266 PHYSICAL GEOGRAPHY OF THE SEA, AXD ITS METEOROLOGY. 



eye from aloft look down upon the scene, the upper side of the 

 cloud stratum would present somewhat the appearance of an immense 

 caldron, boilmg, and bubbling, and intumescing in the upper air. 

 These huge bergs condense the vapoiu", and the liberated heat causes 

 the an above them to swell out, and to stand like so many curiously- 

 shaped fimgi above the general cloud level. And thus, where the 

 icebergs are thick, the clouds are formed low dovai. Icebergs, like 

 islands, facihtate the formation of clouds and promote precipitation. 

 514. Tm-n we now to the equatorial cloud-ring. Seafaring 

 The horse latitudes peoplo havo, as if by common consent, divided the 

 —the doldrums. occan off iiito icgions, and characterized them ac- 

 cording to the winds ; e. g., there are the " trade-wind regions," the 

 "variables," the "horse latitudes," the "doldrums," etc. The 

 "horse latitudes" are the belts of calms and hght airs (§ 210) 

 which border the polar edge of the north-east trades. They were 

 so called from the cncumstance that vessels formerly bound from 

 New England to the West Indies, mth a deck-load of horses, 

 were often so delayed in this calm belt of Cancer, that, for the want 

 of water for then- animals, they Avere compelled to thi^ow a portion 

 of them overboard. The " equatorial doldrmns " is another of 

 these calm places (§ 212). Besides being a region of calms and 

 baffling ^Aonds, it is a region noted for its rains and clouds, which 

 make it one of the most oppressive and disagreeable places at sea. 

 The emigrant ships from Em-ope for Austraha have to cross it. 

 They are often baffled m it for two or tln'ee weeks ; then the 

 cliildren and the passengers who are of deHcate health suffer most. 

 It is a frightful graveyard on the wayside to that golden land. A 

 vessel bound into the southern hemisphere from Em'ope or x\merica, 

 after clearing the region of variable wids and crossing the " horse 

 latitudes," enters the north-east trades. Here the mariner finds 

 the sky sometimes mottled with clouds, but for the most part clear. 

 Here, too, he finds his barometer rising and failing under the ebb 

 and flow of a regular atmospherical tide, which gives a high and low 

 barometer every day with such regularity that the hour within a few 

 minutes may be told by it. The rise and fall of this tide, measm'ed 

 by the barometer, amounts to about one tenth (0.1) of an inch, 

 and it occm's daily and everj^vhere between the tropics : the maxi- 

 mum about lOh. 30m. a.m., the minimum between 4h. and 5h. p.m., 

 with a second maximum and minimum about 10 p.m. and 5 a.m.* 



* See paper on Meteorological Observations in India, by Colonel Sykes, Philo- 

 sopliical Transactions for 1850, part ii., page 297. 



