18 COXCEPTIOXS OF COLUMBUS 



mile used by Columbus contained 1480 meters.-^ 

 We have, then, the following: 



3,244,769 meters -=r 1480 meters = 2192.4 Italian nauti- 

 cal miles 

 -^ 39>6 (39° 10') = 56 — Italian nau- 

 tical miles to a degree 



On the basis of contemporary knowledge, there- 

 fore, the method indicated in the notes of Columbus 

 could have given no other figure than a close approxi- 

 mation to 56^ miles for the value of a degree. 



Criticism of Contemporary Charts 

 BY Columbus 



In note VII, quoted above (p. 10), Columbus 

 makes a criticism of existing charts which bears upon 

 the point at issue. "Anyone can see," he remarks, 

 ''that there is an error in the navigation charts by 

 measuring from north to south . . . (from) England 

 or Ireland ... as far as Guinea." 



Now, it is a well-known fact that the portolano 

 (navigation) charts were quite accurate for the Medi- 

 na Hermann Wagner: Die Rekonstruktion der Toscanelli-Karte vom 

 J. 1474 und die Pseudo-Facsimilia des Behaim-Globus vom J. 1492, 

 Nachrichten Kon. Gesell. der Wiss. zu GoUingen: Philolog.-Hist. Klasse, 

 1894, pp. 208-312; reference on p. 225 (quoted in Henry Vignaud: Tos- 

 canelli and Columbus, London, 1902, p. 200; A. E. Nordenskiold : 

 Periplus: An Essay on the Early History of Charts and Sailing-Directions, 

 transl. by F. A. Bather, Stockholm, 1897, p. 23). For a critical discussion 

 of the length of the nautical mile, see Hermann Wagner: Zur Geschichte 

 der Seemeile, Annal. der Hydrogr. und Marit. Meteor ol. (Hamburg), Vol. 

 41, 1913, pp. 393-413 and 441-450; on the Italian nautical mile see 

 pp. 397-400. 



