[ 6x8 J

of pure tin, being melted together, the mixt was of a whitecolour without the least yellowness, rough on the surface,tolerably bright underneath, easy to break, of a broad leafytexture like the best regulus of antimony, in weight 2981.Beaten into powder and calcined under a muffle, with amoderate heat, for five hours, it appeared of a light greycolour, and Weighed 3283; so that it had gained in thecalcination above a tenth part of the weight of the mixt,or between a fifth and a sixth part of that of the tin. Thecalx was put into an aflay crucible, which was inclosed in alarger, and urged with a strong fire for two hours: thecover of the outer crucible, made of Sturbridge clay, re-mained sound; that of the inner one, made of clay andchalk, melted entirely, and lined the inside of the cruciblewith an opake dark-coloured glass. The powder, at thebottom, continued unmelted, and to the naked eye lookednearly of the same appearance as at first, but on viewing itwith a magnifying glass, several distinct particles of goldwere observed in it. A little of the powder was mixedwith about ten times its quantity of powdered flint glass,and exposed to a strong fire in a wind furnace for severalhours: the glass proved nearly transparent, uncoloured, aLittle cloudy, with grains of gold at the bottom.

Page j 14. Gold with sal microcosnicus .

Mr. Pott, in a curious dissertation on this remarkablesalt of urine, gives some experiments which seem to strewthat this salt has little or no action on gold. Ground withgold leaf, and then melted with a blow pipe on a coal, itforms a pearl-like mass, which in the air becomes a trans-parent slime or gelly : this melts again into the same ap-pearance as before, and on continuing the fusion, the goldseparates and rises to the surface in form of a massive leaf,

the