356 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
lowed to cool, filtered in a Buchner funnel, washed free from chloride, 
dried at a low temperature, and weighed. In laboratory practice the 
recovery on the basis of the original calcium content averaged nearly 
Analyses of Acid Calcium Arsenate 
No. 12 
No. H 1-7 
Theoretical 
CaHAs0 4 .H 2 0 
Character of product. 
dry powder 
dry powder 
Color..... 
white 
white 
Shape of particles.. 
rhombic crystals 1 
rhombic crystals 1 
Size—length 2 .. 
5—32yU aV. 19yU 
4-28m av. 17m 
breadth 2 . 
2-11^ av. 6 m 
2-1 6m av. 9 m 
Uniformity 2 . 
variable in shape 
variable in size 
and size 
Nature of defects 2 .. 
broken crystals 
broken crystals 
Amount of defects 2 . 
50 per cent 
1 per cent 
On dry 
On dry 
Air dry, 
basis, 
Air dry, 
basis, 
Per cent 
per cent 
per cent 
per cent 
per cent 
Water... 
.20 
.12 
Calcium oxide (CaO). 
28.25 
28.306 
28.30 
28.334 
28.310 
Arsenic pentoxide (As 2 0 5 ).. 
57.91 
58.026 
57.955 
58.025 
58.045 
Water of combination. 
13.65 
13.676 
13.63 
13.646 
13.645 
100.01 
100.008 
100.005 
100.005 
100.000 
Arsenic (As).. 
37.836 
37.835 
37.848 
1 For description see Gmelin-Kraut’s Handbuch der anorganischen Chemie, Bd. 
3, Abt. 2, pp. 568-569 (1908). 
2 Determined by A. I. Bourne of the Entomology Department. 
Solubility of Acid Calcium Arsenate 
No. 12 
per cent 
No. H 1-7 
per cent 
Water.... 
.20 
.12 
Water soluble (Hilgard method). 
Calcium oxide.. 
22.50 
Arsenic pentoxide... 
50.52 
44.82 
Solids 
74.20 
Lime water soluble. 
Arsenic pentoxide.. 
.31 
.17 
