Page:Great Neapolitan Earthquake of 1857 Vol 2.djvu/414

Rh vertical increases, and also of reduction of wave velocity. Thus—

There is an obvious increase of amplitude, as some function of the distance directly, but in what precise ratio, it would be useless to inquire, from such mere approximations to accurate measures of the latter.

Again, in the following table, there is apparent an equally distinct tendency to diminished velocity as the distance from the origin increases—

Moliterno diverges a little from the law of continual decrease, and Tramutola and Saponara, had they been inserted, would have done so still more, but these both had special causes of increased velocity, as already recorded.

We shall find the same phenomenon presented, if we take another line of wave-path, for example, that nearly north from the seismic vertical, and east of it—