[371] Hakluyt, i. 122.
[372] Journal of the American Geographical Society, xii. 185.
[373] It is supposed to-day to be in Prince Albert Land, and to make a revolution in about five hundred years. Acosta contended that there were four lines of no variation, and Halley, in 1683, contended for four magnetic poles.
[374] Cf. notes on p. 661, et seq., in Bunbury’s History of Ancient Geography, vol. i., on the ancients’ calculations of latitude and measurements for longitude. Ptolemy carried the most northern parts of the known world sixty-three degrees north, and the most southern parts sixteen degrees south, of the Equator, an extent north and south of seventy-nine degrees. Marinus of Tyre, who preceded Ptolemy, stretched the known world, north and south, over eighty-seven degrees. Marinus had also made the length of the known world 225 degrees east and west, while Ptolemy reduced it to 177 degrees; but he did not, nor did Marinus, bound it definitely in the east by an ocean, but he left its limit in that direction undetermined, as he did that of Africa in the south, which resulted in making the Indian Ocean in his conception an inland sea, with the possibility of passing by land from Southern Africa to Southern Asia, along a parallel. Marinus had been the first to place the Fortunate Islands farther west than the limits of Spain in that direction, though he put them only two and a half degrees beyond, while the meridian of Ferro is nine degrees from the most westerly part of the main.
[375] Cf. Lelewel, pl. xxviii., and Santarem, Histoire de la cartographie, iii. 301, and Atlas, pl. 15.
[376] Cf. editions of 1482, 1486, 1513, 1535.
[377] The earliest instance in a published Spanish map is thought to be the woodcut which in 1534 appeared at Venice in the combination of Peter Martyr and Oviedo which Ramusio is thought to have edited. This map is represented on a later page.
[378] There was a tendency in the latter part of the sixteenth century to remove the prime meridian to St. Michael’s, in the Azores, for the reason that there was no variation in the needle there at that time, and in ignorance of the forces which to-day at St. Michael’s make it point twenty-five degrees off the true north. As late as 1634 a congress of European mathematicians confirmed it at the west edge of the Isle de Fer (Ferro), the most westerly of the Canaries.
[379] Edmund Farwell Slafter, History and Causes of the Incorrect Latitudes as recorded in the Journals of the Early Writers, Navigators, and Explorers relating to the Atlantic Coast of North America (1535-1740). Boston: Privately printed, 1882. 20 pages. Reprinted from the N. E. Hist. and Geneal. Reg. for April, 1882.
[380] Regiomontanus,—as Johannes Müller, of Königsberg, in Franconia, was called, from his town,—published at Nuremberg his Ephemerides for the interval 1475-1506; and these were what Columbus probably used. Cf. Alex. Ziegler’s Regiomontanus, ein geistiger Vorläufer des Columbus, Dresden, 1874. Stadius, a professor of mathematics, published an almanac of this kind in 1545, and the English navigators used successive editions of this one.