Page:Great Neapolitan Earthquake of 1857 Vol 2.djvu/30

Rh between 15° and 20°, and also horizontal movements; the latter with the largest velocity.

It is possible, therefore, that the sharp shearing off of this tower, may have arisen from some peculiarity of support that had disappeared, or other unnoticed cause. If it be concluded, that it had its origin in a wave of very acute emergence, then it would follow as most probable, that this had been delivered, upwards from the limestones, beneath the shales and other argillaceous formations of this region, as a lateral wave of dispersion, and an instant after the overthrow of the tower had been commenced by the primary wave. This might have been so, and yet from the total destruction round, no trace of the fact be discernible.

The Chiesa Madre (c). Fig. 264, (Photog. No. 266, Coll. Roy. Soc), gave from fractures—not fissures, and therefore less trustworthy—a wave-path, 134° 30' E. of north, and of emergence from 20° to apparently horizontal, and the monastery of St. Francisco (Photog. No. 267, Coll. Roy. Soc.), at d (Fig. 264) one not more than 7° or 8° from north to south, and west of north.

It seemed evident upon the whole, that the general path of the primary wave, had been very close to 38° W. of north toward the south, and with an emergence of something between 15° and 20° from the north; that the whole mass of the nob or tongue of insulated land and its rock core, upon which the city stood, had been put in motion and oscillated forward and back, both in the direction of the wave, and transverse to it, the latter being the direction of the narrow diameter of the tongue. Those latter movements were, quam prox. horizontal, and hence the complication of fissures, &c. To this may have been added, a secondary