[s. E. DAWSON] THE LINES OF DEMARCATION BU 



A^'ere exploded l)y D'Avezac, forty years ago, in his discussion with 

 Varnhagen. 



The ntter inapplicability of mathematical reasoning in questions 

 such as these is further shown at p. 190, where Mr. Harrisse sets forth 

 his mode of measuring the Cantino map and, after submitting it to 

 mathematical methods, he concludes "that no reliance is to be placed 

 ''on the metrology of that map." Again, at p. 210, the Ribeiro map 

 ia put through a similar trigonometrical course and the conclusion is 

 " that no reliance is to be placed, scientifically speaking, on the carto- 

 " graphical statements of the period." The wonder is that the attempt 

 was ever made ; but now that Mr. Harrisse has given it up we may, at 

 least, hope that lesser authorities will cease their anachronistic efforts 

 to scale off these crude and tentative maps of the old navigators as if 

 they were admiralty charts or publications of the U. S. G-eodetic 



The Siima de Gcographia of Fernandez de Enciso was published 

 at Seville in 1519 and does, indeed, give the circumference of the earth 

 as 6000 leagues. It was an estimation in round -numbers, for it was 

 equivalent to 24,000 Italian miles, and is found not only in Enciso but 

 in some other authorities. That, divided by 360, gives 16 ^[3 leagues to 

 a degree or 16-666 as Mr. Harrisse states (p. 105). The reason, there- 

 fore, of Mr. Harrisse's statement that "Enciso's equatorial degree con- 

 "tained 18-0489 of his leagues" is not apparent and a careful perusal of 

 the intricate calculations from pp. 193 to 197, in which Ferrer's leagues, 

 and Enciso's leagues, and our marine leagues, are mingled with Greek 

 stades and French metres fails to make it clear. The mixing up of 

 absolute quantities such as leagues with shifting and unknown quanti- 

 ties sucli as degrees is fatal to clear reasoning. ISTo doubt the league 

 both of Enciso and of Ferrer consists of 32 stades ; but Ferrer counted 

 21 ^Is and Enciso 16 ^\^ of them to a degree. The quantities are irre- 

 concilable and cannof be combined to form a third league. It is cer- 

 tain that neither Enciso or any one else had a league of 18-0498 to a 

 degree for there is not only his own statement as given above ; but his 

 calculation of the distance between the port of Higueras and the island 

 of San Thome, which he gives at 117 degrees and equivalent to 1950 

 leagues, and if one be divided into the other the quotient is again 16 'I., 

 leagues to a degree. The distances, at that time were inconceivably 

 erroneous but the fact of this distance being over-estimated does not 

 affect the ratio between the two quantities given. 



Returning to the Suma of Enciso it must be observed that, when it 

 was written, a more correct estimate of the length of a degree was very 

 generally accepted and to this Enciso bears most decided testimony in 



