816 COSMOS. 



brance of the impression which it has excited in my mind, when 

 I have seen it in the tropics in the calm of nocturnal rest, or 

 ; n the fury of the tempest, have alone induced me to speak of 

 the individual enjoyment afforded by its aspect before 1 

 entered upon the consideration of the favourable influence 

 which the proximity of the ocean has incontrovertibly exer- 

 cised on the cultivation of the intellect and character of many 

 nations, by the multiplication of those bands which ought to 

 encircle the whole of humanity, by affording additional means 

 of arriving at a knowledge of the configuration of the earth 

 and furthering the advancement of astronomy, and of all other 

 mathematical and physical sciences. A portion of this influ- 

 ence was at first limited to the Mediterranean and the shores 

 of south-western Africa, but from the sixteenth century it has 

 widely spread, extending to nations, who live at a distance 

 from the sea in the interior of continents. Since Columbus 

 was sent to " unchain the ocean,"* (as the unknown voice 

 whispered to him in a dream when he lay on a sick-bed near 

 the River Belem) man has ever boldly ventured on ward towards 

 the discovery of unknown regions. 



The second external and general covering of our planet, the 

 aerial ocean, in the lower strata, and on the shoals of which 

 we live, presents six classes of natural phenomena, which 

 manifest the most intimate connection with one another. They 

 are dependent on the chemical composition of the atmosphere, 

 the variations in its transparency, polarisation, and colour, its 

 density or pressure, its temperature and humidity, and its 

 electricity. The air contains in oxygen the first element of phy- 

 sical animal life, and besides this benefit it possesses another 

 which may be said to be of a nearly equally high character, 

 namely, that of conveying sound a faculty by which it like- 

 wise becomes the conveyer of speech and the means of com- 

 municating thought, and consequently of maintaining social 



* The voice addressed him in these words, " Maravillosamwite Dioa 

 hizo sonar tu nombre en la tierra ; de los atamientos de la mar Oceana, 

 que estaban cerrados con cadenas tan fuertes, te dio las Haves" " God 

 will cause thy name to be wonderfully resounded through the earth, and 

 give thee the keys of the gates of the ocean, which are closed with 

 strong chains." The dream of Columbus is related in the letter to the 

 Catholic monarchs of July the 7th, 1603 (Humboldt, Examen critique, 

 i. iii. p. 234.) 



