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If one melts Tin upon a Coppel in the Focus of the 
Glafs, ic fumes very much, and ifs fnrface is cover’d with 
a white rarified Calx 5 on which by little and little arife» 
a tufc, or heap ot (harp, needle-like, tranfparent, criftal- 
line Particles, confifting of an infinite number of fmall 
Points. 
If one continues to hold this Mafs in the Focus upon 
the Stone, thefe Criftals at lenghth leave off fuming, 
and remain fixt, while the Stone meit| and vitrifies. 
I took Calx ot Tin, which is Tin reduced to a grey 
Powder by means of Fire, that has taken a.vay by Calci- 
nation great part of its oily Subfiance, and expofed k 
on a Coppel to the Focus, where it fumed again very 
much, and was reduced into (harp chriftalline Particles 
confifting of other fmall Points. 
In re-expofing thefe chryfialline Particles to the Focus 
upon Charcoal, they melted very cafily, and took again 
the Form of Tin 5 the Coal having furnifiicd them with 
the fnlphurous part that the Fire had before taken away. 
Every body knows, that if one adds any Fat, or the like 
inflammable Matter, to the Calx of Tin when red-hot in 
the Crucible, it reaffumes immediately the form of 
Tin. 
Thefe Experiments fhow, that Tin contains a Sulphur 
that is very eafily feparated, fince common Fire can do it 
fo readily 5 and that this Metal calcined, or deprived of 
its Sulphur, is eafily faturated again with it from the oily 
part of any inflammable Matter whatfoever. 
It proves alfo, that the metallick Earth which h the 
Bafis of Tin, is a CrifiiUine Earth, very diflicuk to be 
melted 5 fince common Fire cannot vitrify this Metal by 
it felf, and that the heat of the Sun, in the Focus of 
this large Burning-Glafs of the Palace-Royal, cannot per- 
fe(fily melt the Calx into which this Metal is reduced. We 
may prefume that the Crifiallifation, or reducing of this 
Metal into lharp-pointed Particles,, proceeds from the force 
