THE S6URCE OF THE NILE. 97. 



flru(?ling the neceflary inftruments for navigation. He cor- 

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

 tions in the ailrolabe : 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 Pedia, with a quadrant of about 400 feet radi- 

 us, the largeft ever confl:ru(5ted, if, indeed, the fize of this 

 be not exaggerated. 



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

 together the moil learned mathematicians and ablcil pilots 

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

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

 tions, and ten years had now elapfcd 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 fatisfied with their own perfcverance and abili- 

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

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

 contented himfelf with propoling to them different reafons 

 and rewards ; and urged them to repeat their voyages, 

 which, however, conftantly ended in the fame difappoint- 

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

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

 providence, ftept in to his affillance. 



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 lliip from 



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



Vol. II, N beyond 



