298 Researches upon the Heat developed 
wood made into charcoal, with the same facility that we burn 
thin pieces of dry wood, the investigation in question would 
not be attended with difficulty ; but the charcoal cannot be 
burned in this manner. We can light a piece of charcoal 
very well, and if it be very thin it continues to burn until 
it is entirely consumed; but the combustion is so slow, and 
furnishes so little heat, that it would require several hours 
to heat the calorimeter sufficiently to give an appreciable 
result; and for this single reason the result could not but 
be extremely uncertain. 
I have long endeavoured, but without success, to find a 
method, by steeping thin chips of wood in some inflamma- 
ble liquid, to burn the charcoal more rapidly. 
Some chips of wood of a known weight, perfectly dried 
and strongly heated, were plunged into white wax, melted 
and very hot, and the chips when taken out and cooled were 
again weighed. 
Their augmentation in weight gave me the quantity of 
wax which they had imbibed; and as I knew accurately 
how much heat this quantity of wax should have givenin 
its combustion, if the chips thus prepared had been burned 
properly under the calorimeter, I should certainly have dis- 
covered how much heat the charcoal would have furnished ; 
but the experiment did not succeed. 
The wax was entirely burnt, and the chip of wood be- 
came very red ; but it was not burnt, at least not entirely, 
nor in such a way as to give me the least hope of being 
able to derive any advantage from my experiment; and I 
did not succeed any better by steeping my chips of char- 
coal in melted tallow, in oil, alcohol, sulphuric ether, 
naphtha, esseatial oil of turpentine, in a solution of gum 
arabic, and in that of sugar. IT have also tried colophon, 
but without more success. 
I have made several experiments in order to determine 
directly the quantity of heat which is developed in the 
combustion of considerable masses of charcoal (80 grammes) 
burnt in a small stove, under a calorimeter of a large size, 
which I procured at Paris four years age, and which I have 
still in my laboratory; but the results of these experiments 
have been too variable to satisfy myself. 
After all the care which I took, [ found that the ex- 
periments of Crawford were better than mine: and as they 
furnished more heat than I could find, I have not hesitated 
to adopt their results, instead of relying upon my own, 
§ X. Quan- 
