Scr. XIV. CHEMICAL AFFINITY. 103 



times heavier than an atom of hydrogen. In the same 

 manner sulphuretted hydrogen gas consists of sixteen 

 parts by weight of sulphur and one of hydrogen ; there- 

 fore, an atom of sulphur is sixteen times heavier than 

 an atom of hydrogen. Also carbonic oxide is consti- 

 tuted of six parts by weight of carbon, and eight of 

 oxygen ; and as an atom of oxygen has eight times the 

 weight of an atom of hydrogen, it follows that an atom 

 of carbon is six times heavier than one of hydrogen. 

 Since the same definite proportion holds in the compo- 

 sition of all substances that have been examined, it may 

 be concluded that there are great differences in the 

 weights of the ultimate particles of matter. M. Gay 

 Lussac discovered that gases unite together by their 

 bulk or volumes, in such simple and definite proportions 

 as one to one, one to two, one to three, &c. For 

 example, one volume or measure of oxygen unites wkh 

 two volumes or measures of hydrogen in the formation 

 of water. 



Affinity modified by the electrical condition of the 

 particles of matter, has hitherto been believed to be the 

 cause of chemical combinations. However, Dr. Fara- 

 day has proved by experiments, on bodies both in solu- 

 tion and fusion, that chemical affinity is merely a result 

 of the electrical state of the particles of matter. Now 

 it must be observed that the composition of bodies as 

 well as their decomposition, may be accomplished by 

 means of electricity ; and Dr. Faraday has found that 

 this chemical composition and decomposition, by a. given 

 current of electricity, is always accomplished according 

 to the laws of definite proportions ; and that the quan- 

 tity of electricity requisite for the decomposition of a 

 substance is exactly the quantity necessary for its com- 

 position. Thus the quantity of electricity which can. 

 decompose a grain weight of water is exactly equal to 

 the quantity of electricity which unites the elements of 

 that grain of water together, and is equivalent to the 

 quantity of atmospheric electricity which is active in a 

 very powerful thunder-storm. These laws are univer- 

 sal, and are of that high and general order that charac- 

 terize all great discoveries, and perfectly agree with 

 Professor Mossotti's theory. 



