On Proportions in Chemical Combination' 41 



If you will grant me permission, I shall continue i 3r- 



vations, and now only remark generally, that I believe ae- 



nomena of electricity are produced by o?ie agent suscep. of 

 undergoing two distinct modificalions, the one directly of. osed 

 to the other-, each possessing different relations to matter, from 

 the other. 



I am, with much respect, sir, 



Your obliged obedient servant, 

 Witham, Essex, J. McJRRAY. 



January 16, 1815. 



XI. Letter from M. Ampkre to Count Berthollet, on the 

 Determination of the Proportions in which Bodies are com- 

 bined, according to the respective Number and Arrangement 

 of the Molecules of ivhich their integrant Molecules are 

 composed*. 



X ou have been long since informed that the important disco- 

 very of M. Gay Lussac, on the simple proportions observed be- 

 tween the volumes of a compounded gas, and those of the com- 

 ponent gases, gave rise to the idea of a theory wh.ich explains 

 not only the facts discovered by this eminent chemist, and the 

 analogous facts observed since, but which may also be applied 

 to the determination of the proportions of a great number of 

 other compounds, which in ordinary circumstances do not afiect 

 the gaseous state. 



The memoir in which I enter upon this theory in detail, i.'» 

 nearly finished ; but as occupati(jns of another description do not 

 admit of my finishing it now, I hasten to comply Vv'ith your vvish 

 of giving an abstract. 



Consequences deduced from the theory of universal attraction 

 considered as the cause of cohesion, and the facility with whicli 

 the light traverses transparent bodies, have led natural philoso- 

 phers to think that the latter molecules of bodies were held by 

 the attractive and repulsive forces which are peculiar to them, 

 at distances as it were infinitely great relative to the dimensions 

 of those molecules. 



Hence tiieir forms, with which no direct observation can 

 make us accjuainted, have no more any influence on the phaeno- 

 mena presented by the bodies which are composed of tiiem, and 

 we must seek for the explanation of these phaenoinena in tlie 

 manner in which these molecules arrange themselves with respect 

 to each other, in order to form what I call a particle. Accord- 

 ing to this notion we ought to consider a particle as the assem- 



• Annales de Cltirnie, torn. xc. p. 43. 



blage 



