Tebit, Almeon, Alfragano, Pedro de Aliaco[1] "in the tenth chapter of De imagine mundi and the author of the sphere in the division of the zones," Fray Juan de Pecan "in the fourth chapter of the treatise of the sphere," and the "first Admiral of the Indies,[2] as is evident from many papers made by him," each "fifty-six and two-thirds miles" or "fourteen leagues and two-thirds of a mile" to a degree, and a circumference of 5,100 leagues. "If no opposition is given to this latter ex adverso mere voluntarie," continues Colon, "then necessarily we must have recourse to verify it by experience, which is hindered by many obstacles." In further reasoning he says:]
It is clear from the above, that, supposing the measurement of the degrees to be conclusive, it is not reduced to such practical form that the place where such and such a number of leagues correspond to a degree can be told, nor is it easy to determine this; so that it will be necessary, both sides concurring, to select persons and instruments and the place for making the test. After these men had been ordered to proceed, instruction and advice must be given them, which being a huge matter and outside of the present discussion, I shall not dwell upon. If such practical experience is not acquired, then rightly and quite reasonably the measurement or size of degrees used by the authors of tables, or of almanacs and daily calculations of the stars, should be accepted; and such
