,[838] 
driven off by roafting, and then more perfectly by 
melting the refiduum in a ffrong fire into a glafs, 
whence it acquires a moff violently emetic power, 
which notwithffanding is foon totally destroyed by 
re-melting it with much common fulphur. 
But although this grofs external fulphur is not at 
all neceffary to the conftitution of the reguline, me- 
tallic part, an internal or metallic fulphur appears 
abfolutely requifite to the exigence of the regulus, as 
regulus j for when antimony is quite deprived of all 
its fulphur, by what is called the humid or dry cal- 
cination, it ceafes to be metallic or antimony. Thus 
antimony expofed to the ffrong concentrated rays of 
the fun, becomes an abfolutely inert calx, or caput 
mortuum, and can never be reduced to its original 
nature and form, but by the addition of fome ful- 
phureous body. The fame happens, when large 
quantities of nitre are deflagrated with antimony, till 
the fulphur is all burnt off, as in the common anti- 
monium diaphoreticum. 'Tis thus alfo in the hu- 
mid calcination, when ffrong fjpirit of vitriol is 
poured on the reguline mafs, which it tears abroad, 
and lets loofe the phlogifton ; for this calx likewife is 
not reducible to regulus but by fome fulphureous 
pabulum, in clofe contadt and fufion with it. The 
ffrong fulphureous fmell of the oil of vitriol, when 
forced off by diftillation, or the like, dilcovers the 
phlogiffon, and whence it came. Moreover this 
calx is intirely white, and will not in the leaft de- 
flagrate with l’alt-petre ; an argument of the abfence 
of any fulphureous matter. This calx however is foon 
alfo turned into a regulus by the addition of a pro- 
per fulphur, and then deflagrates with nitre as ufual. 
