MANUFACTURE OF SULPHATE OF COPPER. 
237 
articles formed of brass and other metallic alloys are also dipped 
in the same pickle, the sulphate of copper thus obtained cannot be 
pure. Again, a mixture of nitric and sulphuric acid is sometimes 
employed, constituting another source of impurity. 
In Birmingham, some hundred tons of dipping-liquor are annual- 
ly made, and employed in the manufacture of sulphate of copper; 
the consequence being that the sulphate contains a large portion of 
zinc, which may sometimes be seen in the form of slender white 
needles on the surface of the dark blue crystals. Nickel, lead, 
arsenic, and antimony are sometimes present in the so-called sul- 
phate of copper, manufactured either partly or entirely from the 
pickle or dipping-solution. 
In addition to its medicinal uses, this salt is extensively applied 
in the arts, particularly in the manufacture of Scheele's or 
emerald green, and other pigments. Large quantities of sulphate 
of copper are also disposed of in the autumn and spring in the 
agricultural districts, it having been found that seed-corn steeped 
in a solution of this salt previous to being sown, is an effectual re- 
medy against the disease of wheat called the " smut." 
The impure sulphate of copper before mentioned, which is sold 
at 4s. to 5s. per cwt. below the price of good sulphate, will do 
very well for agricultural purposes, but as sulphate of zinc is not 
equally efficient for preventing the smut, the farmer must employ 
a larger quantity of the impure salt to effect the desired purpose, 
and thus gains nothing from its use. The very impure sulphate of 
copper is of a much lighter colour than the genuine salt. Sul- 
phate of copper from sources likely to be dashed with the contents 
of the pickling or dipping-pot, should at all times be viewed with 
much suspicion. — Pharm. Journal and Transactions, April 1851. 
ON THE MILKY JUICE OF THE LETTUCE AND THE POPPY. 
By Aubergier. 
Aubergier cultivated Lactuca sativa and the poppy on the large 
scale in order to obtain lactucarium and opium. In lactucarium 
he found lactucin, mannite, resin, cerin, asparamid, a brown color- 
