404 On the Heat developed in Combustion 



a method, by steeping thin chips of wood in some in- 

 flammable 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 accu- 

 rately how much heat this quantity of wax should have 

 given in its combustion, if the chips thus prepared had 

 been burned properly under the calorimeter, I should 

 certainly have discovered how much heat the charcoal 

 would have furnished ; but the experiment did not suc- 

 ceed. 



The wax was entirely burned, and the chip of wood 

 became very red ; but it was not burned, at least not en- 

 tirely, nor in such a way as to give me the least hope of 

 being able to derive any advantage from my experi- 

 ment ; and I did not succeed any better by steeping my 

 chips of charcoal in melted tallow, in oil, alcohol, sul- 

 phuric ether, naphtha, essential oil of turpentine, in a 

 solution of gum-arabic, and in that of sugar. I have 

 also tried colophon, but without more success. 



I have made several experiments in order to deter- 

 mine directly the quantity of heat which is developed 

 in the combustion of considerable masses of charcoal 

 (80 grammes) burned in a small stove, under a calorime- 

 ter of a large size, which I procured at Paris four years 

 ago, 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, I found that the ex- 

 periments of Crawford were better than mine ; and as 



