C.C. NATURAL HISTORY SOCIETY, 



39 



LECTURES. 



"ARGON AND HELIUM," 



BY G. W. HEDLEY, ESQ. 



F all the numerous and important discoveries 

 made within recent years in the Science of 

 Chemistry none have evoked so much interest 

 as those of the two new gaseous elements, — 

 Argon and Helium. 



Some hundreds of years ago it was sup- 

 posed that all kinds of matter were made up 

 of only four elements, viz., earth, air, fire and 

 water. This belief was accepted by the ances- 

 tors of modern Chemists, — the Alchemists. 

 They argued that every form of matter being composed of these 

 four elements in different proportions, it ought to be possible 

 by altering these proportions to change one substance such as lead 

 into another such as gold. This belief in the possibility of trans- 

 muting the base metals into the noble metals is the keynote of 

 Alchemy, and it was not until the adherents of this creed had 

 worn themselves out in their fruitless attempts to gain their end 

 that the original hypothesis of the four elements was finally 

 abandoned. 



In the seventeenth century Robert Boyle defined the terms 

 " element" and " compound " much as they are defined now. An 

 element henceforth was any substance incapable of being split up 

 into two or more dissimilar substances. From this time substances 

 such as Gold, Copper, Sulphur, Tin, etc., were called elements, 

 since they could not be decomposed. It was natural that those 

 occurring in the free state and in large quantities should be first 

 discovered, these being all known a century ago. Since that time 

 about forty others have been found, occurring always in the 

 combined state Three important agencies have led to their 

 recognition. 



