200 THE INTELLECTUAL RISE IN ELECTRICITY. 



of my opinion, I revert to the arguments which I have de- 

 tailed respecting the line which passes from north to south 

 one hundred leagues west of the Azores; for, in sailing 

 thence, westward, the ships went on rising smoothly 

 towards the sky, and then the weather was felt to be 

 milder, on account of which mildness the needle shifted 

 one point of the compass ; the further we went the more 

 the needle moved to the northwest, this elevation produc- 

 ing the variation of the circle which the North star de- 

 scribed with its satellites." 



The denial of credit to Columbus for the actual discov- 

 ery of variation depends chiefly upon the supposed indica- 

 tions of the 1436 chart of Andrea Blanco or Bianco (see 

 note, page 197) and in a general way upon inferences that 

 earlier navigators may have observed the same behavior 

 of the needle. 



Humboldt 1 states that three places in the Atlantic line 

 of no variation for September I3th, 1492, May 21, 1496, 

 and August i6th, 1498, can be certainly determined, and 

 that the line at that time ran from northeast to southwest, 

 touching the South American coast a little east of Cape 

 Cordova. That distinguished scientist, however, summed 

 up the achievement of Columbus in the words : u The re- 

 discoverer of the New World found a line of no variation 

 3 west of the meridian of the Island of Flores, one of the 

 Azores," 2 and elsewhere explicitly says that he has no 

 right to the title of discoverer of the variation itself. But 

 then, Humboldt, who as the foregoing quotation shows, 

 was equally averse to according to Columbus the greater 

 honors which the world's opinion now freely bestows upon 

 him, appears to have based his conclusion upon the show- 



. Critique de 1'Hist. de la Ge"og., vol. iii., p 44-48. Cosmos, 

 i., 169-197; v., 49-60. 



2 He also says (Cosmos, v. 54) that Columbus "had the great merit of 

 determining astronomically the position of a line of no variation 2 l / 2 

 east of the Island of Corvo in the Azores on the I3th of September, 

 1492." 



