained from the Yellowstone Park rocks, for we do not 

know the volume of water discharged by these springs, and so lack 

data for calculating the heat dissipated by the water. At Hot 

Springs, Ark., the present flow from the springs is given by Hay wood 

and Weed c in their reports on the Hot Springs of Arkansas, at 850,000

a This would be 14,000 years if we accept 2,000 years as the half-time period of radium.

*>Trans. Am. Electrochem. Soc., vol. 12, 1907, p. 247.

c Hay wood, J. K., Report of an analysis of the waters of the hot springs on the Hot Springs Reservation, 

Ark.; and Weed, W.H., Geological sketch of the Hot Springs district: 57th Cong., 1st sess., S. Doc. No. 282 

1902 pp. 31, 93.
OF YELLOWSTONE NATIONAL PAEK. ' .35

gallons daily. A simple calculation shows that the heat dissipated 

by the springs, flowing at the present rate during ten thousand years, 

would be furnished by approximately one cubic mile of solid lava 

cooling from its fusion point to the temperature of boiling water. 

Assuming that the radium present in the rocks is even somewhat 

greater than the average value found by Strutt a and by us, for igneous 

rocks (say 5xlO~12 grams per gram of rock), the heat supplied by 

it per cubic mile of rock is about one-tenth of 1 per cent of the heat 

dissipated by the water.

The rock samples tested for radium gave values that average oi\\y 

a little more than Strutt's average for rhyohtes and basalts about 

2 x 10~12 grams radium per gram of rock. These data certainly 

seem, to indicate that the hydrothermal activity so manifest in the 

park is not connected with localized deposits of radium. In the 

above calculations the question of heat lost by diffusion and other 

factors is not taken into consideration, but after allowing a generous 

margin for error we do not see how more than 1 per cent of the heat 

required for the hydrothermal'action can be ascribed to the radium 

content of the rock. It is true that a sample of limestone from 

Mammoth Hot Springs, which Arnold Hague considers typical of the 

underlying Mesozoic limestones, is more active than the most active 

of Strutt's sedimentary rocks, 6 a sample of oolite from the neighborhood of the Bath thermal springs of England, but this coincidence 

alone is not of sufficient importance to justify a verdict.

a Prop. Roy. Soc., vol. 77, p. 472. b Idem, vol. 78, p. 150.

o
" * " 

/*