The West Indies and the vicinity of the Mauritius seem to be two principal foci of hurricanes, from their frequency and tremendous violence in those localities. Of thirteen hurricanes, described by Colonel Reid, in his interesting attempt to develop the law of storms, eleven took place in the neighborhood of the Mauritius and Madagascar, which sanctions an opinion prevalent among seamen, that gales are commonly avoided by ships steering in a course so as to keep well to the eastward of the Mauritius. To give some idea of a tropical hurricane, the particulars gathered by Colonel Reid from various sources, respecting that which desolated several of the West India Islands in the year 1831, are here introduced. It passed over Barbadoes, St. Lucia, St. Domingo, and Cuba, swept the northern shores of the Gulf of Mexico, raged simultaneously at Pensacola, Mobile, and New Orleans, entered the adjoining states, and seems to have been disorganized by the opposition offered to its progress by the mountain region of the Alleghanies. The hurricane accomplished the distance of 2000 miles in 150 hours, at an average velocity of 13½ miles an hour, but the rate of its progressive motion was insignificant in comparison with that of its rotatory movement, a feature hereafter to be adverted to. Before its arrival at St. Vincent, a cloud was observed to the north by a resident, so threatening in its aspect and peculiar in its color, that of _olive green_, that, impressed with a sense of impending danger, he hastened home, and by nailing up his doors and windows saved his house from the general calamity. In this island, the most remarkable effect of the storm was the destruction of an extensive forest at its northern extremity, the trees of which were _killed without being blown down_. In 1832, these trees were frequently examined by Colonel Reid, and appeared not to have been killed by the wind, but by the immense quantity of electric matter rendered active during the storm. When at its height, two negroes at Barbadoes were greatly terrified by sparks of electricity passing off from one of them, as they were struggling in the darkness, in the garden of Coddrington College, to reach the main building, after the destruction of their hut. Such was the quantity of spray carried inland from the sea by the wind, that it rained salt water over the whole island, which killed the fresh-water fish in the ponds, and several ponds continued salt for some days after the storm. The afternoon that ushered in the hurricane, that of the 11th of August, was one of dismal gloom, but about four o’clock, there was an _obscure circle of imperfect light toward the zenith_ subtending an angle of 35° or 40°. Variable squalls of wind and rain, with intervening calms, prevailed till midnight, when the lightning flashed fearfully, and a gale blew fiercely from the north and north-east. At 1 A. M. the wind increased, but suddenly shifted its quarter, blowing from north-west and