THE ships which leave Europe for the establishments in the Atlantic ocean, along an extensive coast of about three hundred and fifty leagues, cannot relay more conveniently in Africa than at the isle of Arguin, at which their commercial operations may be said to begin. The most safe anchorage is at the southern point, where vessels that draw only ten or twelve feet water may approach very near to land. Between the isle and the continent is a canal in which vessels of heavy burden, and even frigates, may anchor at the spot on which formerly stood the fort. When the Dutch took the place, they regularly fortified it, and built a fort with four bastions and deep fosses. In short, they neglected nothing that might enable them to keep perpetual possession of the isle, but this fort has disappeared; and of all their works there only remain two cisterns, which seem to have been respected both by time and men. The largest is ten fathoms wide, sixteen long, and about fifteen deep, and is about two hundred fathoms from the part containing the remains of the face of the fort. It appears to have been dug in the rock. In the midst of this spacious vault is a large well fifteen feet deep, in which all the waters unite, whether they proceed from springs or filtrate through the rock from the soil which covers it. It is asserted that the cistern contains five thousand six hundred muids of water. The smaller cistern is to the north of the first, and is an artificial vault dug like the other by the hand of man, with the assistance of explosion. The capacity of the parts which receive the water is estimated at half that of the cistern first mentioned. These two cisterns were formed by the Portuguese between 1445 and 1481, when after the fall of the Norman company they first occupied the isle of Arguin. PORTENDICK. Portendick is a bay about half way between Arguin and isle St. Louis. Its entrance is very difficult, being closed by two sand banks, which have only two or three fathoms of water; but in the middle between the two banks is a passage from 70 to 80 fathoms wide, and six deep, by the north bank; and from seven to eight on the south. On proceeding some distance you discover another pass, which cuts the northern bank at about one third of its length, and contains about five fathoms of water. The bay is only six fathoms deep; the bottom is uneven, and it is impossible to remain long here during the greater part of the year, on account of the heavy sea and breakers which are driven in by the wind. The Dutch have erected a wooden fort at Portendick, for which all the materials were prepared at Amsterdam.