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and it is alfo known to condud eledricity very im- 
perfedly. Iron foon turns to ruff ; and its conducing 
power I found to be very fmall, in companion with 
that of copper, or the more perfed metals. If, 
therefore, in making charcoal, a degree of heat be 
applied greater than is neceffary to calcine or revivify 
a metal, we may perhaps conclude, that the condud- 
ing power of the charcoal will be fuperior to that of 
the metal. As it may be poffible to give charcoal, 
when cut off from any communication with the ex- 
ternal air, a greater degree of heat than filver or gold 
would bear, without being diffipated in vapour; it 
may even be poffible to make charcoal that fhall 
condud eledricity better than thofe moft perfed 
metals. 
Had there been any phlogiflon in water, I fhould 
have concluded, that there had been no conduding 
power in nature, but in confequence of fome union 
of this principle with fome bafe. In this, metals 
and charcoal exadly agree. WJiile they have the 
phlogiffon, they condud ; when deprived of it, they 
will not condud. 
I believe, however, that all vegetable, or animal 
fubffances, that contain phlogiflon may be reduced 
to a coal ; and if the heat applied in the procefs be 
fufficient, that coal will condud eledricity. Flefh, 
glue, bones, and other parts of an animal body, make 
good conduding charcoal. 
The only approach, or feeming approach, I ever 
made towards retaining more phlogiflon than ufual, 
in wood reduced to a coal, was by the flownefs of 
the procefs. For I always found that, if the heat 
was applied very gradually, lei's volatile phlogiflon, 
i. e. lefs 
