998 Wisconsin Academy of Sciences, Arts, and Letters. 
Chemical Properties. 
Loss in weight on heating: Hill (1913) stated that the oleo- 
resin when heated at 100 °C should not lose more than 6 per 
cent, of its weight, a greater loss indicating the presence of 
unevaporated solvent. The statement is confirmed by other 
data of this nature reported in the literature as well as by 
the results obtained in the laboratory as is shown in the tables 
which follow: 
Table 17 — Laboratory preparations—Loss in weight on heating. 
Sample 
No. 
Date 
Observer 
Solvent 
Per cent 
of loss on 
heating- 
1 . 
1.887 
Kremel. 
Alcohol. 
At 100 « C 
17.40 
2 
Ether...... 
0.70 
4.51 
] 
1904 
Dieterich... 
1 
1916 
DuMez. 
Acetone... 
At 110° C 
2.51 
2.37 
2 
Ether.. 
