inch.
R = modulus of rupture, pounds per square inch.
S = elastic resilience or work to elastic limit, inch-pounds per cu.

in.
J = greatest calculated longitudinal shear, pounds per square inch.
V = volume of beam, cubic inches.
W = weight of the beam.
In large beams the weight should be taken into account in calculating the fibre stress.

In (2) and (3) three-fourths of the weight of the beam is added to the load for this reason.
BENDING SMALL BEAMS _Apparatus_: An ordinary static bending machine, a steel I-beam bearing two adjustable knife-edge supports to rest on the platform, and a special deflectometer, are required.

(See Fig.
31.) [Illustration: FIG.

31 .-- Static bending test on small beam.