JWMiscellanies. 199 
ment to the other salts of that metal, also uses the same solution. 
It very much surpasses the proto-muriate, and is always successful, 
whether used in a weak or concentrated state. When proto-nitrate 
of mercury is poured into a solution of gold, according to Fischer, 
a blue grey precipitate is obtained quite in analogy with the purple 
of Cassius. It is composed of deutoxide of mercury and of the sub- 
oxide of gold, and is not decomposed by muriatic acid; that sub- 
stance only dissolves a little mercury, and makes the color of the 
remaining precipitate pass to a clear grey-white.—Idem. 
3. On the Manufacture of Sulphuric Ether.—(C. Wittstock.) 
The remark of MM. Fourcroy and Vauquelin that the sulphuric. 
acid employed in the fabrication of ether undergoes very little 
change, led to the conclusion that ether would be formed as long as 
there was a fresh supply of alcohol to the acid. This supposition 
was confirmed by the experiments of M. Gay Lussac ; and since 
then, the fabrication of ether has been considerably improved by 
MM. Boullay, Geiser and others. I have for some time employed the 
following method; and as I am disposed to consider it more simple 
and less expensive than any other, a short description of it may 
perhaps be acceptable to the reader. 
A mixture of nine parts of sulphuric acid (sp. gr. 1.84—1.85) and_ 
five parts of alcohol (sp. gr. 0.835) are put into a green glass retort 
of one foot in diameter, with a glass tube inserted at its upper part. 
This tube is 4 lines in diameter, and bent at a right angle; the 
shorter arm, which, at its extremity, is only one line in diameter, is 
plunged one inch deep in the mixture; the longer arm, of about 
three or four feet of length, with a cock near its further end, leads 
into a bottle with alcohol. ‘The receiver consists of a refrigerator, 
viz: a wooden tube, filled with water, by which the distilled ether 
is kept cool, and two copper vessels, the one within the other, so that 
there is a distance of about 2 inches between their sides. ‘The neck 
of the retort leads into the intermediate space between the two cop- 
per vessels, which is thus filled with the distilled liquid, and from 
which the liquid may flow off by any other tube. The apparatus is 
used in the following manner :—When the mixture is boiling, the 
cock of the glass tube is opened and the supply thus kept up so 
that the quantity of liquid in the retort remains always the same ; 
this is continued until eight times the original quantity of alcohol has 
been used, which will be the case in about 20 hours, if the original 
