Among the many remarkable phenomena connected with the Gulf Stream not the least remarkable is the existence of those floating meadows of sea-weed commonly known as the Gulf-weed or Sargassum, whose accumulations, within certain parallels of latitude and longitude, have given to that area the name of the Sargasso Sea. These marine prairies, as they have been called, have attracted the notice of all navigators since the time of Columbus, who, in his first voyage, received his earliest check upon falling in with them. The great pioneer entered the Sargasso Sea in lat. 26° N., and long. 48° W., and his timid shipmates at once took fright at the marvelous appearance, feeling assured that their ships would be entangled in the weed until they were starved to death, or that they were about to strike on some unknown coast. In this part, he says, “the sea was covered with such a quantity of sea-weed, like little branches of the fir-trees which bear the pistachio nuts, that we believed the ships would run aground for want of water.” They could not understand how such vast quantities of vegetation could merely float on the surface, and the appearance of a lobster among the weed confirmed their fears; and deeming it necessary that they must be either in, or approaching shoal water, they entreated the heroic discoverer to turn the ship’s head. But happily he never wavered, and on the tropic, in long. 66°, the first vessel which had ever entered the Sargasso Sea emerged again into clear water. The extent of the Sargasso Sea is in due proportion to the vast natural agency to which it primarily owes its existence. It stretches from 20° to about 65° West longitude, and from between the parallels of 20° and 45° is of considerable width, narrowing from 12° in its widest part to about 4° or 5° where least developed; while the remaining 20° of westerly extent takes the form of a narrow belt of various detached tracts, influenced as to situation by local currents, and averaging 4° or 5° only in width. An idea may be obtained of its area by the comparison of Maury, who states that it is equal to the great valley of the Mississippi; or still better, perhaps, from Humboldt’s estimate, that it was about six times as large as the Germany of his day. But, although the geographical boundaries given above are those usually recognized by hydrographers for the Sargasso Sea, it must not be supposed that they are invariable. It may, however, be correctly stated, that it occupies the great sweep made by the Azores, Canaries, and Cape de Verde Islands in the East; while the elongated westerly belt extends as far as between the Bermudas and West Indian islands.