RECOVERY OF ACTINIUM AND IONIUM FROM OLARY ORES. 41} 
dryness, the residue is taken up with water and the silica 
filtered off. 
4. The solution is saturated with gaseous hydrogen 
chloride and the radium and barium quantitatively pre- 
cipitated. 
The solution contains the actiniferous rare earths. It 
is evaporated to dryness to expel the excess of hydrogen 
chloride, and the residue is then treated for the separation 
of the actinium. 
It is hoped that ultimately sufficient material will be 
available to allow of pure salts of actinium being prepared. 
The determination of both the atomic weight and the 
period of actinium is much to be desired, as a knowledge of 
these two constants would fix the position of actinium and 
its products in the disintegration series of the radioactive 
elements. 
