PREFACE. 



The object sought to be attained in this book was not the 

 making of an exhaustive scientific treatise on stresses, but t<> 

 ply in one a text-book suited to the usual limited time which can be 

 given to the subject, and a book of reference for the student in 

 his future practical work, and for the practical engineer whose 

 time is too much taken up to get with advantage from elaborate 

 treatises, a working theory for whatever problem he may have 

 in hand. 



This may seem a difficult object to attain in one book. The 

 method in which this object is accomplished is the only claim for 

 originality which the author makes. The points which have been 

 kept in mind are : 



1st. A nomenclature to correspond as nearly as passible 

 to general practice in this country, and arranged alphabetically 

 in a table to which reference can be made for the meaning of any 

 letter in a formula wherever found. 



2nd. An avoidance of lengthy explanations of demonstra- 

 tions with a multiplicity of letters and references to figures. The 

 figures are made to speak for themselves as much as possible. 



3rd. While elementary proofs are avoided, there will be 

 few things which the engineer, who has not studied Analytical 

 Mechanics and Strength of Materials, will have to take on faith. 

 Indeed, there is much which for the college student will be re- 

 view, but is put in on account of its fundamental importance. 



4th. Not all the matter is intended for class room work, 

 but some only for reference by the student should he have use 

 for it in his future career as an engineer. On the other hand, 

 many things should be amplified and taken up more in detail in 

 connection with the problems which the student solves. The 

 method adopted by the author is to take up a lesson first in the 

 form of a lecture combined with questions, of which the student 



makes notes. These notes are studied and reviewed at the next 



n 

 iii 



