OF THE earth's ROTATION ON WINDS. 255 



in astronomy and also in chemistry ; and the old theories 

 long kept possession of the minds of men who^ in their 

 earlier days, were trained to adopt them. Meteorology 

 seems to be at present in a state of transition ; its defects, 

 however, have recently been plainly and strongly cha- 

 racterized by more than one eminent philosopher, it 

 having been said that it was an unintelligible mass, which 

 became less comprehensible the more it was explained ! 

 And this may be truly said of the present popular theory 

 to account for atmospheric disturbances. 



I have, however, attempted to show that the tropical 

 ocean or dry sun-heated land does not cause air to ascend 

 from heated tropical regions to flow over to the polar, and 

 when cooled return to the tropics on the surface, and also 

 that air so passing is not to any palpable extent afiected 

 by the unequal rotation of different latitudes. It has also 

 been proved, by a large amount of reasonable evidence, 

 that all the great atmospheric disturbances are caused by the 

 liberated heat of condensing vapour warming and expand- 

 ing the gases, which are then forced upwards by heavier 

 air, producing ascending currents with horizontal winds to 

 supply them. In this way it has been shown that the 

 trade- winds and monsoons of the tropics and all the more 

 violent winds and storms over certain parts of the ocean, 

 as well as the winds of other parts, are produced. Eva- 

 poration of the small particles of water, which constitute 

 floating cloud, makes the air heavy where that evaporation 

 takes place, when the local air sinks through a Hghter 

 part of the atmosphere to the surface, over which it spreads, 

 creating moderate movements of the air, such as cool 

 breezes. The former disturbances, constituting the great 

 winds, are effects of limited portions of the atmosphere 

 being heated, expanded, and rendered hght, when they are 

 forced into the higher regions. The latter and smaller 

 winds are results of portions of air being cooled and made 



