28 CONCEPTIONS OF COLUMBUS 



A resume of the history of the measurement of a 

 degree is not necessary here. Suffice it to say that, 

 among the Arabs, ^° Ptolemy's degree was reckoned 

 at 66 f/^ miles, or 22 2/9 parasangs. We have seen 

 (p. 13) that as a result of the measurement under the 

 Caliph Al-AIamun it was estimated at 18 8/9 para- 

 sangs, or 56^ miles. From these figures there re- 

 sulted varying estimates of the size of the earth. 

 Thus, the Catalan atlas of 1375 gives the circumfer- 

 ence as 20,052 miles ;^^ the Fra Alauro map, 1459, 

 gives it as 22,500 to 24,000 miles i^^ Columbus rated 

 it at 20,400, according to the marginalia (notes IV, 

 VII, VIII) quoted above. Of these estimates, that 

 of 66^-^ miles to a degree, or 24,000 miles circumfer- 

 ence, is the highest, and it would seem to be in 

 comparison and in contrast with this figure that 

 Columbus makes his reiterated statement. 



According to a legend on the Bartholomew Colum- 

 bus map of ca. 1503*''^ (Fig. 7), Columbus and Mari- 

 nus of Tyre reckoned the distance from Cape St. 

 Vincent to Cattigara at 15 hours, or 225 degrees. 

 Ptolemy made the same distance 12 hours, or 180 

 degrees. Vignaud criticizes Columbus for going 



60 Geographic d'Aboulfeda, Vol. i (Introduction), pp. cclxviii ff. ; Vol. 

 2, Part I, pp. 17-18; Lelewel, op. cit.. Vol. i, pp. xxii-xxiv; Vivien de 

 Saint-Martin, op. cit., pp. 250-253. 



61 Buchon and Tastu, op. cit., p. 7. 



62 Placido Zurla: II mappamondo di Fra Mauro, Venice, 1806, p. 21. 



63 F. R. von Wieser: Die Karte des Bartolomeo Colombo iiber die 

 vierte Reise des Admirals, text and facsimile of three maps, reprint from 

 Mitt, des Inst, fiir Osterreichische Geschichtsforschung, Innsbruck, 1893 

 (maps reproduced in Nordenskiold, Periplus, pp. 167-169). 



