70 ROYAL SOCIETY OF CANADA 
It will be seen: (1) that the insoluble portion contained about 
four times as much radium as the soluble; (2) that there is no definite 
relation between depth and quantity of radium; (3) that the mean 
value agrees well with determinations by Strutt and by the writers. 
It is remarkable that radium should be distributed with so little 
variation in the sedimentary rocks, the values ranging only from 3 
to 0.3, whilst the mean value for a number of specimens from different 
localities is approximately 1 for sedimentary, and 2 for igneous rocks. 
