On the colored and beautifully engraved map of the world of Gulielmus Blaeuw (Amsterdam, 1642) are two side maps, one of the Arctic, the other of the Antarctic, Circle. The latter represents not only the entire Antarctic Circle as unbroken land, but also extends this great supposititious continent some distance to the northward of the sixtieth parallel and gives to it the name Magallanica Terra Australis Incognita. This mythical Magellanic continent held its place, a subject of mystery and interest to every geographer, until Captain James Cook, the greatest of navigators, either ancient or modern, attempted its definition or solution. His success here as elsewhere was marvellous, and on January 17, 1773, in the Resolution, first of all men, Cook penetrated the ice-bound wastes of the Antarctic regions, reaching 67° 15´ S., on the fortieth meridian E. In the following summer he completed his circumnavigation of Southern seas in high latitudes, and penetrating the Antarctic Circle at three widely separated points, attained, in January, 1774, in 117° W., the extraordinary high southern latitude of 71° 10´. Cook thus "put an end to the search for a southern continent, which had engrossed the attention of maritime nations for two centuries." [Illustration: Charles Wilkes. (From a portrait by T. Sully.)] Cook's discoveries led to erroneous conclusions as to the physical constituents of the Antarctic regions. Although he had reached the Great Southern Circle at four different places, and nearly attained it at the fifth, yet no land therein, either island or continent, met his eager gaze; instead there everywhere met his view a close pack of ice-floes of enormous height and extent, with a few wind-caused breaks or channels. Hence many geographers concluded that the Antarctic regions were ice-covered seas, either totally or in greater part. To-day, in the light of modern science and discovery, the opinion prevails that there is an extensive ice-clad Antarctic land, possibly rising to the dignity of a continent; and toward this conclusion no explorations have more directly and largely contributed than those of the American sailor and explorer, Charles Wilkes, of the United States Navy. The first Antarctic land ever discovered was by an American sealer, Captain Palmer, from Connecticut. Bellingshausen, of the Russian Imperial Navy, in his voyage of 1821, that resulted in the discovery of the islands of Peter and Alexander, on the sixty-ninth parallel, fell in with the Yankee skipper immediately after he had discovered the land, to which Bellingshausen justly attached Palmer's name. Palmer's Land, extended into the Antarctic Circle by Biscoe's discoveries of 1832, merges into Graham Land of the latter explorer.