﻿126 BACON. 



equilibrium exists between uranium and radium with possibly actinium 

 as an intermediate product. This much radium would evolve about 70 

 gram calories per hour, 23 an amount of heat which with perfect insula- 

 tion, would require five hundred and forty days to increase the tem- 

 perature of one ton of substance of specific heat 1, by 1°, but perfect 

 insulation is not conceivable within the earth's crust. 



The above calculation is based on the limit value of the heat which 

 would be possible if we were to encounter a volcano of pure uranium, and 

 which would therefore contain the maximum amount of radium which 

 experimental facts at present show to be possible, and the amount of 

 radium actually found in rocks and minerals is but ICHto 10~ 5 times 

 this quantity. 



In addition to these considerations the fact remains that the waters 

 and sediments from the crater of Taal volcano were found to contain 

 almost no radium. 



23 Rutherford: Radioactivity (1905), 419. 



