420 LIFE OF DALTOX : 



thus governed by numerical relations in every act of union 

 or separation, it is obvious there must have been some pri- 

 mary conformation or adaptation which alone could fit them 

 to fulfill this condition. And this conclusion is alike valid, 

 whether we adopt the number of bodies which are regarded 

 as elementary under our present knowledge, or admit the 

 more probable belief that this number will be greatly reduced 

 hereafter by new methods of analysis. 



We have mentioned the neutral salts as first yielding the 

 principle of multiple combining proportions. The combina- 

 tion and separation of gases by volumes afforded the same 

 result, and by an inference still more simple and direct. 

 Two gases, chemically uniting to form a compound, invariably 

 combine in the same measured volumes of each, or in multi- 

 ples of one or the other, if there be more than one product 

 of this union. The same precise proportions are found in 

 the separation of the compounds thus formed. There is a 

 peculiar grandeur to those who look on nature aright, in the 

 simplest forms of demonstration of a great natural law. We 

 feel this when having before us the two glass tubes, receiving 

 severally the streams of oxygen and hydrogen which arise 

 from the decomposition of water one volume by measure of 

 the former to tivo of the latter and these proportions so 

 absolutely exact, that the nicest graduation of the tubes can 

 detect no deviation in the results. These results represent 

 to us not merely the contents of two small tubes, but the 

 relative volumes of the same elements contained in, and form- 

 ing by their union, the total mass of waters on the globe. 



Out of this great law of multiple proportions in all chemical 

 compounds arose the further discovery, more especially due 

 to Dalton, of the relative weight of the combining molecules 

 or atoms another vast step in the progress of natural 

 science. The method of the discovery is as striking from its 

 simplicity as the result from its grandeur. The reasoning of 



