General Results. 
39 
GENERAL RESULTS. 
14. Summary .—In the foregoing discussion we have reached 
a result which, while of great generality, is also simple in form 
and easily applicable to special cases. We have also pointed out 
the special forms assumed by the general rule when applied to 
the most important special cases. In conclusion, it will be well 
to give a summary of these general and particular results. The 
reader who has not followed the foregoing mathematical discus¬ 
sion is referred to the opening paragraphs for an explanation of 
the symbols employed. 
I. In every case in which the stress in a truss member has a 
maximum or a minimum value, the following equation is satisfied: 
n 
'2 
II. To get the greatest stress in a chord member, the truss 
should be loaded as completely as possible, and the heaviest 
loads should be brought near to G or to D;—the former if l x n 2 > 
l 2 n x , the latter if l x n 2 cl 2 n x . When the stress is a maximum 
a load will be either at C or at D. 
III. In case of a web member, if the point F falls outside the 
span, the greatest stress of one kind occurs when A C is loaded 
ns heavily as possible and D B is free from loads, the heaviest 
loads being brought as near C as possible and one load being 
.at <7; the general condition must be exactly satisfied, and takes 
the form 
in which P 2 is to be made zero, or as small as possible. For 
the other kind of stress a similar statement may be made. 
As a limiting case, if the chords are parallel, the last equa 
tion becomes 
IV. In case of a web member, if F falls between A and C , 
the greatest stress will occur when the truss is loaded as heav¬ 
ily as possible, and the heaviest loads are brought as near C as 
