THE WIXDS OF THE SOUTHERIT HEMISPHEBE. 427 



sary to bring clo^^vn tlie 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. Com- 

 puting 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 yearly amount 

 of 1368.7 inches. Neither the Cape Horn rains, nor the rains any- 

 where at sea on the polar side of 45° S., are periodical. They are 

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

 at others, but abundant at all. 



828. Now, considering the extent of water surface on the polar 

 Influence of highlands side of the south-cast trado-wiud belt, we see no 

 upon precipitation, reasou why, ou tlicse parallels, the engirdling air of 

 that great watery zone of the south should not, entirely around the 

 earth, be as heavily charged with vapom* as was that which di'opped 

 this flood upon the Patagonian hills. If those mountains had not 

 been there, the condensation and the consequent precipitation would 

 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 condensa- 

 tion and the liberation of its latent heat ; and we make, as we shall 

 proceed to show, no violent supposition, if, in attempting to explahi 

 this activity of circulation south of the equator, we suppose a cloud 

 region, with a combination of conditions in the antarctic circle 

 peculiarly favourable to heavy and almost incessant precipitation. 

 But, before describing these conditions, let us turn aside to in- 

 quu'e 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. If we take a measure, as a cubic foot, of ice at zero, and 

 The latent heat of ^pply heat to it by mcaus of a steady flame that will 

 vapour. gj^g Qg- ]^g^^ ^^ ^ uniform rate, and in such quantities 

 that just enough heat may be impai'ted to the ice to raise its tem- 

 peratm-e 1° a minute, we shall find that at the end of 32 minutes 

 the ice wiU be at 32^. The ice will now begin to melt ; but it 

 and its water, the heat being continued, will remain at 32° for 

 140 minutes, when all the ice mil have become water at 32°.t 

 This 140° of heat, which is enough to raise the temperature of 140 



* Eeport of the British Association for 1852, p. 256. 

 t See Espy's Philosophy of Storms. 



