ON THE HEAT DEVELOPED IN COMBUSTION. 105 



together. As they still retained their original figure of sha- 

 vings, though reduced to a very small bulk, this appeared to 

 me a demonstrative proof, that the shavings, whence they 

 arose, had not been burned by a common fire. For this rea- 

 son, and also on account of their extraordinary colour, ap- 

 proaching very near that of the wood in its natural state, I 

 preserved them, to show them to the class. They weighed 

 only 0*04 of a gr. ; and as the shavings, of which they were 

 the remains, weighed 2*987 gr. on coming out of the hands 

 of the joiner, these ashes make only one and one third per^ 

 cent of the weight of the wood. 



The third parcel of shavings, which had been placed in a ' 



narrow glass vessel, had not disappeared, but the wood was 

 converted into perfect charcoal. I have the honour to pre- 

 sent it to the class, in the same vessel in which it was charred. 



As the three parcels of shavings were of the same wood, Reasonings on 

 and equal in weight ; as' they were exposed together to the them - 

 same degree of heat, and for the same time ; and as the two 

 portions, that were placed so as to facilitate the escape of the 

 carbonic acid gas arising from their decomposition, disap- 

 peared entirely ; while the third, which was so circumstanced 

 that the escape of this gas was impossible, did not disappear : 

 it seems to me, that there can be no doubt of the cause of 

 the phenomena that presented themselves: and it is certainly Charcoal less 

 a curious fact, that charcoal, which has hitherto been con- fixed th an usu- 

 6idered as one of the most fixed substances known, can unite 

 itself to oxigen, and form with it carbonic acid gas, at a tem- 

 perature much below that, at which it burns visibly. 



IV. 



Inquiries concerning the Heat developed in Combustion, with 

 a Description of a new Calorimeter ; by the Same*. 



XlLTTEMPTS have been long ago made to measure the Results of ex* 



heat, that is developed \a the combustion of inflammable periments on 



substances ; heat from 

 combustion 



* Read at the meeting of the fifth class of the French Institute, Feb. 1S?U * 

 the 24th, 1812. 



