214 THE INFLUENCE OF SUK-HE4TED LAND, ETC. 



from the Southern Indian Ocean to the Himalayas. At 

 present, in the summer monsoon of the Indian Ocean, vapour 

 passes from Madagascar to the Himalaya Mountains — from 

 north to south, through sixty degrees of latitude, and it 

 might equally well pass over the tropical Atlantic to northern 

 mountains. This would prove, by the evidence of new facts, 

 that direct solar heating within the tropics did not cause the 

 air to swell and ascend — and flow over in the higher regions 

 towards the poles. The tropical lands would then be more 

 heated by the direct solar rays than they are now, but air 

 would no more rise from them than it does at present from 

 the deserts of Arabia and Africa. 



Without further adverting to local modifications of winds, it 

 is conceived that we are authorised to conclude that sun-heated 

 surfaces of land do not produce ascending atmospheric currents 

 which overflow in the higher regions to distant colder parts. 



