MODERN CHEMISTRY. 445 



connection between chemical actions, commonly so called, 

 and the operation of those great natural forces, of which we 

 have so often spoken as known to us through the material 

 actions they induce. We are thus carried, under guidance of 

 the strict laws of number, into parts of nature to which our 

 senses give us no access, and which might well seem inap- 

 proachable by human reason. 



In the preceding article, we have briefly noticed the 

 manner in which the Atomic theory has been made to 

 disclose to us these phenomena; to indicate the relative 

 weights of the molecular parts of bodies, and the whole 

 system of definite proportions of these molecules in every 

 act of chemical change and combination. The method of 

 proof is one equally simple and beautiful. It becomes more 

 stringent and complete as we extend the number of bodies 

 brought into evidence ; and find the relative proportions so 

 determined for each, strictly maintained in all their forms of 

 combination. The conclusions are as certain as any of pure 

 mathematics ; or if there be seeming defect in any part, it is 

 such only as may be due to imperfect analysis, or other 

 causes not infringing on the truth of the general principle. 



The corollaries of this great law are numerous, and all 

 deriving certainty from the same source. The most impor- 

 tant, perhaps, is the fact that compound bodies, as well as 

 simple, have their fixed combining proportions ; the law here 

 being that the combining number of a compound is exactly 

 the sum of the combining numbers, or atomic weights, of its 

 component parts. Closely akin to this is the further corol- 

 lary, that compound bodies unite together in multiples of 

 their combining proportions, as well as in single equivalents. 

 And a further circumstance, of yet higher import to chemical 

 theory, is the fact that bodies replace each other in combina- 

 tion in fixed equivalent quantities; so that in the mixture 

 of certain neutral salts, if equivalents of each be brought 



