INTR OD UCTION 



or whether in addition thereto its atoms take part in 

 inducing new groupings of the existent chemical mo- 

 lecules, are questions that are as yet beyond the result 

 of human investigation. 



Had the brilliant mind of J. CLERK MAXWELL 

 (1831-1879) been spared to the world a few years 

 longer, he would probably have added as much to 

 our knowledge of the Ether as his genius had done 

 to the theories of Electro-Magnetism. (See his 

 articles "Atom, Attraction, Ether," etc., Encyclopaedia 

 Brittanica. 9th edit.) 



When men began seriously to investigate phe- 

 nomena under the light of inductive reasoning, almost 

 the first step was to discard the old views of the com- 

 position of Matter and the vague four elements of the 

 Alchemists : Air, Water, Earth and Fire, that lent to 

 substance its properties. Then was substituted there- 

 fore the definition of an element in its chemical 

 meaning : "A substance that cannot be separated into 

 its constituents/' This definition conferred individual 

 characteristics upon the atoms postulated by Democ- 

 ritus that by him were considered without properties 

 other than having motion; the four elements: Air, 

 Water, Fire, etc., furnishing the " accidents " that 

 distinguished the kinds of matter. From the true 

 conception of the elements soon arose that of their 

 molecular groupings and the laws of chemical affinity ; 



(xviii) 



