Page:Great Neapolitan Earthquake of 1857 Vol 2.djvu/218

Rh (Naples and Rome), a remarkable and unprecedented disturbance, occurred in the curve of registration, on the night of the 16th December, indicating a sudden jar or tremor, communicated to the whole system; nothing similar to it, was presented by the register-cards, when examined for many months previous.

The singular and unaccountable circumstance, however, is the want of sufficient time for the wave transit, between the origin south of Naples, and Rome, if we assume the disturbance here, to have been due to the first great shock, as felt at and around the origin.

No doubt rested on Padre Secchi's mind, as to the correctness of the local time of the barometer clock, and we are compelled to assume, that this perturbation of the instrument arose, from some unknown local cause not seismic, which is, under the circumstances, highly improbable, or that it was due to the first great Naples shock, an error occurring in the observation as to the time at Rome, or that it arose from the deep propagation, of a previous or premonitory shock, delivered a few seconds before the first great one, perceived at the Naples origin, and around it. I am disposed to adopt the second of these probabilities.

In observing several of the remains of edifices of ancient Rome, with my eye fresh from the constant detection, and educated by the remarking of earthquake effects, it was interesting to me, to be able to distinguish in many places, the rents and fractures that had been made, by the tremendous earthquakes that desolated the city and Campagna, between the fourth and ninth centuries of our era.

This is peculiarly striking, in some of the great rents in the Coliseum, and in the fractures of the marble shafts of