286 COMBINATION. 



have not yet reached, upon which are dependent all the 

 phenomena which we now embrace under the term 

 chemical affinity. 



Another law teaches us that when compound bodies 

 combine in more than one proportion, every additional 

 union represents a multiple of the combining proportion 

 of the first. With the difficulty which arises from the 

 sub-multiple compounds we cannot deal : further re- 

 search may render their laws less obscure. We have 

 seen that 8 parts of oxygen unite with 1 of hydrogen 

 and 14 of nitrogen. It also unites with 110 of silver, 

 96 of platinum, 40 of potassium, 36 of chlorine, and 

 200 parts of mercury, giving rise to 



Water 9 



Nitrous oxide . 22 



Oxide of silver 

 Oxide of platinum 

 Potash . 

 Oxide of chlorine 

 Oxide of mercury 



118 



104 



48 



44 



208 



In these proportions, or in multiples of them, and in 

 no others, will these bodies unite with the acids or other 

 compounds. It will, of course, be understood that any 

 other numbers may be adopted, provided they stand in 

 the same relation to each other.* 



From the discovery of these harmonious arrangements 

 was deduced the beautiful atomic theory to which allu- 

 sion has been already made. Indeed, there does not 

 appear to be any other way of explaining these phe- 

 nomena than by the hypothesis that the ultimate atoms 

 of bodies have relatively the weights which we arbi- 

 trarily assign to them, as their combining quantities. 

 These views are further confirmed by the fact, that 

 gaseous bodies unite together by volume in very simple 

 definite proportions : 100 measures of hydrogen and 



* Consult Graham's Chemistry, On Combining Proportions. 



