

400 Report OF THE CHEMIST OF THE ~ ; 
samples that were tested for sulphate showed its presence, but 
probably not to an injurious extent. 
3. ‘ Copperdine,” in dry form, costs the fruit-grower twice as 
much as he himself could prepare it for, but contains the proper 
amount of copper. 
“ Copperdine” in liquid form, as put up in 1891, cost three or 
four times as much as it could be prepared for, and contained 
only one-half or one-third as much copper as it should. It was, 
therefore, worse than worthless, since its use would mislead fruit- 
growers. However, the sample for 1892 proved to be up to offi- 
cial strength. The samples of copperdine for 1892 showed the 
presence of sulphates. 
4. The “prepared” Bordeaux mixture for 1892 does not appear 
to be up to the required official strength. 
How To Detect IMPURITIES IN CoPPER COMPOUNDS. 
While the help of a chemist is needed to tell how much copper 
a substance contains, a few suggestions may be given which will 
enable anyone to test roughly samples of copper sulphate and 
copper carbonate, as well as Paris green, in regard to their’ 
purity. 3 
1. Copper sulphate, if pure, should dissolve completely in warm | 
water, making a clear solution, free from sediment or suspended 
matter. 
2. Copper carbonate should dissolve completely in nitric acid, 
commonly called aqua fortis. If it does not dissolve completely, 
it is impure and probably adulterated. Copper carbonate, if 
pure, should also dissolve completely, or nearly so, in strong 
ammonia water, used in considerable quantity. Both the fore- 
going tests should be applied. Of course, copper carbonate 
could be adulterated by using finely powdered or dried copper 
sulphate, but this could easily be detected by treating with water, 
since copper sulphate easily dissolves in water, while copper 
carbonate does not. 
3. Paris green should, if pure, dissolve completely in strong 
ammonia water, used in liberal quantity. | 
Such simple tests as the foregoing may be applied by anyone, 
and while they will not prove an infallible guide, they will serve 

