We have said that lava, or molten rock, appeared to be issuing from the very numerous cracks formed all over the flanks of the mountain. But at three points this molten rock issued in such quantities as to form great, fiery floods, which rushed down the sides of the mountain, and flowed to a considerable distance beyond its base. The largest of these lava-floods overwhelmed and destroyed the two villages of Massa di Somma and San Sebastiano, besides many country houses in the neighbourhood. [Sidenote: STEAM EMITTED FROM LAVA-CURRENT.] A very marked and interesting feature exhibited by these three lava-floods was the quantity of watery vapour which they gave off during their flow. All along their course, enormous volumes of steam were evolved from them, as will be seen by an inspection of the photograph. Indeed, such was the abundance and tension of the steam thus escaping from the surfaces of the lava-currents that it forced the congealing rock up into great bubbles and blisters, and gave rise to the formation of innumerable miniature volcanoes, varying in size from a beehive to a cottage, some of which remained in a state of independent activity for a considerable time. So far, what we have described as taking place at Vesuvius, in April 1872, has been only the repetition on a £Eur grander scale of the three kinds of action which we have shown to be constantly taking place at Stromboli; namely, the formation of cracks or fissures in the earth's surface, the escape of steam with explosive violence from these openings, often propelling rock-fragments into the atmosphere, and the outwelling, under the influence of this compressed steam, of masses of molten materials. There were some other appearances presented at the great outburst at Vesuvius, which do not seem at first sight to find any analogies in the manifestations of the more feeble action continually going on at Stromboli.