Section B \^ , ^*'^ /:: 



CHEMISTRY, METALLURGYX^Vj^ 

 ana MINERALOGY 





ADDRESS BY THE PRESIDENT: 



Professor BERTRAM D. STEELE, D.Sc. 



Professor of Chemistry in the University of Queensland, Brisbane. 



The subject that I have chosen for the annual address this year has 

 been selected in the belief that a useful purpose would be served 

 by calling attention to the manner in which our conventional views 

 are influenced by the fact that the majority of the chemical reac- 

 tions which we study take place in aqueous solution. 



There is an opinion, never perhaps formulated, but very often 

 unconsciously held, that " wet-way analysis " is perhaps the most 

 important branch of chemistry. Perhaps in the minds of some 

 students the idea may have become developed that it is chemistry — 

 an idea which might certainly be expected occasionally from the 

 fact that it is frequently the only branch of chemistry that is 

 taught in some of our institutions. 



A few examples will illustrate the results of our concentration 

 of effort and instruction on wet-way reactions. 



Thus barium sulphate is regarded as one of the most insoluble 

 of substances, and its chemistry is usually dismissed with the 

 statement of this fact. But whilst this is true of water as solvent, 

 it dissolves freely in concentrated sulphuric acid. Again, we 

 classify substances as crystalloids and colloids solely on the in- 

 formation derived from the study of aqueous solutions ; but as a 

 matter of fact sodium chloride, a typical crystalloid, may and does 

 behave as a colloid when in solution in benzol. It is true that 

 chemists are beginning to recognise that we must rather speak of 

 a crystalloid or colloid state of matter than of crystalloid and colloid 

 substances. As another example, we may consider the fact that 

 in a standard English treatise ammonia is spoken of as a strongly 

 basic substance, having a pungent alkaline taste, etc, a statement 

 which is certainly true of an aqueous solution of ammonia, but not 

 of the pure substance, the behaviour of which in the absence of 

 water is entirely different, though no less interesting and important. 



