214 Preparation of Zirconia for the Oxy-hydrogen Light. 
The cylinder in which the pencils have been compressed is 
about two centimeters in diameter and four centimeters in 
length; the cavity running centrally through it is six milli- 
meters in diameter, the piston rod fits closely, and both it 
from the zirconia prepared in the manner related above have 
been tested alongside of those made from zirconia prepared by 
erck, which is stated to be pure, and is sold at the rate of 
one dollar per gram. Whatever the process may be that Is 
used in its preparation it does not give a product as free from 
iron and silica as the one which I have described, nor does It 
possess the same illuminating power. 
June 22d, 1877. 
