352 Dr. Pearson’s Experiments and Obfervations 
were as white as fnow. The total mean lofs of weight, by 
thefe two calcinations, was then T 4 JL. 
exp. ii. 2000 grains of coarfely powdered antimony were 
calcined in an earthen difti, as in making Lile’s Powder, by 
conftantly raking them about for above three hours. During 
a great part of this time the veffel was red hot at the bottom ; 
and for the laft hour the fulphureous fumes had entirely ceafed. 
The calx thus produced was of a pale bluifh colour; it melted, 
in a low degree of heat, into an opaque, fcoria-like brittle mafs ; 
it yielded no hepatic air with marine acid ; it weighed 1409 
grains, or the antimony loft nearly 29 \ per cent. The pyro- 
meter in the veffel with the antimony during its calcination, 
was con trailed to the 6th degree of Wedgwood’s fcale. 
The fum therefore of the lofs of antimony and bone by cal- 
cination in this manner, feparately, was 37! per cent . Thefe 
two fubftances were in the next place calcined together in the 
fame manner in an open veffel, as above mentioned. 
exp. hi. 2000 grains of antimony from the fame parcel as 
that in the laft experiment, and an equal weight of hart’s 
horn (havings taken from the fame parcel as thofe were in 
Exp. 1. were calcined together in the fame manner that thefe 
fubftances had been feparately. During the firft quarter of an 
hour, the mixture fmoked, was black, fmelled ftrongly of 
fulphur, and felt loft. For half an hour more, the fmell of 
lulphur continued, the mixture turned brown, and the bone 
was reduced to a(hes. At the end of this time, not only the 
bottom of the veffel might be kept red hot without any figns 
of fufion ; but the fmell of fulphur, though weakly, conti- 
nued for half an hour more in a heat to keep a great part of 
the mixture red hot. At this time the fulphureous fmell rather 
fud ( denly difappeared, and could not be perceived, though a 
little 
