( ) 
That if one reftores to this Calx a Sulphur, by expo- 
fing it again to the Focus upon Charcoal, it reaffumes 
immediately its metallick Brightnefs and Fluidity, and 
becomes Quick filver. 
I cannot tell whether this light Earth, that remains 
upon the Stone after the evaporation ot the Calx of the 
Mercury, be a part of the Earth ol the Mercury more 
cxadly deprived of its' Oil, and confequcntly more fixt 
and proper for Vitrification 5 or whether it may not 
be fbme Matter foreign to the Mercury, that fixes 1 
it felf, and remains behind at its Evaporation. But 
this I (hall examine more particularly hereafter. 
The Refult of all thefe Experiments is, that thefe 
four Metals which we call imperfe^^, viz. Iron, Cop- 
per, Tin, and Lead, are compofed of a fulphur or oily 
Subftance, and of a metallick Earth capable of Vitrifica- 
cation. 
That from this Sulphur proceeds the Opacity, Bright- 
nefs, and Malleability of a Metal. 
' That this metallick Sulphur does not appear at all 
different from the Oil of Vegetables or Animals. 
That it is the fame in Mercury as in the four im- 
perfeft Metals. 
That thefe four Metals have for their Bafis an i 
Earth fufceptible of Vitrification. 
That this Earth is different in every one of thefe 
four Metals 5 in that it vitrifies differently in each of 
them. 
And that on this difference in Vitrifying depends the r 
difference of Metals. 
It remains chat I fhould examine more particularly 
the Nature of thefe Earths or metallick Vitrifications^ m 
to know if 'any other Principles or Subftances maybe ,:j| 
fcperated from them: But this I (hall endeavour to do 
hereafter, in profecuting the Analyfis ot thefe Metals as 
tW as pofTiblc. 
