The stresses in all the truss members due to the unit load hung at _J_ are readily found by the single diagram shown in Fig. 31, also carefully drawn to scale. These stresses measured from the diagram are given in the table as indicated by the column _z_; they are also represented in equation (44) by the letter _z_. The quantity _s_ in equation (44) is the intensity of the stress (pounds per square inch of cross-section of member) produced by the combined dead and moving loads in each member. As shown, these stresses are least in the web members near the centre of the span, and greatest in the chord members. The lengths in inches of the truss members are shown in the proper column of the table. It will be observed that all counter web members are omitted, as they are not needed for the uniform load. The coefficient of elasticity (_E_) is taken at 28,000,000 pounds. The quantities represented by the second member of equation (44) are computed from these data, and they appear in the last column of the table, the sum of which gives the desired deflection in inches. The elements of the table show how much of the deflection is due to the chords and to the web members, and they show that disregarding the latter would lead to a considerable error. +-------+----------+---------+--------+-----+---------+ | | _S_ | _s_ | _z_ | _l_ | _w_ | +-------+----------+---------+--------+-----+---------+ | _L₁_ | +373,300 | +12,000 | +.555 | 360 | +.08563 | | _L₂_ | +373,300 | +12,000 | +.555 | 360 | +.08563 | | _L₃_ | +480,000 | +12,000 | +.833 | 360 | +.1284 | | _L₄_ | +540,000 | +12,000 | +1.125 | 360 | +.1736 | | _P₁_ | -502,300 | -9,000 | -.748 | 472 | +.1132 | | _U₁_ | -501,000 | -9,500 | -.870 | 376 | +.1108 | | _U₂_ | -544,800 | -10,000 | -1.135 | 363 | +.1472 | | _U₃_ | -576,000 | -10,000 | -1.50 | 360 | +.1928 | | _T₁_ | +84,000 | +9,000 | 0 | 324 | -- | | _T₂_ | +143,500 | +10,000 | +.3738| 472 | +.0629 | | _P₂_ | -12,000 | -1,000 | -.250 | 432 | +.00386 | | _T₃_ | +93,720 | +7,400 | +.456 | 562 | +.0677 | | _P₃_ | +12,000 | +1,000 | -.35 | 480 | -.0060 | | _T₄_ | +60,000 | +4,800 | +.625 | 600 | +.0643 | | _P₄_ | -12,000 | -1,000 | 0 | 480 | -- | +-------+----------+---------+--------+-----+---------+ Deflection for ½ truss members = 1.2300 inches. Deflection at _J_ = 2 × 1.2300 = 2.4600 inches. [Illustration: FIG. 31.] As the deflection is usually desired in inches, the lengths of members must be taken in the same unit.