272 Researches on some important Points 



the specific heat of the gases. The numbers given by them for 

 oxygen and azotic gases do not differ from what they ought to be 

 to agree accurately with our law, except by a quantity less than 

 the probable errors of such experiments. The number for hy- 

 drogen is rather too small ; but on examining, with attention, all 

 the corrections which the authors v.ere obliged to make on the 

 immediate results of their observations, it may easily be seen that 

 the quickness with which hydrogen lowers to the temperature of 

 the surrounding bodies, compared with other elastic fluids, ought 

 necessarily to introduce into the determination relative to that 

 gas an inaccuracv from which they did not attempt to free it. 

 By taking into consideration this source of error, we are enabled 

 to explain the difference to which we have alluded, without being 

 compelled to make any false supposition. 



Having thus established the law of specific heats for elementary 

 bodies, it became very important to examine, under the same 

 point of view, the specific heats of compo\UKl bodies. Our pro- 

 cess applying indifferently to all substances, whatever their con- 

 ductibility or state of aggregation may be, we were enabled to 

 subject to experiment manv bodies whose proportions maybe con- 

 sidered as fixed ; but when we attempt to ascend from these 

 determinations to that of the specific heat of each compound 

 atom, by a method analogous to that which we employed for the 

 simple bodies, we find ourselves soon stopped by the number of 

 equally probable suppositions among which ue must make our 

 election. Since the method of fixing the weight of the atoms of 

 simple bodies has not yet been subjected to any fixed rule, that 

 of the atoms of compound bodies has been, a fortiori, deduced 

 from suppositions purely arbitrary. But instead of adding our 

 own to the conjectures before advanced on the subject, we choose 

 rather to wait till the new order of considerations which we have 

 established can be applied to a sufficiently great number of bodies, 

 and in circumstances sufficiently varied to place the opinions that 

 maybe adopted, on decisive conclusions. For the present we shall 

 only remark, that in abstracting each particular supposition, the 

 observations we have hitherto made tend to establish this remark- 

 able law, — that there always exists a very simple ratio between 

 the capacity of the compound atoms and thai of the elementary 

 atoms. 



Another consequence very important for the general theory of 

 chemical actions may likewise be deduced from our researches; 

 namely, that the quantity of heat developed at the instant of 

 the combination of bodies has vo relation to the capacity of the 

 elements : and that in the greater number of cases, this loss of 

 heat is not followed by any diminution in the capacity of the 

 compounds formed. Thus, for example, the combination of oxy- 

 gen 



