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The presence of the free sulphuric acid would not rerder the 
copper sulphate injurious, if it were intended for use in the 
Bordeaux mixture or for the preparation of copper carbonate, 
since, in either case, the free acid would be completely removed 
or neutralized in such a way as to form a harmless compound. 
4. The fourth sample of copper sulphate examined was in 
powdered form ; that is, the ordinary crystallized copper sulphate 
reduced to a fine powder by grinding. This was obtained from 
W.S. Powell & Co., Baltimore, Md., and contained 98.1 per cent. 
of copper sulphate. This sample contained noticeable quantities 
of dirt, which was present probably by accident rather than by 
design. It is readily seen that powdered copper sulphate offers a 
better opportunity for adulteration than do the large crystals. 
5. The next sample was crystallized copper sulphate, sent out 
by W. S. Powell & Oo. for the season of 1892. It contained 99.6 
per cent. of copper sulphate. 7 
6. The sixth sample was powdered crystallized copper sulphate, 
from W. 8S. Powell, for the season of 1892. It had evidently lost 
some of its water of crystallization and was, therefore, found to 
contain about one per cent. more of copper than ordinary crys- 
tallized copper sulphate. The sample contained a small amount 
of insoluble dirt. 
7. The seventh and last sample of copper sulphate was called 
“dried copper sulphate,” and was sent out by W.S. Powell & Co. 
for the season of 1892. This sample was found to contain 90.8: 
per cent. as much copper sulphate as copper sulphate which has 
been thoroughly dried at 212° F’. should contain, or 81.8 per cent. 
as much as should be contained in copper sulphate which has 
been dried completely at 400° F. Copper sulphate in this form 
very readily absorbs moisture, and the diminished per cent. was 
doubtless due to the fact that after it was dried it absorbed some 
moisture. The sample contained some dirt, The main objection 
to be urged against buying copper sulphate in this dried form is 
that the composition is very apt to be uncertain, owing to its 
tendency to absorb moisture when it is exposed to the air. 
PROPERTIES OF COPPER CARBONATE. 
Copper carbonate is a somewhat complex chemical compound, 
and it would take us too far into chemistry to attempt to explain 
