72 PHYSICAL GEOGRAPHY OF THE SEA. 



calm. Hoar-frost is nothing bvp congealed dew, and owes its 

 formation to the same causes. 



When warmer air-currents are cooled by being transported 

 into colder regions, or from any other refrigerating cause, a great 

 part of their moisture generally condenses into small vesicles, 

 but very little heavier than the surrounding atmosphere, 

 which then becomes visible under the form of clouds, those 

 great beautifiers of our changing skies, that frequently trace 

 such picturesque, gorgeous, or singular groups and landscapes 

 in the aerial regions. The inhabitants of countries where the 

 heavens are monotonously serene, may well envy us the charms 

 of a phenomenon which in some measure affords us compensa- 

 tion for so many disagreeable vicissitudes of the weather. Who 

 that has admired at sunset the light clouds so beautifully fringed 

 with silver and gold, or glowing with the richest purple, and 

 loves to follow them in all their wonderful and fantastic trans- 

 formations, will deny that they are the poesy and life of the skies, 

 the awakeners of pleasing fancies and delightful reveries ? 



Thin wreaths of clouds have been observed, by travellers that 

 have ascended the most elevated mountains, floating high above 

 the peak of Chimborazo or Dhawalagiri, and thus shows us to 

 what an amazing altitude the emanations of ocean are carried 

 by the ascending air-current. 



Sometimes when light clouds pass into a warmer atmosphere, 

 they gradually dissolve and vanish ; more frequently the accu- 

 mulating moisture, too heavy to continue floating in the air, or 

 condensed by electrical explosions, descends upon the earth in 

 rain, which, with few exceptions, visits every part of the globe, 

 either in its liquid form or congealed to snow or hail. But the 

 quantity of rain which annually falls in different regions is very 

 unequal, and strange to say, it is not most considerable in those 

 countries whose climate enjoys an unenviable notoriety for its 

 clouded atmosphere and the great number of its rainy days. 

 In the tropical regions it is generally only about the time of the 

 summer solstice that abundant showers of rain fall regularly every 

 afternoon, while the rest of the year, the sky is uninterruptedly 

 serene ; but during the short period of the rainy season, a far 

 greater quantity of water is precipitated upon the earth, than 

 in the temperate zones. 



While on the island of Guadaloupe, the annual quantity of 



