164 
METALLIC OXIDE*. 
Oxides of tin. phur, would acquire the characters of the most perfect aurum 
musivum. On taking it out of the ball, I mixed a fresh quan- 
tity of pulverized sulphur, and heated it in the same ball again 5 
but it received no addition of weight. On a repetition of the 
experiment, the result was the same. In these experiments 
100 p. of suiphuret of tin absorbed 11 p. of sulphur, in order 
to produce a species of aurum musivum, which nevertheless 
differed from the common sort, in its colour being less brilliant, 
and more inclining to grey. But these 11 p. of sulphur are, 
with a very slight difference, half as much as the suiphuret 
contained before 3 and we have here an example of sulphura- 
lion, which contains 1 \ as much sulphur as the preceding one. 
I do not yet know any other example of this multiplier (1 j) 
in the sulphurets. I made several vain attempts to combine this 
sulphuretwith more sulphur by heat, and that proved to me still 
more, that the body I had obtained was a degree of the sui- 
phuret of tin, of which no mention has been made by che- 
mical authors. This degree of sulphuration is composed in the 
following manner : 
Tin ... . 71-8 100 000 
Sulphur . . 28 2 ..... 40 851 
Aurum musivum, or mosaic gold. It is very difficult to say 
what circumstance most principally contributes to the forma- 
tion of the mosaic gold in the common manner of preparing it 3 
and it is very difficult to obtain a mosaic gold in this manner 
perfectly saturated wdth sulphur, and deprived of all foreign 
matters. We cannot consider any other aurum musivum as 
pure, except that which has been sublimed in bright yellow- 
crystals during the operation 3 but of this the quantity is usually 
very small. If we endeavour to sublime aurum musivumf 
which has already been prepared, it is decomposed, and the sub 
phur is obtained, and the usual suiphuret remains. A large piece) 
of this aurum musivum was slowly decomposed in a glass reJ 
ton by a moderate heat, which was not sufficiently strong : 
melt it 3 and when the mass was half decomposed, I took th< 
retort from the fire. I found in the remaining mass threj 
different layers. The first was porous, grey, and metallic — 3 
was the usual suiphuret. The second, which was less porous 
and of a greyish yellow, consisted of the intermediate sulphurej i 
which I have described. This layer was very fine, and of nc 
