10 
BULLETIN 1147, U. S. DEPARTMENT OF AGRICULTURE. 
Zinc arsenite is made by heating together arsenious oxid, zinc 
oxid, and water. It is sold only as a powder. The arsenious oxid 
content of the two samples (Nos. 23 and 33) analyzed is approxi- 
mately the same as the average arsenic oxid content of the calcium 
arsenates on the market. The water-soluble arsenious oxid figures 
are a little higher than the results for the best grade of lead or calcium 
Table 4. — Composition of miscellaneous arsenicals. 
Sample 
No. 
Material analyzed. 
Moisture. 
Total 
arsenious 
oxid 
(AS2O3). 
Total 
arsenic 
oxid 
(As a 5 ). 
Water- 
soluble 
arsenious 
oxid 
(AS2O3). 
23 
Commercial zinc arsenite 
Per cent. 
0.15 
.06 
.53 
3.15 
1.03 
2.96 
.29 
1.78 
10.29 
3.40 
6.32 
37.54 
.35 
6.41 
Per cent. 
41.49 
42.54 
55.09 
Per cent. 
Per cent. 
0-52 
33 
do.... 
.85 
64 
1.94 
36 
Commercial calcium and lead arsenates 
46.17 
21.95 
33.60 
30.93 
14.36 
37.65 
45.16 
59.80 
37.99 
59.39 
.25 
8 
Commercial calcium and lead arsenates plus 
calcium carbonate 
62 
Commercial magnesium arsenate 
71 
Laboratory barium arsenate 
74 
Laboratory copper and barium arsenate 
Laboratory aluminum arsenate 
73 
31 
Commercial sodium arsenate 
41 
do 
Laboratory sodium arsenate 
25 
26 
90 
31.10 
1.41 
Sample 
No. 
Material analyzed. 
Water- 
soluble 
arsenic 
oxid 
(As 2 5 ). 
Oxid. 
Carbon 
dioxid 
(COs). 
Undeter- 
mined. 
Per cent. 
Commercial zinc arsenite. 
.....do 
Per cent. 
56.30 (ZnO) 
Per cent. 
Commercial Paris green 
Commercial calcium and lead arsenates . 
Commercial calcium and lead arsenates plus 
calcium carbonate 
Commercial magnesium arsenate. 
Laboratory barium arsenate 
Laboratory copper and barium arsenate. 
Laboratory aluminum arsenate 
Commercial sodium arsenate 
.do. 
Laboratory sodium arsenate 
Laboratory potassium arsenate. 
Commercial London purple 
1.14 
.53 
1.56 
.21 
.90 
.72 
45.16 
59.80 
37.99 
59.39 
.25 
56.46 
8.29 
.17 
5.98 
37.45 
46.37 
2.11 
34.32 
64.96 
11.18 
47.47 
16.84 
45.76 
27.66 
19.35 
36.00 
34.88 
(ZnO) 
(CuO) 
(CaO) 
(PbO) 
(CaO) 
(CaO) 
(PbO) 
(MgO) 
(BaO) 
(CuO) 
(BaO) 
(Al a 8 ) 
(Na 2 0) 
(Na 2 0) 
(Na 2 0) 
(K 2 0) 
(CaO) 
i 1.50 
} 23.23 
.55 
1.33 
} .. 
.37 
Per cent. 
2.06 
.94 
35.92 
5.75 
5.31 
28.57 
2.49 
25.08 
35.22 
5.68 
6.22 
5.12 
4.26 
22.99 
arsenates. For more detailed information, the publication of Schoene 
(44) on zinc arsenite should be consulted. 
Magnesium arsenates. — It is theoretically possible to prepare 
ortho, meta, and pyroarsenates of magnesium in the same manner 
as the corresponding arsenates of lead. Practically twice as much 
magnesium, calculated as magnesium oxid, was found in the sample 
analyzed as is needed to combine with the arsenic oxid present. 
Patten and O'Meara (30) give analytical results on a magnesium 
arsenate containing 32.13 per cent of arsenic oxid and 1.25 per cent 
of water-soluble arsenic oxid. They found 41.7 per cent of the 
total arsenic to be soluble in water containing carbon dioxid. A 
commercial magnesium pyroarsenate analyzed by them had a low 
