rset. by LE RA ee Oe ee ee ee ae 
IPRS aN Mee gaia a) 
ria Peat x kel, 3 Se. . 


394. | Report OF THE CHEMIST OF THE 
composition in a somewhat different form, we can say that crystal- 
lized copper sulphate contains in 100 pounds: 
Pounds. 
WOPDer\. s/s. )s scam 1 RRR ie sea vee so an 25.4 
Pulpnuric. acid: (game ed.):.\ 7 eee, ok ie Rigle\s oss 0 oss ne 38.6 
PWVALOT s 5 tis ..s ee a AN, 2 SS A 0 Dehn 36.0 ) 
Now, if we heat 100 pounds of copper sulphate in an oven to 
the temperature of boiling water, the crystals will gradually lose 
their color and crumble to pieces, leaving a bluish-white powder. 
At this temperature, twenty-nine of the thirty-six pounds of water 
are driven off. If this powder is heated to 400° F, the remaining 
seven pounds of water will be driven off and we’shall obtain a — 
white powder, which is called anhydrous or dehydrated copper 
sulphate ; that is, copper sulphate free from water. This form of 
copper sulphate is being put upon the market for spraying mix- 
tures. It has the advantage of being in a finely powdered condi- 
tion and in a more concentrated form, containing, as it does, if 
pure, forty pounds of copper per hundred. It possesses the 
disadvantage of absorbing moisture from the air rapidly, which 
renders the composition uncertain. 
ANALYSES OF COPPER SULPHATE. 
1. The first sample of copper sulphate examined was obtained | 
-by Mr. D. G. Fairchild from the Nichols Chemical Company 
(Laurel Hill Chemical Works), 45-49 Cedar street, New York 
city. This sample contained 99.6 per cent. of copper sulphate. 
This was practically pure. In order to make sure that this 
sample was not misleading, another sample was obtained from the 
company through Mr. Morton Minot of Brockport, and thus gave 
the same results, on analysis, as the first sample. 
2. The next sample of copper sulphate was obtained from one 
' of the drug stores in Geneva. It contained 98.1 per cent. of 
copper sulphate. 
3. The third sample of copper sulphate was sent to the Station 
for analysis by Mr. J. Burroughs, West Park, N. Y. It contained 
98.6 per cent. of copper sulphate. This sample contained a con- 
siderable amount of free cr uncombined sulphuric acid, which_— 
had partially destroyed or eaten the paper wrapped around it 

