In the sketch, fig. 1, which was made on April 20, 1874, I have shown the appearance which this interesting volcano usually presents, when viewed from a distance. The island is of rudely circular outline, and conical form, and rises to the height of 3,090 feet above the level of the Mediterranean. From a point on the side of the mountain, masses of vapour are seen to issue, and these unite to form a cloud over the mountain, the outline of this vapour-cloud varying continually according to the hygrometric state of the atmosphere, and the direction and force of the wind. At the time when this sketch was made, the vapour-cloud was spread in a great horizontal stratum overshadowing the whole island, but it was clearly seen to be made up of a number of globular masses, each of which, as we shall hereafter see, is the product of a distinct outburst of the volcanic forces. Viewed at night-time, Stromboli presents a far more striking and singular spectacle. The mountain, with its vapour canopy, is visible over an area having a radius of more than 100 miles. When watched from the deck of a vessel anywhere within this area, a glow of red light is seen to make its appearance from time to time above the summit of the mountain; this glow of light may be observed to increase gradually in intensity, and then as gradually to die away. After a short interval the same appearances are repeated, and this goes on till the increasing light of the dawn causes the phenomenon to be no longer visible. The resemblance presented by Stromboli to a 'flashing light' on a most gigantic scale is very striking, and the mountain has long been known as 'the lighthouse of the Mediterranean.' It must be pointed out, however, that in two very important particulars the appearances presented by Stromboli differ markedly from those rhythmical gleams exhibited by the 'flashing-lights' of our coasts. In the first place, the intervals between successive flashes are very unequal, varying from less than one minute to twenty minutes, or even more; and in the second place, the duration and intensity of the red glow above the mountain are subject to like variation, being sometimes a momentary scarcely visible gleam, and at others a vivid burst of light which illuminates the sky to a considerable distance round. [Illustration: Fig. 1.--Stromboli, viewed from the North-west, April 1874.] [Illustration: Fig. 2.--Map of tub Island of Stromboli. (Scale about two inches to a mile.)] [Sidenote: GENERAL FEATURES OF THE MOUNTAIN.]