784 GEOGRAPHICAL LATITUDE. 



giveu 75 miles to the degree.' and Aboul Hassau, 66| miles.^ The 

 measureiueut of 56§ niilei« to the degree, which seems to have been 

 most generally accepted by the Arabs,^ is nearer the truth than either 

 of the two generally accepted classical ones, as the error is probably 

 only one-tenth.* 



This, then, is the best result of Mohammedan science added to the 

 knowledge of classical antiquity. Christian Europe had as yet done 

 nothing toward solving this problem ; was even disposed to regard as 

 heretical a belief in the foundation principles thereof, until circum-navi- 

 gatioD of the globe proved beyond the possibility of a doubt the rotund- 

 ity of the earth. In the same decade in which the first voyage round 

 the world was completed, Jean Fernel, a French physician, undertook to 

 measure a degree of latitude, whose result, by a marvellous series of com- 

 pensating errors, turned out to be extremely accurate. The actuality of 

 this measurement also has been doubted f but his relation is so cir- 

 cumstantial in all its details that it seems difficult to doubt his having 

 in reality carried out tlie plan he describes, liemarking that different 

 authors give varying lengths of the degree of latitude and that even 

 among the best, one did not know which to choose, he determined him- 

 self to make the experiment, and he found by a careful calculation the 

 length of a degree to be 08 Italian miles, 95^ feet, which equal 544 

 Komau stadii, 4o|^ feet.^ Taking from Paris a carriage on which he 

 had made an attachment for counting the revolutions of one of the 

 wheels, he drove on the road toward Amiens which led directly north, 

 until by observation he found he had passed a degree of latitude. His 

 carriage wheel had made 17,024 revolutions. The diameter of the 

 wheel was 6 feet and a little more than 6 digits; hence the circumfer- 

 ence 20 feet or 4 paces ; which gave for the whole distance, 68,096 paces 

 or 68 Italian miles, 90 feet,^ which, reduced to toises and taking into 

 account the alteration made in the length of the standard toise in 1068, 

 gives 57,070 toises for the length of a degree in the latitude of Paris.^ 

 Bessel calculates that the true length is 57,055 toises.^ According to 

 Picard's calculation, Fernel measured aline of only 56' 36," which short- 

 coming was compensated by calculating the direct distance too long.'" 

 PescheP^ calls attention to the fact that he made an error of twelve min- 



iLelewel, Bres. Ed., i, Iviii-ix. 



^Delainbre, Astrou. du moyen-age, 188. 



'Ibid, 66. 



^Peschel, Gesch. der Erdkunde, 135, following Boeckh's calculation. Banernfeind 

 thinks only 6 to 7 per cent. Die Bedeutung nioderner Gradmessungen, p. 11. 



*By Snellius ; and Pescbel thinks the suspicion " nur allzu begriiudet" (Erdkunde, 

 p. 394, n. 3). 



*Lalande, quoting Fernel, Histoire de I'Acad^mie des Sciences, 1787, p. 217. 



''Ibid., p. 219. This is 5J ft. less than above given on p. 217. 



8 Ibid. 



»Kalender, etc., von Sachsen, 1876, p. 58, or 57,057 toises, Peschel, Erdkunde, 394, 

 An. 2. 



1° Picard, Mesnre de la terre, 28. 



" Erdkunde, 394, n. 3. 



