THE WINDS OF THK SOUTHERN HEMISPHERE. 443 



rnptly out of the sea, or separated from it only by lowlands — 

 that seems to be necessary to bring down the rain in such floods. 

 Colonel Sykes* quotes the rain-fall of Cherraponjie at 605.25 

 inches for the 214 days from April to October, the season of the 

 south-west monsoons. Computing the Cape Horn rains according 

 to the ratio given by King and Fitzroy for their 41 days of 

 observations, we should have a rain-fall in Patagonia of 825 

 inches in 214 days, or a J'early amount of 1368.7 inches. 

 Neither the Cape Horn rains, nor the rains anywhere at sea on 

 the polar side of 45"^ S., are periodical. The}^ are continuous ; 

 more copious, perhaps, at some seasons of the year than at 

 others, but abundant at all. 



828. Influence of higJdands upon precipitation. — Now% considering 

 the extent of water surface on the polar side of the south-east 

 trade-wdnd belt, we see no reason why, on these parallels, the 

 engirdling air of that great watery zone of the south should not, 

 entirely around the earth, be as heavily charged w4th vapour as 

 was that which dropped this flood upon the Patagonian hills. If 

 those mountains had not been there, the condensation and the 

 consequent precipitation w^ould probably not have been as great, 

 because the conditions at sea are less apt to produce rain ; but the 

 quantity of vapour in the air would have been none the less, 

 which vapour was being borne in the channels of circulation 

 towards the antarctic regions for condensation and the liberation 

 of its latent heat ; and we make, as we shall proceed to show, no 

 violent supposition, if, in attempting to explain this activity of 

 circulation south of the equator, we suppose a cloud region, with 

 a combination of conditions in the antarctic circle jDCCuliarly 

 favourable to heavy and almost incessant precipitation. But, 

 before describing these conditions, let us turn aside to inquire 

 how far precipitation in the supposed cloud region of the south 

 may assist in giving force and regularity to the winds of the 

 southern hemisphere. 



829. The latent heat of vapour. — If we take a measure, as a cubic 

 foot, of ice at zero, and apply heat to it by means of a steady 

 flame that will give off heat at a uniform rate, and in such quan- 

 tities that just enough heat may be imparted to the ice to raise 

 its temperature 1° a minute, we shall find that at the end of 

 o2 minutes the ice Avill bo at 32°. The ice will now begin to 



* Report of tlie British Association for 1852, p. 25G. 



