The Florentine mile of 3,000 braccia da terra contains, according to Sig. Uzielli, 1653.6m. (as against 1481m. to the Roman mile). Hence Toscanelli estimated a degree of the meridian at 111,927m, or only 552m. more than the mean adopted by Bessel and Bayer. Since, according to the letter, one space = 250 miles, and by the map one space = 5°, we have 50 miles to a degree, which would point to an estimate for a latitude of about 42°, allowing 67 2-3 miles to an equatorial degree. Lisbon was entered in the table of Alphonso at 41° N. (true lat. 38° 41’ N.) By this reckoning Quinsai would fall 124° west of Lisbon or 10° west of San Francisco. It does not appear that the Florence MS. can be traced directly to Toscanelli, but the probability is certainly strong that we have here some of the astronomer’s working papers, and that Ximenes did not deserve the rebuke administered by Humboldt for allowing 250 miles to a space, and assuming that a space contained five degrees. Certainly Humboldt’s use of 150 miles is unjustifiable, and his calculation of 52° as the angular distance between Lisbon and Quinsai, according to Toscanelli, is very much too small, whatever standard we take for the mile. If we follow Uzielli, the result obtained by Ruge (Geschichte des Zeitalters der Entdeckungen, p. 230), 104°, is also too small.[495]
GAFFAREL’S MAP.
From a map by Gaffarel, “L’Océan Atlantique et les restes de l’Atlantide,” in the Revue de Géographie, vi. p. 400, accompanying a paper by Gaffarel in the numbers for April-July, 1880, and showing such rocks and islets as have from time to time been reported as seen, or thought to have been seen, and which Gaffarel views as vestiges of the lost continent.
[G.]Early Maps of the Atlantic Ocean.—By the Editor—The cartographical history of the Atlantic Ocean is, even down to our own day, an odd mixture of uncertain fact and positive fable. The island of Bresil or Brazil was only left off the British Admiralty charts within twenty years (see Vol. II. p. 36), and editions of the most popular atlases, like Colton’s, within twenty-five years have shown Jacquet Island, the Three Chimneys, Maida, and others lying in the mid-sea. It may possibly be a fair question if some of the reports of islands and rocks made within recent times may not have had a foundation in temporary uprisings from the bed of the sea.[496] We must in this country depend for the study of this subject on the great collections of facsimiles of early maps made by Santarem, Kunstmann, Jomard, and on the Sammlung which is now in progress at Venice, under the editing of Theobald Fischer, and published by Ongania.[497]
We may place the beginning of the Atlantic cartography[498] in the map of Marino Sanuto in 1306, who was first of the nautical map-makers of that century to lay down the Canaries;[499] but Sanuto was by no means sure of their existence, if we may judge from his omission of them in his later maps.[500]
A conventional map of the older period, which is given in Santarem’s Atlas as a “Mappemonde qui se trouve au revers d’une Médaille du Commencement du XVe Siècle.”