“192 Miscellanies. 
14. Purple powder of Cassius.—M. Buison states that in prepar- 
ing this substance, he found that the solution of gold always contains 
the same muriate, though it may be mixed with more or less acid; 
but he observes, that the solution of tin, even when well prepared, 
contains two different muriates and itis upon their co-existence, with- 
in certain limits, that he conceives the goodness of the solution to be 
owing. The experiments upon which this opinion are founded are the 
following. 
1st. The solution of proto-muriate of tin, as neutral as possible 
when mixed with a solution of gold, gives a maroon, brown, blue, 
green, or metallic precipitate, according to its concentration and pro- 
portion, but the color is never purple. 
. Pure per-muriate of tin, whether acid or not, produces n0 
change in the same solution of gold, whatever be the proportions ell- 
ployed. 
3d. A mixture of one part of proto-muriate nearly neutral, and two 
parts of per-muriate of tin, with one part of muriate of gold, instantly 
occasions a fine purple color. Founded on these facts, M. Buison gives 
the following process for obtaining the purple powder : ‘ 
th. Dissolve about 15 grains of granulated tin, in muriatic acid, 
either with or without heat, taking care that the solution is neutral. 
5th. Prepare a solution of per-muriate of tin by dissolving about» 
30 grains of tin in a sufficient quantity of aqua-regia, composed of 
three parts of nitric acid, and one part of muriatic acid; taking cat 
that the solution is neutral, and free from proto-muriate which 18 
determined by its giving no precipitate with a solution of gold. 
6th. To prepare the solution of gold, dissolve about 108 grains of 
gold in aqua-regia, composed of one part of nitric acid and six paris 
of muriatic acid ; the solution should be nearly or quite neutral. 
Dilute the solution of gold, so that a pint of it contains about 1 
grains of the metal. Pour in the per-muriate, till the required tint 
is produced, remembering that the proto-muriate causes a brow? an 
the per-muriate a violet color, and intermediate proportions give 
Wash the precipitate as quickly as possible, that no action may ” 
place between the salts of tin and the precipitate, which alters its ©” 
or. The purple powder of a fine tint yielded by analysis ; 
Metallic Gold, é : ss i" es g 28.5 
Peroxide of tin, - : a . . r - 66.9 
Chlorine, * : ; 7 . : ‘ 5.3 
99.6 
Loss, 4 
Nt ae 
100.0 
(Jour. de Pharmacie, October, 1830.)—Idem 
i 
