SECTION B : CARDIFF, 1920. 



ADDEESS 



TO THE 



CHEMICAL SECTION 



BY 



C. T. HEYCOCK, M.A.. F.R.S., 



PRESIDENT OF THE SECTION. 



DuEiNG its past eighty-nine years of useful life the British Association 

 Has, in the course of its ev"olution, established certain traditions ; among 

 these is the expectation that the sectional President shall deliver an 

 adxlress containing a summary of that branch of natural knowledge with 

 which he has become especially acquainted. 



The rapid accumulation of experimental observations during the 

 last century, and the consequent necessity for classifying the observed 

 facts with the aid of hypotheses and theories of ever-increasing com- 

 plexity, make such summaries of knowledge essential, not only to the 

 student of science, but also to the person of non-specialised education 

 who desires to realise something of the tendencies and of the results 

 of modem science. 



At the present moment, when the whole world is in pause after 

 having overcome the greatest peril which has ever threatened civilisa- 

 tion; when all productive effort, social, artistic, and scientific, is under- 

 going reorganisation preparatory to an advance which will eclipse in 

 importance the progress made during the nineteenth century, such 

 attempts to visualise the present condition of knowledge as are made 

 in our Presidential Addresses are of particular value. It is, therefore, 

 hardly necessary for me to apologise for an endeavour to place before 

 you a statement upon the particular branch of science to which I have 

 myself paid special attention; whatever faults may attend the mode 

 of presentation, such a survey of a specific field of knowledge cannot 

 But be of value to some amongst us. 



I propose to deal to-day with the manner in which our present rather 

 detailed knowledge of metallic alloys has been acquired, starting from 

 the sparse information which was available thirty or forty years ago; 



