654 COSMOS, 



heavenly bodies, in the temperature of the air, and in the 

 character of the sea. I have observed these alterations with 

 especial care, and I notice that the mariner's compass (agujas 

 de marear), whose declination had hitherto been north-east, 

 was now changed to north-west ; and when I had crossed this 

 line (ray a), as if in passing the brow of a hill, (como quien 

 traspone una cuesta,) I found the ocean covered by such a 

 mass of sea- weed, similar to small branches of pine covered 

 with pistachio nuts, that we wereapprehensive that, for want 

 of a sufficiency of water, our ships would run upon a shoal. 

 Before we reached the line of which I speak, there was no 

 trace of any such sea-weed. On the boundary line, one 

 hundred miles west of the Azores, the ocean becomes at once 

 still and calm, being scarcely ever moved by a breeze. On 

 my passage from the Canary Islands to the parallel of Sierra 

 Leone, we had to endure a frightful degree of heat, but as 

 soon as we had crossed the above-mentioned line (to the west 

 of the meridian of the Azores,) the climate changed, the air 

 became temperate, and the freshness increased the further we 

 advanced." 



This passage, which is elucidated by many others in the 

 writings of Columbus, contains views of physical geography, 

 observations on the influence of geographical longitude on 

 the declination of the magnetic needle, on the inflection of 

 the isothermal lines between the western shores of the old 

 and the eastern shores of the new continent, on the position 

 of the Great Saragossa bank in the basin of the Atlantic 

 Ocean, and on the relations existing between this part of the 

 ocean and the superimposed atmosphere. Erroneous observa- 

 tions made in the vicinity of the Azores, on the movement of 

 the polar star,* had misled Columbus during his first voyage, 

 from the inaccuracy of his mathematical knowledge, to enter- 

 tain a belief in the irregularity of the spheroidal form of the 

 earth. In the western hemisphere, the earth, according to his 

 views, " is more swollen, so that ships gradually arrive nearer 

 the heavens on reaching the line (ray a), where the magnetic 

 needle points due north, and this elevation (cuestd) is the cause 



* Observations de Christophe Colomb sur le passage de la. Polaire 

 par le Meridien, in my Relation hist. t. i. p. 506, and in the Examen 

 crit., t. iii. pp. 17-20, 44-51, and 56-61. (Compare also Navarrete, in 

 Columbus' Journal of 16th to 30th of September, 1492, pp. 9, 15, 

 and 254.) 



