414. A beam, one end of which is firmly imbedded in masonry or
otherwise secured, is occasionally called upon to support a weight
suspended from its extremity. Such a beam is shown in Fig. 55.
In the case we shall examine, A B is a pine beam of dimensions
20" × 0"·5 × 0"·5, and we find that, when W reaches 10 lbs., the beam
breaks. In experiment No. 8, Table XXIV., a similar beam required 36
lbs.; hence we see that the beam is broken in the manner of Fig. 55, by
about one-fourth of the load which would have been required if the beam
had been supported at each end and laden in the centre.
[Illustration: FIG. 55.]
We shall presently have occasion to apply some of the results obtained
by the experiments made in the lecture now terminated.
LECTURE XIII.
_THE PRINCIPLES OF FRAMEWORK._
Introduction.—Weight sustained by Tie and
Strut.—Bridge with Two Struts.—Bridge with Four
Struts.—Bridge with Two Ties.—Simple Form of
Trussed Bridge.