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LXI.—ON THE ACTION OF WATER UPON. MERCURIC 
SULPHATE, sy CHARLES A. CAMERON, ».p., F.R.€.8.1. 
[Read June 21st, 1880. ] 
In Berzelius’ Treatise on Chemistry, and in all its editions in 
German and French, it is stated that the action of water upon 
mercuric sulphate resolves it into an insoluble sub-salt, and an 
acid soluble salt. The latter, it is stated, may be obtained by 
evaporating its solution, until crystals begin to form. These 
erystals are described as white needles, which attract moisture 
from the air, and are precipitated out of solution on the addition 
of concentrated acid. This statement, in reference to the action 
of water upon neutral mercuric sulphate, appears to have been 
copied into most works on chemistry of later date. In Fowne’s 
Manual of Chemistry, 12th edition, 1877, page 424, it is stated 
that— 
“ Water decomposes the (mercuric) sulphate, dissolving out an acid 
salt, and leaving an insoluble yellow basic compound, formerly called 
turpith or turbeth mineral containing, according to Kane’s analysis, 
HgSO,, 2 HgO, or 3 HgO, SO,.” 
In Brande and Taylor’s, Tidy’s and other modern works on 
chemistry, reference is made to a soluble acid mercuric sulphate. 
In Watt’s Dictionary of Chemistry, the formula HgO, 380, is 
assigned to this salt. This statement assumes that the action of 
water upon neutral mercuric sulphate is to resolve it into trimer- 
euric sulphateand mercuric trisulphate—4 HgSO, = HgSO,(Hg0), 
+HeSO, (SO,),. The formula assigned to the acid mercuric sul- 
phate is a very unusual one. The salt is stated in Watt’s Dic- 
tionary to be procurable by evaporating the liquid which remains 
when the basic salt produced by the action of water upon mer- 
curic sulphate is separated. The results of my experiments show 
that an acid salt cannot be obtained in this manner. 
EXPERIMENTS. 
Neutral mercuric sulphate was treated with water. The basic 
salt thereby formed was separated from the liquid by filtration, 
and the liquid evaporated until a pellicle made its appearance 
