6 - president'.s address. 



up of tliii gixaL fabric of ' natural kuowledge,' ibat Scieiiuu has not come 

 to the end of her work— has, indeed, only as yet given mankind a foretaste 

 of what she has in store for it — that her methods and her accomplished 

 results are sound and trustworthy, serving with perfect adaptability for 

 the increase of true discovery and the expansion and development of those 

 general conceptions of the processes of nature at which she aims. 



New Chemical Elements. — There can be no doubt that the past quarter 

 of a century will stand out for ever in human history as that in which 

 new chemical elements, not of an ordinary type, but possessed of truly 

 astounding properties, were made known with extraordinary rapidity and 

 sureness of demonstration. Interesting as the others are, it is the dis- 

 covery of radio-activity and of the element radium which so far exceeds 

 all others in importance that we may well account it a supreme privilege 

 that it has fallen to our lot to live in the days of this discovery. No single 

 discovery "ever made by the searchers of nature even approaches that of 

 radio-activity in respect of the novelty of the properties of matter 

 suddenly revealed by it. A new conception of the structure of matter is 

 necessitated and demonstrated by it, and yet, so far from being destructive 

 and disconcerting, the new conception fits in with, grows out of, and 

 justifies the older schemes which our previous knowledge has formulated. 



Before saying more of radio-activity, which is apt to eclipse in interest 

 every other topic of discourse, I must recall to you the discovery of the 

 live inert gaseous elements by Rayleigh and Ramsay, which belongs to 

 the period on which we are looking back. It was found that nitrogen 

 obtained from the atmosphere invariably differed in weight from nitrogen 

 obtained from one of its chemical combinations ; and thus the conclusion 

 was arrived at by Rayleigh that a distinct gas is present in the atmosphere, 

 to the extent of 1 per cent., which had hitherto passed for nitrogen. This 

 gas was separated, and to it the name argon (the lazy one) was given, on 

 account of its incapacity to combine with any other element. Subsequently 

 this argon was found by Ramsay to be itself impure, and from it he 

 obtained three other gaseous elements equally inert : namely neon, krypton, 

 and xenon. These were all distinguished from one another by the 

 spectrum, the sign-manual of an clement given by the light emitted in 

 each case by the gas when in an incandescent condition. A fifth inert 

 gaseous element was discovered by Ramsay as a constituent of certain 

 minerals which was proved l)y its spectrum to be identical with an element 

 discovered twenty-five years ago by Sir Norman Lockyer in the atmosphei-e 

 of the sun, where it exists in enormous quantities. Lockyer had given th(^ 

 name (helium) to this new solar element, and Ramsay thus found it locked 

 up in certain rare minerals in the crust of the earth. 



But by helium we are led back to radium, for it has been found only 

 two years ago by Ramsay and Soddy that helium is actually formed by a 

 gaseous emanation from radium. Astounding as the statement seems, yet 

 that is one of the many unprecedented facts which recent study has 

 brought to light. The alchemist's dream is, if not realised, at any rate 



