CHEMISTRY 



WILLIAM GEORGE BROWN 



Professor of Chemistry 



In this course of non-technical lectures on the natural 

 sciences, following an arbitrary and more or less conventional 

 classification, it has fallen to my lot to present that branch 

 of natural science without which, or without the objects of 

 its investigations, no other natural science could exist. I say 

 no other natural science, not no other science. It is the basal, 

 the fundamental natural science, its ultimate as well as its pri- 

 mary aim being the nature of matter. 



Whilst it has always dealt with matter or some manifes- 

 tation of matter, the "purpose of chemistry seems to have 

 changed much from time to time. At one time chemistry 

 might have been called a theory of life, and at another time 

 a department of metallurgy ; at one time a study of combus- 

 tion, and at another an aid to medicine ; at one time an attempt 

 to define a single word, the word element, and at another time 

 the quest of the unchanging basis of all phenomena," assum- 

 ing that there is a basis. Chemistry has appeared to be some- 

 times a handicraft, sometimes a philosophy, sometimes a mys- 



Note. The writer is indebted for much of the following to 

 the addresses of Professor Sir J. J. Thomson to the British Asso- 

 ciation for the Advancement of Science and of Professor B. Ruther- 

 ford to the Mathematical and Physical Section of the same associa- 

 tion at its meeting in Winnipeg, Manitoba, 1909; and among other 

 works and papers to Sir J. J. Thomson's "Electricity and Matter"; 

 to M. M. Pattison Muir's "History of Chemical Theories and Laws"; 

 to E. E. Fournier d' Albe's "Electron Theory"; to Sir W. Crooke's 

 "On Radiant Matter", American Journal of Science and Arts, Vol. 

 XVIII, p. 241, 1879; to E. Rutherford and H. Geiger's "An Electri- 

 cal Method of Counting the Number of a particles from Radio- 

 a^tive Substances", Proceedings of the Royal Society of London, 

 Vol. LXXXI, p. 141, 1908, 



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