On April 23d the recording earthquake instruments, the seismographs, were greatly affected. On the evening of the 24th lava streams flowed down the cone in various directions. These streams were continued on the 25th and the 26th, so that on the night of the 26th the observatory lay between two streams of molten lava that threw out so much heat that the glass windows in the observatory were cracked, and a scorching smell was quite perceptible in the rooms. The cone of the mountain was deeply fissured, lava escaping freely from all the fissures, so that the molten rock appeared to ooze from over its entire surface, or as Palmieri expressed it, "Vesuvius sweated fire." This great cracking or fissuring of the cone was accompanied by the opening of two large craters at the summit, that discharged, with a great noise, immense clouds of steam, dust, lapilli, and volcanic bombs. These latter are very curious and consist of masses of soft lava that are thrown high into the air by the outrushing columns of steam. Being rotated or spun, as they rise in the air, they assume a spherical shape. Some of these volcanic bombs were thrown to a height estimated by Palmieri to have been nearly 4,000 feet above the top of the mountain. When the height of a projectile is known, the velocity with which it left the opening from which it was projected or thrown can be estimated, so that the volcanic bombs must have left the crater at a velocity of about 600 feet per second. On the 27th, in the evening, the lava streams ceased flowing, but the dust and lapilli continued to fall during the 28th and the 29th. On the 30th the detonations decreased and by the 1st of May the eruption was entirely over. Palmieri calculated that the quantity of molten rock thrown out during this eruption was sufficient to cover an area of about 1.8 square miles to an average depth of about thirteen feet. As we can see from the above descriptions, the volcanic activity of Vesuvius is characterized by long periods of rest followed by periods of activity. The periods of rest are measured by years, and often by centuries; the periods of activity by days or hours. But Vesuvius was not to have a long period of rest after its eruption of 1872. On the contrary, shortly after the great disaster of Martinique in 1906, it again became active, and on the 5th of April, 1906, began throwing large blocks of lava out of its central cone, and on the next day began to throw out large streams of lava, which, on April 7th, destroyed a village in the neighborhood. At the same time rumbling sounds were heard, and violent earthquake shocks shattered the windows of the houses. Professor Matteucci, the present director of the Vesuvius Observatory, made the following report on April the 8th.