408 
Tin. 
paration of mercury ; although not a particle enters into 
the composition of aurum mosaicum, which consists of 
2-3 tin and 1-3 sulphur. 
A good coloured aurum mosaicum may be thus pro- 
duced. Saturate 8 ounces of melted tin with sulphur : 
pound it ; mix it accurately with 5 ounces more of sul- 
phur, and 4 ounces of sal-ammoniac : calcine it with the 
precautions above mentioned. (Woolf.) 
The apparatus recommended by Woolf is the following. 
Take a large black lead crucible, number 60 ; bore a 
round hole in its bottom about three inches diameter, and 
saw off an inch of its upper edge. If it has a lip, get a 
round piece of burnt clay of an inch thick or rather more, 
to fit exactly into this edge. The composition used for 
making paving tiles, answers very well for this purpose. 
In order to make use of this apparatus, lit the round piece 
of burnt clay to the inner edge of the crucible, by means 
of some loam softened with glue, and dry it slowly. 
Then turn it upside down, and lay it in a proper furnace 
on two iron bars. The mixture for the aurum mosai- 
cum is to be put in through the round hole at top, and 
then covered with an aludel (a wide pipe or tube open at 
both ends) and luted. This serves to collect the flours 
and sublimate that rises. The fire is to be made under 
and all round the crucible. 1 lib. troy of aurum musivum 
may be thus made at a time. The operation, which 
takes about eight hours, cannot fail, if the fire be of suffi- 
cient strength and of an equal degree from the top to the 
bottom of the crucible. 
Mr. Woolf observes, that the sublimed muriat of tin 
produced in this process, is very far superior as a mor- 
dant to any of the solutions used by the dyers. 
Mr. Proust has recorded 21 experiments on this sub- 
ject in the 1 3th vol. of the Annales de Chymic. These 
experiments lead to the conclusion that aurum musivum 
