Page:Great Neapolitan Earthquake of 1857.djvu/509

Rh they fell and leaned, having gone over too far to recover their position at the return stroke. Those at the opposite, or south side, were at the same moment thrown out of plumb forwards, or towards the front of the altar, and finding no wall to support them, fell altogether.

In the Caffé of Gaetano Mallione, a number of bottles of the form of foreign wine bottles, full to the corks of Rosolio, stood upon a shelf, at 8 feet high from the floor, running along the west side of a wall, whose length was N. 155° east. The owner, an intelligent fellow, replaced the bottles for me in the position in which he stated he had found them in the morning after the shock. (Sketch No. 243, Coll. Roy. Soc.) Those towards the back of the shelf, (which was about 15 inches wide), leaned back against the wall, and against each other, sloping towards the east and south. Several that had stood upright close to the edge of the shelf, (which had a little ledge or curb of about three-quarters of an inch high, rising at its front edge), had been pitched over and thrown upon the floor and broken. The spots upon which these had landed, I found were on the average, three feet horizontally from where the bottles had stood on the shelf. The direction of throw was about 125° E. of north towards the N. W.; omitting one, thrown in the apparent direction $$x$$ to $$y$$.

If we assume the emergence to have been 15° here, we have

$$e = 15^\circ. a = 3. b = 8.$$

and the normal velocity of the wave here given by the equation

$$\mathrm{V} = \sec e \sqrt{ \frac{a^2}{b - a \tan e} \times \frac{g}{2} }$$