THE SOURCE OF THE NILE. $7 



ftru&ing the neceffary instruments for navigation. He cor- 

 rected the folar tables of the Arabs, and made fome altera- 

 tions in the aftrolabe : For, ftrange to tell ! the quadrant 

 was not then known in Portugal, though, a hundred years 

 before, Ulughbeg had meafured the fun's height at Sa- 

 marcand in Perfia, with a quadrant of about 400 feet radi- 

 us, the largeft ever conflructed, if, indeed, the iize of this 

 be not exaggerated. 



Henry, who, by his liberality and affability, had drawn 

 together the moil learned mathematicians and ableft pilots 

 of the age, now propofed to reduce his fpeculations to prac- 

 tice. Many mips had failed in the courfe of his difquifi- 

 tions, and ten years had now elapfed before the prince, af- 

 ter all his encouragement, could induce the captains to pro- 

 ceed farther than Cape Non, or, thirty leagues further, to 

 Cape Bojador. To this their courage held good ; after which, 

 the fear of fiery oceans reviving in their minds, they returned 

 exceedingly fatisiied with their own perfeverance and abili- 

 ties. Henry, though greatly hurt at this behaviour, diffem- 

 bled the low opinion which he had formed of both. He 

 contented himfelf with propofing to them different reafons 

 and rewards ; and urged them ■ to repeat their voyages, 

 which, however, constantly ended in the fame difappoint- 

 ment. And it is probable a much longer time might have 

 been fpent in thefe mifcarriages, had not accident, or rather 

 providence, flept in to his afiiftance. 



John GonsAlez and Triftan Vaz, two gentlemen of his 

 bed-chamber, feeing the impreffion this behaviour had 

 made on the prince, and having obtained a fmall fhip from 

 him, refolved to double Cape Bojador, and difcover the coaft 



Vol. II, N beyond 



