466 



same electroscope was used, but two shaking cans were used, the larger 

 of which had three stop cocks so that two volumes of water could be had. 



TABLE 4. 

 C. J. S. Spring. August 5, 1914. Temperature of water 12.5° C. Temperature of air 30° C. 





I. 



II. 



III. 





11.03 a.m .". 



.707 liters 



.943 



425..X10-" 



11.46 a. m 



3.00 liter 



2.00p.m. 

 5 . 00 liter. 







4.10 



435 X10-"= 



2.10. 



Curies X10" 12 per liter 



443 XlO-i-. 







These observations were taken every minute and the mean deflection 

 from 15 minutes to 20 minutes from the time of putting the emanation in the 

 ionization chamber, was used. By referring to an experimental curve (Fig. 

 8), the maximum deflection per minute or the defletation at the end of three 

 hours was calculated. A better agreement could have been obtained if the 

 interval from the end of one experiment to the beginning of the next had been 

 three hours or more. 



Fig. 8 is a curve showing actual observations during a period of three 

 hours taken with a sample of water from Hottle Spring. The observations 

 have been reduced to a scale of 100% for the maximum. The curve marked 

 "Decay A and C" is made by observing the deflections after the emanation 

 has been pumped out. By means of this experimental curve observations at 

 any time can be reduced to the maximum or three-hour values. For exact 

 work the emanation should be placed in the electroscope and allowed to stand 

 for three hours and several observations made and the mean used. The 

 curve is for all practical purposes horizontal from three to four hours. 



In all these observations the deflections have been corrected for the 

 natural leak of the electroscope due to the natural ionization of the air. 



Before giving results, I shall speak off some factors which may influ- 

 ence the results. Since the emanation gas is dissolved in the water and is 

 removed by boiling or by shaking, care should be used in filling the shaking 

 can. Immerse the can in a pool as close as possible to the source and allow 

 the water to flow in gently. Filling by dipping and pouring with a smaller 

 vessel removes some of the gas. If before the water issues from the ground 

 it trickles over rocks in the presence of air which is not charged with emana- 



