400 
Tan * 
per requires a complicated action, to which probably theT 
metallic tin present contributes. [2 Aikin y 427. 
It has been proposed to whiten copper, brass, and iron, 
in this manner by means of silver, or of zinc ; but I do 
not know of any decisive experiment to this purpose. 
The proposal is at least very plausible. 
Aurum Mu swum or Mosaicum . See 61 Phil. Trans. 
114. 13 Ann de Chimie, 280. 
I copy the following account of this substance from 
,^ikin, to which, at the expence of some tautalogy, I 
shall add my own notes. 
“ A beautiful golden- coloured species of sulphuret of 
tin has long been known in the arts, under the name of 
Aurum Musivum or Mosaicum , ( Mosaic Gold J. It is 
in the form of a scaly mass, sometimes crystallized in 
six-sided plates, very soft and glossy to the touch, readi- 
ly rubbed down between the lingers, and when the colour 
is brought out by a little friction, having a line golden 
metallic lustre. It is still prepared in pretty large quan- 
tities by some artists, and is supposed to be used princi- 
pally in artificial bronzing and other ornamental purposes. 
It was formerly employed in medicine. A great num- 
ber of receipts have been given for preparing it, most of 
which succeed nearly equally well, provided the same at- 
tention to management of the heat, See. be observed. It is 
also interesting to experimental chemistry, and its pro- 
perties have been examined by several excellent chemists, 
among whom may be enumerated Mr. Woolfe, the 
Marquis de Bullion, and M. de Pelletier. 
The old process for aurum musivum, and which is 
one of the best, is the following ; as contained in the Lon- 
don Dispensatory. 
Take 12 oz. of tin, 7 oz. of flowers of sulphur ; sal 
ammoniac and quicksilver, of each 6 oz. melt the tin by j 
