METALLIC OXIDES. 
165 
fftore than half a line in thickness. The last layer contained Oxides of tin. 
the aurum musivum, which had undergone no change. This 
proves* that the aurum musivum, before it is reduced to the 
common sulphuret, passes through the intermediate degree j 
bat* as this last layer is very fine* it is evident* that the differ- 
ence of temperature which it requires to produce these two 
inferior layers* is very trifling ; and when the lire has been a 
little too strong, any traces of the intermediate layer are very 
seldom seen. 
The intermediate sulphuret of tin, digested with concentrated 
muriatic acid* produces sulphurated hydrogen* which, by de- 
grees* assumes a fine yellow* and becomes aurum musivum, 
which remains insoluble* and is obtained by filtering the liquor. 
This decomposition takes place very slowly, but even after 
some hours ©f digestion* the sulphurated hydrogen gas con- 
tinues to be disengaged* though still decreasing in quantity. 
I have made several attempts to analyse the aurum musivum* 
but I hav® not been able to procure this combination in a suffi- 
ciently pure state* and perfectly separated from the intermediate 
sulphuret. A portion of the common aurum musivum, which 
did not contain cinnabar* a thing this preparation is frequently 
adulterated with* in consequence of the mode in which it is 
prepared* was decomposed by means of the nitro-muriatic 
acid. This liquid, precipitated with the muriate of barytes, 
produced three grammes of aurum musivum, 7'46'3 grs. of sul- 
phate of barytes, ignited in the fire, which correspond with 103 
grs. of sulphur. Therefore it follows, that 100 parts of tin 
had been combined with 52 3 parts of sulphur. This is not 
exactly double what the tin contains in the common sulphuret* 
but the difference is not very considerable* and* with the con- 
firmation which the doctrine of multiple proper tionshas already 
gained, I think we may determine, with some degree of cer- 
tainty, that aurum musivum contains twice as much sulphur 
with the same quantity of metal as the common sulphuret. 
It is very evident, that oxigen is not necessary to the consti- 
tution of aurum musiviura, because the latter is produced by 
the action of muriatic acid on the intermediate sulphuret ; on 
which occasion no other oxidation can be imagined, except that 
which produces a muriate of tin. 
As to the nomenclature of these three degrees of sulphurets, 
it 
