E54 ; EFFECTS of HEAT 
. dom; and I find that, in the open fire, horn yields a charcoal 
equal to 20 per cent. of the original weight. But more expe- 
ximents muft be made on this fubjeé. 
Anoruer caufe of the lofs of weight, lay undoubtedly in the 
excefs of heat employed in moft of them, to remove the cradle 
from the barrel. With inflammable fubftances, no air-tube 
was ufed, and the heats being low, the air lodged in inter- 
ftices had been fufficient to fecure the barrels from deftruction, 
by the expanfion of the liquid metal. In this view, likewife, I 
often ufed lead, whofe expanfion in fuch low heats, I expected 
to be lefs than that of the fufible metal. And the lead requir- 
ing to melt it, a heat very near to that of rednefs, the fubject 
of experiment was thus, on removing the cradle, expofed in 
freedom to a temperature which was comparatively high. But, 
obferving that a great lofs was thus occafioned, I returned to 
the ufe of the fufible metal, together with my former method 
of melting it, by plunging the barrel, when removed from the 
furnace, into a folution of muriate of lime, by which it could 
only receive a heat of 250° of FAHRENHEIT. 
Tue effect was remarkable, in the few experiments tried in 
this way. The horn did not, as in the other experiments, 
change to a hard black fubftance, but acquired a femifluid and 
vifcid confiftency, with a yellow-red colour, and a very offen- 
five fmell. This fhews, that the fubftances which here occa- 
fioned both the colour and fmell of the refults, had been dri- 
ven off in the other experiments, by the too great heat applied 
to the fubftance, when free from compreffion. 
I rounp that the’ organization of animal fubftance was en- 
tirely obliterated by a flight action of heat, but that a ftronger 
heat was required to perform the entire fufion of vegetable. 
matter. This, however, was accomplifhed; and in feveral 
experiments, pieces of wood were changed to a jet-black and 
inflammable fubftance, generally very porous, in which no 
trace 
