100 
STRUCTURE OF WOOD, &C. 
Moisture, &c. in their natural state gained 1 '33 grammes in weight; while 
in wood. those that had been scorched gained only 07 grammes. 
A similar experiment, upon shavings of the cherry tree, some 
in their natural state, and others scorched, was productive of 
the same result. 
Whence we conclude, that wood in its natural state attracts 
the moisture of the air more copiously than it does after 
having been subjected to the first degree of carbonisation. 
From similar experiments upon wood and charcoal, I find 
that dry wood attracts humidity more powerfully than dry 
charcoal. 
It would be worth ascertaining, whether wood is not also 
more powerfully attractive of gas than charcoal ; but as I have 
not time to enter upon this particular inquiry, I can only re- 
commend it to those whose inclinations may lead that way. 
Leaving, therefore, this subject untouched, I must, without any 
farther circumerration, pursue the original object I had in view 
in these disquisitions upon wood, viz. to endeavour to become 
acquainted with those inflammable substances, which burn on 
setting Are to a piece of wood under a calorimeter. 
Section VI. 
Of the Quantities of Charcoal to he oltained from different 
Kinds of Wood. 
diarcoaJ 011 having discovered that pieces of wood, more or less thick, 
may be perfectly carbonised in glass vases, with thin tops, 
closely covered, and exposed for two or three days to a mode- 
rate heat in a stove, I adopted this method in all my experi- 
ments on the carbonisation of wood. 
The glass vases which I make use of, are what the chemists 
call proofs, with feet : they are small cylindric vessels, about 
an inch and a half in diameter, and six inches in height ; the 
covers consist of glass plates, about two inches in diameter, and 
from two to three lines in thickness, neatly ground with very 
fine emery, well diluted with water, on a large glass slab $ and 
the edges of the vases being ground with the same exactness, 
they became hermetically closed by the covers, so as to preclude 
every access of the air, especially if the edges of the vases, and 
the whole surface of the covers, be well rubbed with black-lead. 
The elastic fluids, in escaping from the interior of the vases, 
occasionally 
