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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 miscelltnirous arsrnirals. 



Sample 

 No. 



Material analyzed. 



Moisture. 



Total 

 arsenious 



oxid 

 (As 2 3 ). 



Total 

 arsenic 



oxid 

 (As 2 Oi,). 



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. 







46.17 



21.95 

 33.60 

 30.93 

 14.36 

 37.65 

 45.16 

 59. SO 

 37.99 

 59.39 

 .25 





















31.10 



Water- 

 soluble 

 arsenious 



oxid 

 (As 2 3 ). 



Commercial zinc arsenite 



do 



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 



Per cent. 

 0-52 

 .85 

 1.94 



Sample 

 No. 



Material analyzed. 



Water- 

 soluble 

 arsenic 



oxid 

 (As 2 5 ). 



Oxid. 



Carbon 

 dioxid 

 (CO,). 



Undeter- 

 mined. 



Commercial zinc arsenite. 

 do 



Per cent. 



Commercial Paris green 



Commercial calcium and lead arsenates. 



Per cent. 



56.30 (ZnO) 



56-46 (ZnO) 



8.29 (CuO) 



.17 (CaO) 



5.98 (PbO) 



37.45 (CaO) 



Per cent. 



Commercial calcium and lead arsenates plus 

 calcium carbonate 



Commercial magnesium arsenate 



Laboratory barium arsenate 



Laboratory copper and barium arsenate. 



Laboratory aluminum arsenate 



Commercial sodium arscna t c 



do 



Laboratory sodium arsenate 



Laboratory potassium arsenate 



Commercial London purple 



.53 



1.56 



.90 



.72 

 45.16 

 59. 80 

 37.99 

 59.39 



.25 



46.37 

 2.11 

 34.32 

 64.96 

 11.18 

 47.47 

 16.84 

 45.76 

 27. 66 

 19. 35 

 36.00 

 34.88 



(CaO) 



(PbO) 



(MgO) 



(BaO) 



(CuO) 



(BaO) 



(A1 2 3 ) 



(Na 2 0) 



(Na 2 0) 



(Na 2 0) 



(K 2 0) 



(CaO) 



1.50 



.55 

 1.33 



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 {SO) 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 



