was a continued subterranean and violent rumbling noise, which lasted five hours in the night,—­supposed to arise from contact of the lava with rain-water lodged in cavities within.  The whole neighborhood was shaken violently; Portici and Naples were in the extremity of alarm; the churches were filled; the streets were thronged with processions of saints, and various ceremonies were performed to quell the fury of the mountain.

“In the night of the 20th, the occasion being critical, the prisoners in the public jail attempted to escape, and the mob set fire to the gates of the residence of the Cardinal Archbishop because he refused to bring out the relics of St. Januarius.  The 21st was a quieter day, but the whole violence of the eruption returned on the 22d, at 10 A. M., with the same thundering noise, but more violent and alarming.  Ashes fell in abundance in the streets of Naples, covering the housetops and balconies an inch deep.  Ships at sea, twenty leagues from Naples, were covered with them.

“In the midst of these horrors, the mob, growing tumultuous and impatient, obliged the Cardinal to bring out the head of St. Januarius, at the extremity of Naples, toward Vesuvius; and it is well attested here that the eruption ceased the moment the saint came in sight of the mountain.  It is true the noise ceased about that time after having lasted five hours, as it had done the preceding days.

“On the 23d the lava still ran, but on the 24th it ceased; but smoke continued.  On the 25th there rose a vast column of black smoke, giving out much forked lightning with thunder, in a sky quite clear except for the smoke of the volcano.  On the 26th smoke continued, but on the 27th the eruption came to an end.”

This eruption was also described by Sir William Hamilton, who continued to keep a close watch on the movements of the volcano for many years.  The next outbreak of especial violence took place in 1779, when what seemed to the eye a column of fire ascended two miles high, while cinder fragments fell far and wide, destroying the hopes of harvest throughout a wide district.  They fell in abundance thirty miles distant, and the dust of the explosion was carried a hundred miles away.

In 1793 the crater became active again, and in 1794 after a period of short tranquillity or comparative inaction, the mountain again became agitated, and one of the most formidable eruptions known in the history of Vesuvius began.  It was in some respects unlike many others, being somewhat peculiar as to the place of its outburst, the temperature of the lava, and the course of the current.  Breislak, an Italian geologist, observed the characteristic phenomena with the eye of science, and his account supplies many interesting facts.

BREISLAK ON THE ERUPTION OF 1794