INSECT POWDER. 
37 
mercial insect powder: Maximum size, 255 microns; moisture, 5.55 
to 13.95 per cent. In the Erstes Dezennium der Helfenberger 
Annalen, 1886-95 (page 420), as the average of all determinations 
made on insect powders during that period, the following are given 
as the limiting values: Moisture (loss at 100°), 5.55 to 13.95 per 
cent; ash, 6.07 to 8.70 per cent; potassium carbonate in ash, 28 
to 38.33 per cent; maximum size of particles, 109.44 to 175.50 
microns. 
Table 13. — Chemical analysis of insect powders (Dieterich). 
Year. 
Determination. 
Maximum 
size of 
particles. 
Sample No. 
Moisture 
(loss at 
100°). 
Ash. 
K 2 C0 3 in 
ash. 
1 
1 1896 
Per cent. 
| 9.55 
{ 8.25 
{ 11. 18 
{ 12. 12 
9.53 
1 11.12 
I 10. 60 
{ 11. 26 
6.95 
Per cent. 
8.35 
7.65 
7.58 
7.38 
6.61 
7.45 
6.80 
8.06 
6.40 
7.13 
7.56 
8.75 
6.38 
6.90 
6.65 
7.63 
9.94 
9.63 
7.01 
6.39 
6.16 
7.40 
6.75 
7.30 
6.35 
Per cent. 
23.47 
31.57 
30.96 
33.80 
38.05 
17.01 
33.51 
Microns. 
179. 55 
2 
255. 15 
3.. . 
151. 20 
1 
190. 35 
2 
1 1897 
1900 
139. 05 
3. . 
153. 90 
4 
141. 75 
1 
148. 50 
2 
311.85 
3 
302. 40 
4. . 
9.93 
9.33 
141. 75 
155. 25 
fi... 
155. 25 
7 
I 7.43 
f 10. 33 
J 11. 97 
1 9.28 
198. 45 
198. 45 
2 1 
145. 50 
3. . 
> iyui 
4 
] 
I 1902 
1 1903 
1904 
1 
| 7.97 
\ 8.83 
I 10.52 
I 10.04 
{ 8.57 
I 9.05 
8.81 
202. 50 
2 
135. 00 
3 
67.50 
1 
190. 35 
2 
162. 00 
3 
135. 00 
1 
162. 00 
In the Helfenberger Annalen for 1902 (page 186), Dieterich reports 
the results of the determination of the ether extract of insect powders, 
using the method of Fromme (85), in which 8 grams of powder are 
treated with 80 grams of ether of specific gravity 0.720 at 15° C, 
shaken at intervals during 1 hour, then 50 grams (=5 grams powder) 
shaken with 1 gram of water, filtered, the filter thoroughly washed 
with ether, and the filtrate evaporated and weighed. The extract 
of insect powders made in this way varied from 5.16 to 5.38 per cent. 
Durrant (73) is the author of the ether extraction method that 
has been most generally applied in the valuation of insect powder. 
He proceeds as follows: 
Place 100 grains of the powder in the cylinder of a glass syringe (1 ounce). The 
powder should be pressed down compactly on to a piece of absorbent cotton to act 
