On the recent Eruption of Vesuvius in December 1861
Authors: Tchihatcheff M. Pierre de 
Published: October 2009

On the 8th of December the ground in the neighbourhood of Torre del Greco was shaken by repeated earthquakes from dawn up to 3 o'clock in the afternoon. As many as twenty-one distinct shocks were counted there, but only one of them was felt at Naples. At the hour above mentioned the atmosphere over Torre was wrapt in complete darkness, clouds of ashes having been projected from several mouths which had opened on the slope of Vesuvius, a short distance above the town. Early on the next day (the 9th) I visited Torre del Greco, and leaving the town below, mounted towards the stream of lava which had in the preceding night poured forth from the apertures already mentioned. It had cooled so rapidly that I was enabled to walk upon the scoriaceous crust, though the interior was so hot that my stick took fire on being thrust into its cracks.

After proceeding about 600 mètres to the N.E., I came to the smoking hills, which were still vomiting glowing scorim and ashes so abundantly as to prevent a near approach. The white steam and black ashes, ejected from them with violent shocks resembling the intermittent puffs of a steam-engine, rose in globular masses so as to form a columnar shaft, which, spreading laterally at a great height, reproduced the “pine” of Pliny. On my return to Torre del Greco I saw two new mouths open before me. About this time the central cone of Vesuvius, which had been tranquil hitherto, began to eject steam and ashes in thick clouds, attended by frequent flashes of lightning. The explosions of the new craters, as well as the flow of the lava, ceased almost wholly about the third day, viz. by the 12th of December.

On the 16th heavy rains fell, the weather having been quite clear and tranquil up to that time. On a second visit made on the 23rd of December, I ascertained the number of opelfings, marked by minor cones with funnel-shaped craters, that had been formed on the flank of the mountain were about twelve--ranged close together on a line from E.N.E, to W.S.W. at the distance of about 600 metres S.S.E. from the old lateral crater whence the lava-stream of 1794 proceeded which had poured down on Torre del Greeo. Thus it appears that a fissure had on this occasion been formed in the side of the mountain, either on the prolongation of that of 1794, or parallel and close to it. The lavas produced by the two eruptions are also almost identical in mineral character, being very poor in leucite, but rich in augite crystals.

On returning to Torre del Greco, I was surprised to find the principal fountains of the town overflowing with an excessive supply of water, as in general during eruptions the springs are rather apt to fail. Bubbles of carbonic acid gas were rising abundantly from the water. Many of the cracks which had been formed by the earthquakes in the pavement of the streets of the town were seen, it is said, to emit small flames (of carburetted hydrogen ?). It is certain that the shore beneath Torre del Greco was permanently elevated by above a metre'a long white line composed of mollusks and zoophytes attached to the rock, which only live under water, being now generally raised that much above the sea-level, through a space of at least two kilometres.

The cone of Vesuvius continued to smoke at intervals for several days. On the 23rd of December ashes fell abundantly in the streets of Naples—a circumstance that has not occurred since 1822.