[ 841 ] 
this tm&ure, evaporated to an extra#, gives off the 
fulphureous tinfture to rectified fpirit of wine : but, 
if this fame glafs is thus feveral times treated with 
frefh diftilled vinegar, or its concentrated fpirit, at 
length it neither gives it any tindture, or emetic power, 
but remains a dead, dark-coloured, inert mafs, all 
the fulphur being extracted, and the glafs reduced to 
a mere calx. Befides, even glafs of antimony will 
in fome meafure deflagrate with nitre ; which (hews, 
that it ftill retains fome of the fulphureous princi- 
ple ; and, in order to render it mild and innoxious, 
J tis necefiary to corre# it by burning off the fulphur 
of the glafs with nitre, or by the burning-glafs : 
which is in truth the deffru#ion of the metallic con- 
fidence in the glafs. 
But it is a much more difficult thing to prove the 
exiftence of the reguline fpicula in the glafs of anti- 
mony, in the very form of which I feem, in a 
great meafure, to have placed its emetic quality ; and 
yet glafs of antimony is the mod violent of all its 
preparations. I confefs, the fpicula, or needles, by 
no means appear in the glafs ; but they really do fo, 
when the glafs is digefted, and diffolved in wine, by 
laying a drop of the liquor on a plate of glafs, and 
then viewing it through a microfcope. And fur- 
ther, vitrum antimonii, reduced to a regulus with a 
little common fulphur, appears of a needle-like 
ftriated form. And incinerated antimony, when 
melted with too flack a fire, often appears a mafs of 
half-ftriated regulus, and half glafs, fo little is the 
difference. The falts in common glafs do not ap- 
pear, though they are unqueftionably there, and 
fometimes fo loofely combined with the vitrefcible 
7 O earth. 
