CHAP. I.] SUPPLEMENT TO CHAP. VH. 101 



the shear. This rule -we owe to Huniber.* "We have thus two methods of 

 calculation, -which, for the sake of convenience, we may speak of as Bitter's 

 and Humberts. Corresponding to Humber's method we have also a graphic 

 solution, based upon the same principles precisely. This we have set forth 

 in Chapter L, and may call Prof. Maxwell's method. In Chapter H, and 

 the following we have also become acquainted with the graphic solution 

 corresponding to Ritter's methocl, or the method of moments, which we 

 may speak of as Culmann's. It is to this method, based upon the proper- 

 ties of the equilibrium polygon, that the graphical statics properly owes its 

 value and fruitfulncss, and to it is due whatever pretensions it can claim 

 as a system. It will be seen hereafter that it alone can furnish a general 

 method applicable to all structures, whether framed or not ; whether all 

 the outer forces are known or not. By the same general method we are 

 enabled to find the centre of gravity and moment of inertia of areas, and 

 to solve thus a great variety of practical problems through which, how- 

 ever different, runs one universal method, one simple routine of construc- 

 tion. 



* Strains in Girders, calculated by Formulas and Diagrams. Van Nostrand, 

 New York. 



