MISCELLANY. 
263 
pentine, it is easily changed by agitation into an emulsion, and in time 
swims upon the surface like cream upon milk ; after this it acts like a 
varnish. But it requires much less of the oil of turpentine to dissolve it, 
than when it has not been softened by the ammonia. Ann. des Mines, 
On Schweinfurt Green, by M. Ehrmann, {Ann. der Pharm.) — Triturate 
100 parts of basic acetate of copper with sufficient water at 50°, to form 
a liquid pap ; mix with this emulsion a solution of eight parts of arsenious 
acid in 100 of boiling water; the whole to be kept boiling. Sometimes 
it is necessary to add a little vinegar, that the color may be fine and in a 
crystalline state. The supernatant liquid is acid, and contains likewise 
some oxide of copper. This liquid may be employed with advantage in 
subsequent operations, to dissolve the arsenious acid. It likewise facili- 
tates the solution of the acid in the water to add a little carbonate of 
potassa. 
Schweinfurt green may also be obtained by mixing together two boil- 
ing solutions, the one of the neutral acetate of copper, and the other of 
arsenious acid. When thus prepared, it receives the name of Vienna 
green. 
These two colors are identical, and are composed of — 
Oxide of copper, 0.31243 4 at. 
Arsenious acid, 0.58620 3 " 
Acetic acid, 0.10135 1" 
Their formula is CuC 4 H 6 3 -r-3Cu As, 
This substance is insoluble in water ; but the acids, the same as the 
acetic acid, dissolve by decomposing it. The alkalies likewise decom- 
pose it, and if boiled upon it, the copper is left in the state of protoxide, 
and an alkaline arsenite is formed. Ann. des Mines. 
On the Hydrated Peroxide of Iron, as an Antidote for Arsenic, by Robert 
B. Hall, M. D., (Princess Anne County, August 6, 1838.) — The 
hydrated peroxide of iron has, for some time past, been engaging 
the attention of the medical world as an antidote for arsenious 
acid. Much contrariety of opinion exists upon the subject, and while 
many of the most prominent members of the medical corps exhibit 
a spirit of scepticism with regard to its anti-arsenical virtues, still, a host 
of names, " not unknown to fame," are disposed to consider its properties 
in this point as specifical. The object of this communication is to sum 
up, in a concise manner, the most positive testimony in favor of its pro- 
perties as a counter-poison, which my limited opportunities have enabled 
me to collect, and at once submit it to the medical world, together with 
a few experiments of my own, in order that some of your numerous 
readers, who feel interested in the subject, may, by comparing expe- 
riments, or otherwise, incontrovertibly establish an important point in 
toxicology. 
