( iH ) 
file San’s breaking and melting together into a Sodder 
(if I may fo fpeakj fome of _thefe fmall Criftals, by de- 
grees as the fulphurous part leaves them ^ it not being 
ftrong enough to melt them all down together in one 
intire Mafs. 
Of Lead. 
I took Lead, and held it in fafionupon Charcoal in the • 
Focus of theGlafs: it all wafted away in abundance of 
Fumes. 
I expofed the like quantity of Lead upon a Sfone to the 
Focus, v; here it caft forth great quantities of fumes, and 
by little and little changed into a fluid Liquor like Oil or 
melted Rofin. This Liquor, as it grew cold, fix’d into 
Glafs^ which has this peculhrto it felf, that it is difpofed 
into Plates like Venetian Talk, and that it is flabby, foft 
to the touch, tranfparent, and in fome parts of a -green- 
ifh or reddiQi Yellow. 
In continuing this matter in the Focus, it fpxad upon ^ 
the Stone like Varnifti ^ and at laft penetrating it, help’d j 
to melt it. ^ 
I placed this talfcy Earth in the Focus upon Charcoal.* ^ 
It melted, and in a litrietime after reaflumed the form of 
melted Lead. I withdrew it from the Focus, and having ^ ' 
let it cool, found it nothing different from Lead. 
Thefe Experiments (how, that there if in Lead, aS well 
as the other imperfetft Metals, a (ulphurous part, that is 
eafily feparated by common Fire or the heat of theSnn • 
and that this Metal has for its Bafis a foliated or talky 
Earth 
Of 
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