044 ROYAL SOCIETY OF CANADA 



That the true circumference of the earth at the equator is 180,000 stades, 

 at the rate of five hundred stades to a degree according to his calculation, 

 and counting eight stades per mile, are 22,500 miles, whicn are 5,625 leagues 

 at the rate of four miles per league in Castillian reckoning, each degree com- 

 ing to fifteen leagues and (wo hundred and twenty-five parts of three hundred 

 and sixty. And in the same Book, chapter five, he says that the circle of the 

 tropics is 164,072 stades, which are 20,584 miles, and 5,146 leagues, making for 

 each degree fourteen leagues and one hundred and six parts of three hundred 

 and sixty. Moreover, according to Strabo, Alfragano, Ambrosi, Macrobi, 

 Teodosi and Euristhcnes, the said.circumference of the earth is 252,000 stades, 

 the which 252,000 stades, at the rate of eight stades per mile, are 31,500 

 miles, and at four miles per league, are 7,875 leages. Item : — By the circle of 

 the tropics the circumference is 7,204 leagues and seventy-two thousand parts 

 of one hundred and eighty thousand; and I decided it by the rule of three, 

 saying if 22,500 miles at the equator according to Ptolemy give me 7,875 for 

 the said equator, what will 20,584 miles of the circle of the tropics give me ? 

 And in this way you v.-ill arrive at the above 7,204 and a half leagues almost, 

 according to the said learned men. 



The said circle of the tropics is shorter than the equinoctial circle by 

 670% leagues, which is, at four miles per league. 2,682 miles, according to the 

 above calculation summed up and proved throughout. That is, however, cal- 

 culating according as the above-mentioned learned men direct, 700 stades to 

 a degree; although Ptolemy allows no more than 500 stades to a degree, as 

 above said in the already mentioned book, r/c situ orliis. 



11. Item : — It is to be noted that on the equinoctial circle each degree has 

 twenty-one leagues and five parts of eight, and on the tropics each degree has 

 twenty leagues and four parts of three hundred and sixty, according to the 

 said learned men. 



12. Starting from Cape Verde on a westerly line the terminus three hun- 

 dred and seventy leagues comprises eighteen degrees, inasmuch as the said 

 line or parallel is fifteen degrees distant from the equator, and therefore the 

 degrees each of them contains twenty leagues and five parts of eight, accord- 

 ing to the said learned men. 



13. From Cape Verde to the Grand Canary island are 232 leagues of four 

 miles per league, and it lies from the said Canary on a meridian almost at a 

 third of the " lebeix" or southwestern quarter, and is distant fifteen degrees 

 from the equator, and the middle island of those which lie in front of Cape 

 Verde lies in the quarter of the West towards the Northwest 117 leagues 

 (away), which are equal to five degrees and two-thirds; and from this middle 

 island commences the terminus of the 370 leagues towards the West which 

 terminus is eighteen degrees towards the West from the said middle island, 

 and on that parallel each degree is twenty leagues and five parts of eight, 

 counting 700 stades to a degree, according to the above cited learned men, 

 although Ptolemy uses a different calculation. 



14. And according to Ptolemy, each degree of the equator contains fifteen 

 leagues and two-thirds, and of the tropics fourteen leagues and one-third, and 

 on the parallel of Cape Verde fourteen leagues and two-thirds, and therefore 

 the 370 leagues upon that parallel are understood as extending to the West 

 twenty-five degrees and one-third nearly. 



15. And the Admiral says in his letter that Cape Verde is nine and a 

 quarter degrees distant from the equator. According to Ptolemy, I see him 

 allowing fifteen and two-thirds leagues to a degree ; nevertheless, I decide 

 with the other learned men as to the distance of the said islands from the 

 equator. The division into stades, although the number given by Ptolemy is 

 different from that given by the above cited learned men, Strabo, Alfragano, 

 Macrobi, Teodosi, iind Kuristhenes, they are all essentially in agrément, 

 because Ptolemy makes use of longer stades; so that his 180,000 stades are 

 equal to the 252,000 stades of the above mentioned learned men for the 

 equinoctial line as above said. 



