Combination of Bodies with Oxygen, 327 



in ever}' 100 vols., in accordance wilh the observation first 

 made by Dr. J. Davy. It is necessary, in reducing the results, 

 to take into account the heat produced by the combustion of 

 this portion of carl^onic oxide. In order to ensure the com- 

 plete combustion of the gas, and at the same time to diminish 

 the force of the explosion, nearly four and a half volumes of 

 oxygen were taken for every volume of olefiant gas. 



M 364.'8 c.c. S64--0 c.c. 364.-2 c.c. 



Mc 363-9 c.c, 363-1 c.c. 363-9 c.c. 



R 110-3 c.c. 106-4. c.c. 110-4! c.c. 



Re 111-2 c.c. 107-3 c.c. 111-3 c.c. 



B 30-15 in. 30-23 in. 30-23 in. 



T 13°-6 13--3 13°-7 



E 0°-8 l°-0 l°-0 



I 3^-015 .3°-163 3°-033 



Ic 3°-017 3-166 3°-036 



W 265-3 grms. 255-7 grms. 264-2 grms. 



V 28-1 grms. 28-1 grms. 28-1 grms. 



1. 2. 3. 



15056 14.979 15012 



Hence we obtain for the heat evolved during the combina- 

 tion of — 



One litre olefiant gas with oxygen . 15016 

 One litre oxygen with olefiant gas . . 5005 

 One gramme oxygen with olefiant gas 3483 

 One gramme olefiant gas with oxygen 11942 

 The experiments of Dulong vary from 15051 to 15576 for 

 one litre of olefiant gas. 



Corrected for the heat produced by the condensation of the 

 vapour of water, the number 3483 given above becomes re- 

 duced to 3252, and the other numbers in the same proportion. 



§ II. Combination of Oxygen with Solid a7id Fluid Bodies. 



A considerable modification of the apparatus was required 

 for the determination of the heat produced during the combi- 

 nation ofsoMd and liquid substances with oxygen. The slow- 

 ness of the coml)ustioii in most cases made it necessary to 

 operate upon a larger scale ; and as the ajiparatus could no 

 longer be inverted, it was also necessary to distribute the heat 

 by a diflerent method. 



Fig. 1 exhibits the general form of the apparatus. The 

 coml)inati()n took })lace in a copper vessel of about four litres 

 capacity. The combustible was phiced in a platina cup, shown 

 in fig. 2, which is suspended from the lid of the copper vessel 

 by means of platina wires. A iburlh wire, also of platina, but 



