The IStrengtli of Materials as Applied to Engineering. 153 



THE STRENGTH OF MATERIALS AS APPLIED TO 



ENGINEERING. 



BY JOHN NADER, 

 AsBislant United States Engineer. 



The subject herewith presented deserves, and in fact re- 

 quires, particular attention. 



It is not the intention to give tables and formulas on the 

 subject in question, but only to discuss the obscure, uncertain, 

 and therefore unreliable, manner in which information is placed 

 before the public, and, in such a manner as to call the atten- 

 tion of this and other scientific societies to this subject, in 

 order that at sometime, and I hope not a distant day, something 

 reliable may be obtained on the subject, either from existing 

 data or from those obtained from special researches. Barlow 

 and Hodgkinson appear to be the favorite authorities; but, if 

 these authors have experimented on wood of which we have 

 no knowledge, or if we have, cannot obtain or make use of, of 

 what use is repetition of the record of their experiments? 



In examining a set of tables on the strength of timber, 

 what a useless lot of materials do we meet with, for in- 

 stance, crab, elder, plum, willow and the like; and in passing 

 to the useful, how are we not mistihed by the simple word 

 deal. This in its real sense means nothing more or less than the 

 wood of the fir or pine, yet we find in most of these copied 

 tables no less than four kinds of deal, the same number of 

 firs, and also the same number of pines. The question now is, 

 how is all this to be reduced to common sense or practice ? 



So far as other timbers are concerned, the matter is not quite 

 but nearly as obscure as deal. This dealing out of spurious 

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