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136 reaching it on the 15th, having been now more than a month at sea. Having made two sections right across the Atlantic, all looked to enjoying a few days on land, but it was not to be so, for most unluckily a rather severe epidemic of small-pox had broken out at Madeira also shortly before, and Captain Nares did not think it prudent to give leave; accordingly on the 18th of July they commenced to make a section along the west coast of Africa. It was the rainy season; each day would bring them nearer to the equator, and it was scarcely possible to look forward to other than disagreeable times. On the 19th they were off Palma Island, one of the Canaries; then they bore down on S. Antonio, one of the Cape Verd islands, and were at St. Vincent on the 27th of July.

The botany of this island, so noted in the old gazetteers for its wood, water, wild goats, turtles, and saltpetre, was carefully explored. As seen from the sea, the rocks presented a singular appearance, owing to the presence of a thick incrustation at water-mark of masses of calcareous algæ, which either follow the forms of the rocks or occur in rounded masses, their delicate tints of white, light pink, or cream color, considerably heightening the effect. These incrustations are frequently bored by Lithodomus candigerus and other molluscs, and small sponges and polyzoa occupy the cavities between them and the rocks.

Leaving the Cape Verd Islands, on the 13th of August they were off the Bissagos Islands, and found bottom at a depth of twenty-five hundred and seventy-five fathoms. Continuing to cruise along the coast, on the 14th they were west of the Loss Islands; on the 15th they passed Sierra Leone; on the 19th they were off Cape Mesurado, still in depths of twenty-five hundred fathoms; and on the 21st they had run as far along the western coast of Africa as they intended, being then off Cape Palmas, and the "Challenger's " course was shaped for St. Paul's Rocks. These rocks lie about 1° north of the equator, and in longitude 29° 15m. W., being about midway between the South-American and African coasts. Although rising to a height of some fifty to sixty feet above the sea-level, yet they are mere rocks, not more than a quarter of a mile long. The sea deepens quickly in the vicinity of the rocks to depths of from fifteen hundred to twenty-two hundred fathoms. The wash of the waves is such that even seaweeds cannot retain their positions on the rocks.

Proceeding still in a south-west direction, the little group of islands called Fernando Noronha was reached on the 1st of September, and some days were spent exploring it. The group consists of a principal island about four miles long by three and a half broad, and several smaller ones; it is situated in the Atlantic, in about lat. 3° 58m. S., long. 32° 22m. W., and about two hundred miles from the nearest point of the American coast. The islands appear to be of volcanic origin; the peak on the northern side of the principal island rises to a height of one thousand feet; it is a mass of bare rock, the summit of which is quite inaccessible. The cliffs are chiefly composed of columnar basalt. The sea-depth in the neighborhood is from one thousand to two thousand fathoms. Trees abound on the higher parts of the island, and wondrous creepers cluster together in the branches of the trees. A species of Cereus was found by Mr. Mosely on the cliffs. Only one grass (Oplismenus colonus) was found on the main island, but although shady, moist places occur about St. Michael's Mount, neither on this nor on the main island were any ferns, mosses, or hepaticæ found, and lichens were very scarce. Among the principal cultivated fruits are bananas and melons, the latter being very plentiful, and of a peculiarly fine flavor. Sugar-cane, cassava, maize, sweet potatoes, were grown in large quantities. The species of land animals on the island are not numerous, but individuals of several of them are most abundant; two species of lizards are recorded from the islands, one being peculiar to the group.

On the 4th of September the "Challenger" was some ninety miles south of Cape St. Roque, in twenty-two hundred and seventy-five fathoms, with Globigerina ooze. On the 8th she was off Parahyba, in two thousand and fifty fathoms, with mud. On the 9th the sounding gave a depth of only five hundred fathoms off Cape San Agostinho. The depth increased off Macayo (September 11) to 1,715 fathoms, diminishing off the mouth of the river San Francisco to twelve hundred fathoms, and as the coast at this spot was approached to seven hundred fathoms. On the 14th the "Challenger" was at Bahia, and stopping there a short time she proceeded for a section across the Atlantic from Bahia to the Cape of Good Hope. Owing to unfavorable winds and other causes, the little island of Trinidad, an island whose vegetation was then totally unknown, had to be