30 CANARY ISLANDS. 



ratiire of the interior of the globe in different latitudes. 

 But it has been proved by experiments, that the tempera- 

 ture of the sea, at great depths, diminishes in a constant 

 progression ; from which fact, some philosophers have 

 maintained that the bottom of the ocean is actually a bed 

 of ice. But, unfortunately for them. Count Rumford has 

 shown by experiment, that ice is always formed at the sur- 

 face of the water, and that, except to a certain extent 

 within the polar regions, it cannot exist at the bottom of 

 the ocean. 



Intensity of the Color of the Sky. — In travelling 

 from the higher latitudes to the torrid zone, I have re- 

 peatedly observed an increase of the azure tint of the sky, 

 and in the same parallel, fainter at sea than when on land. 

 The latter circumstance is owing to the quantity of aque- 

 ous vapor which is constantly rising from the ocean to the 

 upper regions of the atmosphere. Hence, in all latitudes, 

 the intensity of the color of the sky diminishes from the 

 zenith to the horizon, and this nearly in arithmetical pro- 

 gression. 



Color of the Sea. — The color of the sea varies very 

 much in appearance, but it is generally of a deep, bluish- 

 green, which becomes less intense as we approach the 

 coasts. This apparent color of the sea may be attributed 

 to the same causes that impart the blue shade to the dis- 

 tant mountains, and to the sky its azure hue. The other 

 shades in the color of the sea, depend on causes which 

 are local, and som.etimes illusory. It is said that the Medi- 

 terranean, in its upper part, sometimes assumes a purple 

 tint. In the Gulf of Guinea, the sea has a whitish ap- 

 pearance, and around the Maldive Islands, it is black. 

 The Vermeille, or Vermillion Sea, near California, has 

 received its name from the red color which it bears. I 

 have observed a phenomenon similar to the latter about 

 the coast of Florida. 



Humboldt observes, in his travels from Spain to South 

 America, that in fine calm weather, the color of the sea 

 was found to be equal to 33°, 38°, and sometimes 44° of 

 Saussure's cyanometer, although the sky was very pale, 



