A single glance at this chart displays the principal well-known currents of the Atlantic ocean. The general tendency of the bottles to go to the eastward in the northern parts of this sea, and to the westward in lower latitudes, is at once apparent. It is equally evident that to the southward of the parallel of 40° N. on the eastern side of the Atlantic the bottles drift to the southward, while those again in the vicinity of the Canaries and Cape Verd Islands take a westerly direction. Those further south, lose themselves among the West-India Islands, and some penetrating further are found on the coast of Mexico, between Galveston and Tanessied. A few manifest the effects of the counter-current of the celebrated Gulf-stream, while others again, on the western side of the Atlantic, from about 40° N., are set to the eastward. Indeed, there seems to be a determination of all to the northward of the parallel of 40°, or that of Philadelphia on the American seaboard, to make their way to the eastward--some to the coast of France, in the Bay of Biscay, others to the western shores of Great Britain and Ireland, and others again to the shores of Norway. We thus recognize distinctly, first the Portugal current, setting southward; then the equatorial current, influenced by the trade winds; then the extraordinary effects of the waters of the Gulf-stream flowing northward along the American coast, over the banks of Newfoundland--one portion following its north-east course and penetrating to Norway, and another continuing easterly into the Bay of Biscay. But let us particularize a few of the remarkable journeys made by these glass voyagers over the deep. The _Prima Donna_ was thrown over off Cape Coast Castle, on the west coast of Africa, and after a voyage of somewhere within two years was found on the coast of Cornwall. Now, to have arrived there, it must have been carried eastward by the well-known Guinea current, and reaching the Bights of Biafra and Benin it would meet the African current then coming from the southward, with which it would recross the equator and travel with the equatorial current through the West-India Islands, and getting into the Gulf-stream, would be carried by this to the north-east, and thus would be landed on the Cornish coast, after making a detour of many thousand miles. But curious as this is, it is not the only instance, for we find that the _Lady Montagu_, setting out in nearly 8° S. lat., about midway between Brazil and Africa, a position which would fairly place it in the equatorial current, made the same voyage, but landed at Guernsey, having accomplished the course in 295 days, or between the 15th October, 1820, and the 6th of August, 1821. Confining ourselves now to the area included between 30° N. lat. and the equator, the general effect of the heat of the Gulf of Mexico in forcing the waters thither is plainly indicated by the direction which the bottles have followed that are included within those limits.