STRUCTURE OP WOOD, &C a 
107 
in the hand a sufficient quantity of the shavings, of a known Heat from 
weight. charcoal. 
The very small portions of the shavings which remain 
between the nippers are carefully preserved and weighed, at the 
dose of the experiments, to determine precisely how much of 
the wood has been consumed. 
An assistant keeps his eye constantly on the thermometer 
attached to the apparatus, aod announces the moment when the 
water in the calorimeter has attained a temperature as much 
higher than that of the room, as it was below it at the begin- 
ning of the operation ; and the fiame from the piece of wood 
then burning is immediately blown out. 
The remains of the shaving is laid aside, to be afterwards 
weighed with the other fragments. 
The water in the calorir^eter was then stirred, by shaking it, 
taking care to hold the instrument by its wooden frame, and 
the temperature of the water was minutely observed and set 
down in a register. 
An experiment of this kind usually occupies about 10 or 12 
minutes, according to the nature cf the wood, and the number 
of degrees to which the temperature of the calorimeter is raised. 
I made choice of the birch for my first experiments, because 
the texture of its wood is very firm and even, and burns with a 
yery regular flame. 
To give the details and their results in few words, I have 
placed them together in the subjoined table. 
The calorimeter, with the water it contained, was equal in 
capacity, as to heat, to 2781 grammes of water. 
Heat 
