Section H. 



ENGINEERING AND ARCHITECTURE 



ADDRESS BY THE PRESIDENT, 

 Professor R. W. CHAPMAN, M.A., B.C.E., 



Adcli'/Jr Uiiii-emitii. 



THE STRUCTURE OF METALS AND THEIR BEHAVIOUR 

 UNDER STRESS. 



The pleasure that I have in accepting the honour of presiding 

 over the meetings of this section is modified by a feeling of deep 

 regret as I remember that the gentleman who was our president at 

 the last meeting of the association in Adelaide has been called away 

 by the hand of death. Mr. W. Thwaites, late Engineer-in-Chief of the 

 Melbourne and Metropolitan Board of Works, died in November, 

 1907, at the comparatively early age' of fifty-four years, after a life 

 of strenuous energj', spent in the furtheriiig of engineering progress, 

 a life that lias left its indelible record in the shape of good and 

 lasting work. After a brilliant course at the University of Mel- 

 bourne, he entered the sei-vice of the Victorian Railway Department 

 in 1871, and, with the exception of a period of three years spent 

 in the South Australian Railway Department, he remaine<l in the 

 service of the Victorian Government until 1890. He assisted in the 

 carrying out of the exploration surveys that gave Melbourne her 

 greatly increased water supply, and was afterwards responsible for 

 the designing und construction of extensive reclamation and other 

 works, including the Port Melbourne Lagoon and the Dight's Falls 

 schemes. In 1891 he was chosen Engineer-in-Chief of the Melbourne 

 and Metropolitan Board of Works, a position that he occupied till 

 his death, and the great sewerage works of Melbourne stand as a 

 lasting monument to his energy, ability, and conscientiousness. 



It is my purpose in this address to direct your attention to some 

 modern views on the stiiicture of metals and their behaviour under 

 stress, a matter which perhaps some engineers may be inclined to 

 scorn as being of purely theoretical intei-est. But I do not propose 

 even to apologise. The veiy fact that this section holds its meeting 

 under the wing of an Association for the Advancement of Scienc:' 

 shows that we, as engineers, recognise the necessary dependence ol 

 engineering progress upon the advance of pure knowledge. And 

 when the president of this section happens to be a man engaged in 

 engineering teaching and experiment at a University, it is but 

 natural that he should deal more witli the scientific aspects of the 

 subject, leaving to those actually engaged in the carrying out of 

 works the account of practical difficulties overcome. The old fight 

 between theoiy and practice lasted long; but I think Ave may regard 

 it as practically over. We all recognise that the engineer nuist have 

 some sort of tlieorv to guide him in design, and if his tlieorv is of 



