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Report OF THE CHEMIST OF THE 
its composition in detail. Suffice it to say that most of the copper 
carbonate we have to deal with contains, if pure, in 100 pounds: 
Pounds 
Copper.’ : . ...) (MMMM. CORI ecai Gi... ee os 57.4 
Carnor <2) cues Pcs) s + <> vw em se beei- .. + s os 5.4 
3. eqs) eR. CR i OA SS 36.3 
PLY GLOLED 0) sks RR Sc ale) CSTE. 5 cs «CUMMING a oo adies Je alae 0.9 
It is known in nature in crystalline form under the name of 
malachite. Copper carbonate, when made by precipitation, as is 
the case in the common methods of artificial preparation, is a 
greenish powder. Unless thoroughly washed, it will contain 
some sulphate, when made in the ordinary way. The sulphate 
probably does no harm in spraying mixtures when the quantity is 
small, } 7 
) ANALYSES OF COPPER CARBONATE. 
1. The first sample of copper carbonate examined was obtained 
at one of the Geneva drug-stores. It contained 88.1 per cent. of 
copper carbonate. The sample dissolved to a clear solution in 
acids, except a small amount of dirt which remained in suspension. 
The diminished per cent. of copper carbonate was probably due 
to the presence of some moisture, though this was not determined. 
2. The second sample was obtained from another drug-store in 
Geneva. It contained 62.8 per cent. of copper carbonate. This 
sample contained a considerable quantity of some kind of white 
powder, which failed to dissolve in nitric. acid. The presence of 
this insoluble matter, coupled with the low per cent. of copper 
carbonate, gave evidence of serious adulteration. With pure 
copper carbonate at forty cents a pound, this sample was worth 
not over twenty-five cents a pound. | 
3. The third sample of copper carbonate came from W. S. 
Powell & Co., Baltimore, Md., and was put up for the season 
of 1892. It contained 89.4 per cent. of copper carbonate. It was 
found to be not entirely free from sulphate. It did not make a 
perfectly clear solution in acids. 
4, The fourth sample was called “hydrated copper carbonate. 
- So far as could be ascertained, this “hydrated” compound is’ 
nothing more than the ordinary copper carbonate saturated with 
water. Taking the mixture as it was, it contained 59.4 per cent. 

