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CHAPTER XVIII.
FOMURLÆ REFERRING TO CAP. D.—BODIES OR STRUCTURES PROJECTED.
Let a body, (Fig. 105), such as the coping-stone of a wall, a church bell, a ball or finial, upon a tower summit, &c.,
be thrown from its place by the earthquake wave in its first semiphase (direct shock), in the direction of wave-path , and be found projected to the ground at , in a direction contrary to the wave transit. It is required, if the angle of emergence , of the wave-path at the place, be known, to determine the velocity of projection, and vice versâ. The
