Action of Water wpon Mercuric Sulphate. 599 
allowed to evaporate spontaneously in vacuo, neutral mercuric 
sulphate crystallizes out. 
It is stated in the books, that the crystals formed by evaporat- 
ing an acid solution of mercuric sulphate attract moisture from the 
air. The statement is incorrect ; the crystals, when freed from 
excess of acid, are permanent in the air. 
It is stated that one part of basic mercuric sulphate dissolves 
in 3,000 parts of cold water. I find that a litre of water at 16° 
cent. (60°8° Fahr.) dissolves 0°023 of the salt (dried at 100° cent.) 
or 1 part in 43,478 parts of water; that is 2°3 parts of the salt 
are soluble in 100,000 parts of water. The freshly precipitated 
salt dissolves to the extent of 0:031 gramm, per litre of water 
at 16° C=1 part in 32,258 of water. 
The only acid mercury salts referred to in the books, are the 
salt which I have shown has no existence, and an acid selenite 
of mercury. The results of experiments which I am making at 
present lead me to infer that there is no acid mercuric selenite. 
The tendency of neutral mercury salts is to combine with alkaline 
bodies, not with acids. 
Soren. Proc. R.D.S. Vou. m, Pr. vir, ‘ 25s 
