GEOGRAPHICAL LATITUDE. 765 



like class, to make way for those coustriicted on the more reliable 

 method, because based on scientific principles;' and his was destined 

 to become the fundamental work to which the maps of modern geogra- 

 ])hers might be added as a supplement.-^ If this substitution of 

 Ptolemy's method was at first disastrous in producing maps less prac- 

 ticable and perhaps also less accurate than those in vogue for mariners, 

 it was due to the fact that the mariners had in their compass mai)s exag- 

 gerated the size and importance of the bodies of water at the expense of 

 the land.^ Accordingly it was necessary to take this ap[)arent step back- 

 wards once for all, in order to establish for tUe future correct Hues for 

 the development of the science. For some time there continued to be 

 published maps of the Middle Age type, as Fra Mauro's map of the 

 world, 1459, and Bennicasa's nautical map, circa 1476;^ and even at 

 times such were issued in the same work with re-productions of 

 Ptolemy's maps, as in the work of Andre Bianco,"^ 1436. But at the 

 end of the fifteenth century the work of the great Grecian was so 

 widely circulated, at least among scientists, so generally accepted, 

 that from that time we may consider the rotundity of tlie earth -as 

 scientifically established" in Christendom, and therewith the theory of 

 latitude. That was however only the beginning. The real latitude 

 of but comparatively few places had been determined, and that gener- 

 ally inaccuratelj', while there still remained the great work of measur- 

 ing exactly a degree of latitude and thence calculating the size of the 

 earth. 



Herewith we enter upon a new era in the development of geograph- 

 ical latitude. The first essential for the required accuracy was improve- 

 ment in the instruments and methods of asti-onomical observation. 

 The gnomon is at best but a crude instrument, and the practice of 

 waiting for noon on the four days of the year when the sun's position 

 was accurately known hindered the acjcumulation of observations 

 which is necessary to exactness. ISTot only were new iustruiuents there- 

 for invented, but the astronomers turned to the ol»servatiou of the pole 

 star, by which it is easier to determine latitude, and later came the 

 tables of the daily position of sun and stars in the heavens, which 

 enables us to determine with accuracy the latitude any day or night. 



•Lelewel, Br. Ed., ii, 125. 



^D'Avezac, 300. 



^Lelewel, ii, 47, draws the contrast as follows: "La gcograpliio dos Arabcs, 

 savanto mais enibroiiiiloo, dtait dmineniuicnt contineutale ; ccUe des latins d'expcri- 

 ence, niais rcgulii-re, exclusivemont uauticjue. Celle-li\, suivant les regies dela haute 

 science, sur des bases vicieuses, fournit des produits varies et discordants, s'eniplit 

 d'inextricables erreiirs; cette autre, niarchant vers lo grand cheniin, par des seutiers 

 6troit8 mais bien battus, (Slabora runicj^ue produit pour toutes les ecoles qui se dis- 

 putaient I'exactitude de son dessin," 



^Lelewel, Br. Ed., ii, 105. 



''Ibid., 86. 



"Giinther, sStudien, 11. 



