44 ON TIN.- 



Facts and oU- bc imposctl' on by some apijcaiancc with which T am una€^# 



Sv;n-arioiis oil • ^ ^ it i i , /• • , • , i 



tinaiiditscom- fl^'^'iiicfi- 'le says that sulphurot or tin and cinnabar heated 

 pounds. together, yiyld mosaic gokl. A result so contrary to princi- 



pk's, appeared incredible ;. I repeated the experiment, and 

 found, that these two sniphurets heated, produced merely cina- 

 bar and sulphuret of tin ; the one volatilised, the other mould- 

 ed in tJie bottom of the retort. 



..yil these facts sufficiently acquaint us with what takes place 

 iu the operation of converting tin into mosaic gold. It would 

 bc useless to urge ihot the intervention of mercury is as super- 

 f1:ious in luis pi-epaia!i(jn, as in that of fuming muriate of tin, 

 as I have shewn, in 1801, in the "■Journal dc Fli^sique," 

 voL lii. 



Mosaic Gold and Acids. 



Sulphuret of tin is composed of metal 100, of sulphur 20. 

 Qf this Sage and Bergmann were assured : I also found the 

 same proportions. Muriatic acid readily acts upon this sulphu- 

 ret of tin at a mininnuti, sulphurated hydrogen, &c. But it 

 is a singular circumstance that the-same acid has not the least 

 influence upon mosaic gold ; it merely clears it of metallic 

 sulphuret, as has been remarked by Pelletier. 



Kitric acid, which likewise easily destroys sulphuret, has as 

 little power ovci" mosaic gold : a fact not less extraordinary, 

 ■when we recollect the facility with which tin and sulphur, 

 under other circumstances, are acted upon by nitric acid. 



To dissolve mosaic gold, aqua-regia must bc used, and it 

 must have a long and continued boiling. The result is a kind 

 i>i sulphate of tin at a maximum. It is decomposed by the 

 heat, and after drawing over oil of vitriol, a residuum is 

 obtained of spongy white oxide, which must bc washed to 

 cleanse it from acid. The edulcorating water contains not an 

 atom of tin; sulphureous hydrogen discovers nothing in it, un- 

 less it be atoms of mercury, when the mosaic gold of cpmmerce 

 has been used, arising from the small quantity of cinnabar some- 

 times found in it. 



One hundred gftiins of saltpetre, and fifty of mosaic gold^ 

 / heated gradually in a small retort, exploded with much vio- 

 lence, and hud nearly been attended with serious consequences 

 to inc. 



