84 EXPERIMENTS OF DULONG AND HESS 



Marcet, who found that equal volumes of all gases 

 are equally heated and cooled by equal additions 

 and subtractions of caloric. 



The following experiments of Dulong and 

 Hess, performed with a view of ascertaining the 

 relative quantities of caloric evolved during the 

 combustion of several gaseous bodies and a few 

 metals, will be found more instructive. 



Grammes of 



Atomic com- water raised 

 Substances employed position 1 centigrade. 



Litre of Hydrogen 3,102 



Light carburetted Hydrogen . H 2 C 1 9,587 



Olefiant gas H 2 C 2 15,338 



Carbonic oxide OlCl 3,130 



Cyanogen C 2 N 1 12,269 



Alcohol vapour C2H3O1 .. 14,375 



jEther vapour C 4 H 5 O 1 . . 32,254 



" Turpentine vapour .... C 10 H 8 70,607 



Carbon vapour equal to 1 litre in the gaseous state .... 7,858 



1 Litre of Oxygen gas with iron 6,2 16 



1 Tin 6,508 



1 Antimony 5,552 



1 Zinc 7,577 



1 Cobalt 5,721 



1 Nickel 5,333 



Mean of the six metals 6,151 



To these may be added the results of M. Des- 

 pretz, who found, that during the combustion of 

 1 Ib. of different substances, caloric enough was 

 evolved to raise the following quantities of water 

 from 32 to 212. 



Substances employed. Quantities of water. 



1 Ib. of Hydrogen 236-4 Ibs. 



Charcoal from wood . . 75 



