636 Lester — Radioactive Properties of the 



La Veta and No. 71 near Hartsel in South Park are in 

 regions where radioactive ores occur to some extent. 

 Autunite is found in the La Veta region and some Carno- 

 tite in South Park. Generally speaking, however, the 

 most active springs are found on both slopes of the Conti- 

 nental Divide and not far from it. So far as is known 

 there are no bodies of radioactive ores near them. 



In the course of this work there were found many 

 groups of springs situated just at the foot or within a 

 mile or two of a high mountain range the individual peaks 

 of which reach elevations as high as 12,000 to 14,000 feet. 

 These groups are sometimes arranged in a more or less 

 definite line a mile or more in length as if along an old 

 fault and again are gathered together in an irregular 

 area the opposite sides of which are only a few hundred 

 feet apart. In such areas springs as widely different as 

 a cold soda spring and a hot sulphur spring may be found 

 separated by only a few feet. These areas seem to be 

 merely the common outlets for underground waters 

 draining often from many square miles of high mountain- 

 ous country which frequently includes formations of 

 widely different age and character. 



As to the origin of the radioactivity found in natural 

 waters there seems to be a general agreement that it is 

 picked up little by little during the underground flow 

 from the minute amounts of radioactive matter known to 

 be widely diffused through all rocks and soils. Accord- 

 ing to Dienert and Guillard 12 the activity arises exclu- 

 sively from this source. They point out further that 

 when water comes from great depths as in Plombieres it 

 is possible to find springs very near together, coming 

 from the same geological beds and having very different 

 activity. The work of Schmidt and Kurz 13 indicates 

 that there is no dependency of emanation content on 

 depth, strength of flow, chemical properties or tempera- 

 ture, but only that springs from eruptive rocks are in 

 general much more active than those from sedimentaries. 

 The question as to whether an underground water or 

 gas collects most of its radioactive material near the out- 

 let or far removed from it, whether by gradual absorption 

 from surrounding rock or by rapid absorption during a 

 brief contact with more active material, does not seem to 

 be answerable without more information than is usually 

 known about the underground course. Mining opera- 



12 Le Radium, 7, 60, 1910. 



13 1 Phys. Zeitschr., 7, 209, 1906. 



