(321) 
of opinion, 'tis not perfectly known , I (hall here declare, ts briefly as 
I can. 
Having reducM the Ore into fmall ftones,they calcine itfirfl: in a revet- * 
berating Oven, yet with a moderate fuv , for fear of fufion, and driving 
away into the air part of thetreafure, the volatile puts being by nature 
not perfectly mixt per minima with the fix t, as they afterwards come to 
be by induftry and Art, And I have heard fome of the more intelligent 
Mineraliftsfay , that they judge their metallick labors and operations, to 
be many times not fo much a reaping of (liver ready made, as a kind of 
artificial compounding H and bettering of that , which nature had left 
difpers'd and imperfect. This Calcination- ferves chiefly to free the Mine- 
ral from many infirmities, that hinder the operation of the Quick-filver - 
and it ferves alfo to difcover i by the color of the fumes it yields, what 
c^rrofive mixture chiefly abounds in it, befides that it renders the one more 
tradable and plyant under the Mill-done, which is to reduce it to a fmai 
flower before the application of the Mercury. This is chiefly obferved 
in thofe Silver-veins, that are of fo hard and dry complexion , yet thofe 
which areufually rnorefoft, abounding in oleaginous Sulphures , before 
burning are firft ground into powder in fuch Mills as I have often feen in 
Glafs-houfes : and then they receive a gentle calcination 3 the Mineralift 
mingling therewith Ingredients futable to the peccant humour , if I may 
fo fpeak, of the Ore. As if,(e. g.)the mettal be fulphureous and and- 
monial, Ruft and drofs of Iron is found to be an excellent cure of this 
diftemper : if Martial, and abounding in Iron, then Sulphur and Antimony 
reduced to powder, is ufed as a convenient remedy for that difeafe. 
Sulphur hath a particular force, as I have found by experiment , tofoften 
and difToive Iron. But not only in this operation of Calcining, but alfo 
in applying the Quick-filver, there are fo many different cafes, in which 
different remedies are to be ufed, as there are Silver veins of feveral con- 
(titutions \ of which elfewhere. 
The Ore being ground, calcin'd, and curioufly fifted , they ' divide it 
in feveral heaps, and then by leffer EfTays, they find out how much filver 
is contained in every heap- where Ms very ordinary to find only 6. ounces in 
loo. pounds- fometimes 12^ but if it yield 18. 'tis efteem'd a very rich 
vein: yet fometimes there are great Maffes found all of pure filver, 
which is call'd F*V£/>mettaI. 
Having difcovered the quantity of filver contain'd in erch heap, thea 
proportionably they befprinkle them with quick-filver, and that not all 
at once, but at feveral times, ftirring the Ore up and down. Then ac- 
cording to the difeafes already difcovered in the Vein by the fumes in the 
calcination^ or according to any new fyrrp torn?, appearing in the opera- 
tion of the quick-filver , convenient remedies are fpply'd, if ( e.g.) 
the Mtrcury give fignes of being tccado (as they call it) i.e. ifitrppear 
