But, on the other hand, he found great materials to comfort him, and to make him persist in his resolution. For Greek history, to which he then had access, had recorded two instances, which shewed that the voyage was not only possible, but that it had been actually performed, first by the Phœnicians, under Necho king of Egypt, then by Eudoxus, during the time of Ptolemy Lathyrus, who, after doubling the southern Cape of Africa, arrived in safety at Cadiz. Hanno, too, had sailed from Carthage through the Straits, and reached to 25° of north latitude in the Atlantic Ocean. In more modern times, even in the preceding century, Macham, an Englishman, returning from a voyage on the west coast of Africa, was shipwrecked on the island of Madeira, together with a woman whom he tenderly loved. After her death he became weary of solitude; and having constructed a bark, or canoe, with which he paddled over to the opposite coast, he was taken by the natives, and presented to the Caliph as a curiosity. And the Normans of Dieppe had, as a company, traded in 1364, not fourscore years from prince Henry’s time, as far as Sierra de Leona, only 7° from the Line. The prince’s humanity to his Moorish prisoners had likewise been rewarded by substantial information; they reported that some of their countrymen of the kingdom of Sus had advanced far into the desert, carrying their water and provisions along with them on camels; that, after many days travel, they came to mines of salt, and, having loaded their cargoes, they proceeded till they came within the limits of the rains; there they found large and populous towns, inhabited by a people totally black and woolly-headed, who reported that there were many countries even beyond them, occupied by numerous and warlike tribes. To complete all, Don Pedro, Henry’s brother, returning from Venice, brought along with him from that city a map, on which the whole coast of the Atlantic Ocean was distinctly traced, and the southern extremity of Africa was represented to be a cape surrounded with the sea, which joined with the Indian Ocean. No sooner was the prince thus satisfied of the possibility of a passage to India round Africa, than he set about constructing the necessary instruments for navigation. He corrected the solar tables of the Arabs, and made some alterations in the astrolabe: For, strange to tell! the quadrant was not then known in Portugal, though, a hundred years before, Ulughbeg had measured the sun’s height at Samarcand in Persia, with a quadrant of about 400 feet radius, the largest ever constructed, if, indeed, the size of this be not exaggerated.