ON PRECIPITATED CARBONATE OF ZINC. 
91 
extractive, volatile aud fixed oils, lignin,and a peculiar 
principle, which, as it embodies the diuretic power of the 
leaves, may be called TJrsin. This principle is worthy of a 
further investigation, particularly as to its chemical rela- 
tions and medicinal powers. If it should prove to possess, in 
full, the useful properties of the plant, it may become a va- 
luable agent in the hands of the practitioner. 
ART. XXV1IL— REMARKS ON THE OINTMENT OF PRECIPITA- 
TED CARBONATE OF ZINC, AS A SUBSTITUTE FOR THE 
CERATUM Z1NCI CARBONATIS, U. S. P. 
By Thos. S. Wiegand. 
About a year since, having need to replenish my stock 
of prepared Carbonate of Zinc, an article was supplied, with 
which, on account of its colour, I was dissatisfied. Pre- 
vious to this time, a paper (published in the American 
Journal of Pharmacy for 1844, page 182,) which stated 
that a coloured sulphate of baryta was extensively substi- 
tuted for calamine, had attracted my attention : supposing 
the subject worth examining, I concluded to test the quality 
by chemical reagents ; the result of this examination was 
that there was no zinc present. 
Despairing of success in obtaining a pure calamine, I 
determined to prepare the carbonate artificially, which may 
be readily affected in the following manner: 
Take of crystallized sulphate of zinc, 1 lb. 
" carbonate of soda, u 
The salts are to be dissolved in separate portions of water, 
and the solutions mixed; when the precipitate shall have 
subsided, the supernatant liquor is to be drawn off, and the 
