of the Theonj of Heat. 275 



conclude, from many Galvanic experiments made by Hissinger 

 and Berzelius, and by Davy, that all bodies which combine are, 

 "With respect to each other, at the moment of combination, pre- 

 cisely in the same electric conditions as the two poles of the pile. 

 Is it Not then probable that the cjiuse which produces the incan- 

 descence of the charcoal in the beautiful experiment just men- 

 tioned, is likewise the cause of the greater or less elevation of 

 temperature of a body during the act of combustion ? At least 

 this conclusion is founded on the strongest analogies, and ought 

 to be followed through all its consequences. Wp by no means con- 

 tend that the changes of constitution which result from chemical 

 combinations have no part in the development of heat with which 

 they are accompanied : we only mean to say that, in very ener- 

 getic combinations, this cause produces, in general, but a very 

 small part of the total effect. 



In closing this memoir, we cannot pass in silence another very 

 importai.t application, to which the exact knowledge of the spe- 

 cific weight of the atoms will lead. If, as we have reason to 

 think, we have by the foregoing considerations succeeded in deter- 

 mining this element with accuracy, we may, setting out from the 

 proper densities of bodies, calculate tlie ratios whicli exist be- 

 tween the distances of their atoms: and it is easy to see how im- 

 portant it will be, in many physical theories, to be able to esta- 

 blish a comparison between the distances of the particles, and 

 certain phaenomena which may naturally be supposed to stand 

 connected with the new element. For example, it is by examin- 

 ing the question of the dilatations under this new point of view, 

 that vve may expect to arrive at simple laws, at present quite un- 

 known. Some essavs made on the observations of different phi- 

 losophers, and on some of our own, (made with a different ob- 

 ject,) lead us to consider it very probable that there exists a sim- 

 ple relation between the dilatability of liquids and the distances 

 of their particles. The fine observations of Gay-Lussac on the 

 identity of the contractions of carburet of sulphur and alcohol, 

 setting out from their respective l)oiling points, support our opi- 

 nion ; for these two liquids present this remarkable particular, 

 that, at the temperatures at which they were compared, the di- 

 stances between their particles are nearly identical. Before, how- 

 ever, pursuing the researches on this subject, it will be necessary 

 to elucidate, as much as possible, the question of specific heats, 

 and to derluce from it all the consequences to which it Uiay lead 

 relative to tiic knowledge of the constitution of bodies. 



S 2 XLV. On 



