Page:Great Neapolitan Earthquake of 1857 Vol 2.djvu/50

Rh 163° 30' E. of north to south. The wall was, therefore, nearly transverse to the wave.

This block had been thrown a distance horizontally of 9 feet, and its centre of gravity, when in place, had been 11 feet above the ground.

Adopting for the angle of emergence that given by the block at the Capelluccio, we have to satisfy the equation

and$$\mathrm{V^2=218 \therefore V =\ 14.765}$$ feet per second,

or a little more than a foot and a half per second above what we assumed for V at the Capelluccio. This would not alter the value taken thence, for e, however, by 1°.

It may be considered, that the actual velocity of projection was a little greater than 14.765 feet per second, as there was some little adhesion between the blocks; and, in fact, if this problem be treated in the same way as the "Camine at Polla," to which the nature of its fall and overturn was analogous, it would give a rather higher velocity, but the elasticity of the wall itself, measured the apparent velocity of the wave.

It hence would seem a legitimate conclusion, that here in the dense shaly argillaceous rocks, forming so much of the great mountain mass, between Padula and this valley, the earth wave actually did assume, a slightly increased velocity, over that which it has been ascertained to have had in the limestone; and thus we have an additional ground, upon which to account for the fearful destruction, at Saponara and Montemurro. The Casa Marotta stands at