Headden — Group of Radium-hearing Springs. 309 



The close relationship between barium and radium and the 

 well-known fact that barium possesses the property of carrying 

 down other substances with it when precipitated from its solu- 

 tion and radium in a very high degree, made it almost certain 

 that I would find this sinter to contain radium provided any 

 at all were present in the springs. 



I was forced to depend upon its action on the photographic 

 plate in testing for it. The action of the sinter as it was 

 broken from the bed, always from points near or at the springs, 

 was of course weak compared with the action of Gilpin 

 County pitchblende, but it was always present and could be 

 seen during the development of the plate even if it were 

 invisible after fixing and drying, 



In one experiment made to test the action of the sinter in 

 comparison with that of pitchblende the plate was covered 

 with two thicknesses of black paper and a piece of pasteboard 

 and the exposures made for five days ; the radiograph obtained 

 with the pitchblende was distinct but not sharp; the plate 

 exposed to the action of the sinter showed the stencil used 

 while it was being developed, but not when fixed and dried. 



I next undertook the preparation of radiferous barium 

 chloride. For this purpose I fluxed 13 pounds of sinter with 

 sodic carbonate, washed, dissolved in HC1, removed silica and 

 iron by usual methods and crystallized out the baric chloride ; 

 the yield of crude BaCl 2 was eight pounds. This was subjected 

 to fractional crystallization at last from HC1 solution. When 

 the mass of BaCl 2 amounted to rather less than 2 ozs. it was 

 allowed to stand for 15 days to regain its j8 and <y rays and 

 then tested. This preparation gave an impression upon the 

 plate after an exposure of 2| days comparable to that made in 

 five days by pitchblende. The distance between the film and 

 the salt was from 0*25 to 0*5 centimeters and the plate was 

 covered with two thicknesses of black paper. I did not deem 

 it necessary to carry this work further for the purposes of this 

 immediate work. 



So far as I am able to discover, this group of springs is 

 unique in that it is depositing a baritic sinter, and also in the 

 presence of radium in comparatively large quantities. 



State Agricultural College, 



Fort Collins, Colorado. 



