All the discoveries made by others, in the lifetime of Columbus, on the coasts of the western continent (except that of Cabral) were directly due to the first voyage of the Admiral, to his marvelous prevision in boldly sailing westward across the sea of darkness, and are to be classed as Columbian discoveries. This was clearly laid down by Las Casas, in a noble passage. "The Admiral was the first to open the gates of that ocean which had been closed for so many thousands of years before," exclaimed the good bishop. "He it was who gave the light by which all others might see how to discover. It can not be denied to the Admiral, except with great injustice, that _as_ he was the first discoverer of those Indies, _so_ he was really of all the mainland; and to him the credit is due. For it was he that put the thread into the hands of the rest by which they found the clew to more distant parts. It was not necessary for this that he should personally visit every part, any more than it is necessary to do so in taking possession of an estate; as the jurists hold." This generous protest by Las Casas should receive the assent of all geographers. The pupils and followers of Columbus, such as Pinzon, Ojeda, Nino, and La Cosa, discovered all the continent from 8 deg. S. of the equator to Darien, thus supplementing their great master's work; while he himself led the way, and showed the light both to the islands and to the continent. Although none of the charts of Columbus have come down to us, there still exists a map of all discoveries up to the year 1500, drawn by the pilot Juan de la Cosa, who accompanied him in his first and second voyages, and sailed with Ojeda on a separate expedition in 1499, when the coast of the continent was explored from the Gulf of Paria to Cabo de la Vela. Juan de la Cosa drew this famous map of the world (which is preserved at Madrid) at Santa Maria, in the Bay of Cadiz, when he returned from his expedition with Ojeda in 1500. It is drawn in color, on oxhide, and measures 5 feet 9 inches by 3 feet 2 inches. La Cosa shows the islands discovered by Columbus, but it is difficult to understand what he could have been thinking about in placing them north of the tropic of cancer. The continent is delineated from 8 deg. S. of the equator to Cabo de la Vela, which was the extreme point to which discovery had reached in 1500; and over the undiscovered part to the west, which the Admiral himself was destined to bring to the knowledge of the world a few years afterward, Juan de la Cosa painted a vignette of St. Christopher bearing the infant Christ across the ocean. But the most important part of the map is that on which the discoveries of John Cabot are shown, for this is the only map which shows them. It is true that a map, or a copy of a map, of 1542, by Sebastian Cabot, was discovered of late years, and is now at Paris, and that it indicates the "Prima Vista," the first land seen by Cabot on his voyage of 1497; but