634 Lester — Radioactive Properties of the 



very unlikely that results would be obtained commensu- 

 rate in interest with the labor involved. 



Some work has been done on a few of the springs 

 listed in Table I by other observers. Wolcott 7 examined 

 one spring at Glenwood Springs but his method gave 

 qualitative results only. The work of Headden 8 on the 

 Doughty Springs (Nos. 73-77) near Hotchkiss, Colorado, 

 was done by the photographic method and the results 

 given are also qualitative. A few of the springs at Mani- 

 tou, Colorado, were examined by Shedd 9 and his results 

 show a fair agreement with later observations consider- 

 ing the lack of precision in his apparatus and the fact 

 that he did not use an emanation standard. 



The most extensive previous investigation is that of 

 Schlundt 10 who tested a number of springs near Boulder, 

 at Manitou, at Steamboat Springs, and at least one 

 spring at Glenwood Springs. He used a fontactometer 

 having a volume of about 15 liters. His results which 

 can be identified with springs listed in this work are also 

 given in Table I and are indicated by the letter S. The 

 two sets of measurements sometimes agree but often 

 one of them differs by amounts ranging from about one- 

 fourth to -&ve times the other. These differences are due 

 partly to the methods used, to the corrections applied, 

 and partly perhaps to variations in the activity of the 

 sources. An examination of the two sets of temperature 

 readings indicates that changes have occurred in the con- 

 dition of some of the springs. Likewise the testimony of 

 local observers seems to show that springs in a rather 

 closely associated group sometimes change their char- 

 acter due apparently to connection by means of under- 

 ground channels. The differences in the measurement of 

 activity, however, appear to have no relation to these 

 indicated changes. 



Considered as a whole the results given in Tables I and 

 II indicate a high average activity although there are a 

 few springs which are inactive. The most active waters 

 show the highest radioactivity yet found in the United 

 States and are surpassed by but few foreign springs. 

 The greatest activity found in the spring gases is 

 exceeded in the United States by a few springs in the 



7 Biennial Keport Colo. School of Mines, Appendix p. 27, 1904. 



8 This Journal, 19, 297, 1905. 



9 Proc. Colo. Sci. Soc, 10, 233, 1912. 

 10 Loe. cit. 



