LENGTH OF A DEGREE 27 



Estimate of the Extension of Asia Eastward 



We may now turn to examine the relation of the 

 measurement of a degree to the actual undertaking 

 of Columbus. In the quotation given above (p. 3), 

 Vignaud says: 



This fact alone [that the degree is equal to 5673 miles] 

 contains in substance the entire cosmographical system 

 which Columbus formulated later, and on which he said 

 he had based his project. If Columbus made this ob- 

 servation it is necessary to recognize that we are here in 

 the presence of a fact which may have contributed to the 

 formation of a plan having for its object the passage by 

 the west to the Indies. 



The value of 567^ miles for a degree is, indeed, the 

 key to the \vhole project of Columbus, for he does 

 not appear to have used or to have had any informa- 

 tion bearing on the extension of Asia eastward ^vhich 

 was not commonly available to his contemporaries. 

 The principal sources of his knowledge were Marco 

 Polo, Sir John Alandeville, and Ptolemy. ^^ 



The differences of opinion discernible in the fif- 

 teenth century in regard to the position of the east 

 coast of Asia resulted from different valuations of the 

 length of a degree. Thus the question of the exten- 

 sion of Asia to the east is not a separate problem but 

 is an integral part and, indeed, the conclusion of the 

 discussion in regard to the length of a degree. 



59 Ravenstein, op. cit., p. 71; Andres Bernaldez: Historia de los Reyes 

 Catolicos D. Fernando y Da. Isabel, 2 vols., Seville, 1870 (also Granada, 

 1856), reference in Vol. i, pp. 357-358; Bartolome de las Casas: Historia 

 de las Indias, 5 vols., Madrid, 1875-76, reference in Book I, Chs. 5-13 

 (Vol. I, pp. 55-102). 



