Page:Great Neapolitan Earthquake of 1857.djvu/208

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160 EMERGENCE AND VELOCITY BOTH OBTAINED. If in the same locality, we are enabled to observe two different bodies, both projected, and to measure the vertical and horizontal distances to the point of fall, we can determine both the anl� of emergence of the wave-path (e) and the ma, rimum veloo of the wave. Thus, for example, let both the bodies, be projected by the second semiphas?. of the wave, and let a b and a v b' denote the coordinates in x and y, of the two trajectories; then by Eq. XL. we have -- b = a tan e -- -- b f -- a' tan e -- from which we find a  4 H cosa e a t2 4 ][ COS   �a  b' -- a  b ........ (XLIII.) Tan e - aV -- a (a' -- a) ,,,,, (,e- ,0 ....... (xLrv.) H cos  e = 4 (a b' -- a' b) V  d fithg for H i v  we find V  = g x 2 c e (a b' - a' 6) ...... (V.) In e , of t u  of a , thro off fr t  whkh ri ai, which is a ve fuent one, e tio  apply, are the me  for a y, pmjd d overtm fm e smit; e upr on tug over flint, un one arr and then ing  more or less from e e of the wall, in a try. e preding tio embm, pbably, eve  likely W cur W obseation. Digitized by Googlc