WINDS. 



397 



The natural course of vapor is then from the east to the west — con- 

 sequently, the vapor from the oceans, seas, and lakes, which lie to the 

 east, supply the vapor or moisture to the land on the west ; — hence it 

 follows that the continent of North and South America receives its 

 great supplies of rain from the North and South Atlantic Ocean, while 

 Asia, Europe, and Africa derive theirs from the Pacific and Indian 

 Oceans, and inland seas. 



The particles of vapor move over each other without friction, and 

 vapor is impelled by the law of its distribution from the Equator 

 towards the Poles. It meets with resistance in the atmosphere, 

 whether the latter is at rest or in motion. If the course of the wind 

 coincides with the direction of the vapor under its own pressure, it 

 will be accelerated ; but if adverse, it will be somewhat retarded. 

 Nevertheless, it would seek to distribute itself agreeably to its own 

 laws, from the Equator towards the Poles, for the purpose of main- 

 taining the equilibrium. 



The law by which vapor disseminates itself is in direct opposition 

 to what the currents of air are known to follow, viz. : from the warmer 

 areas to the colder ones, instead of the reverse. We are not aware of 

 the great flow of vapor, as it passes almost in an invisible state, and 

 is not developed until the temperature is so far decreased as to cause 

 condensation, when it becomes evident in the form of clouds, fog, &c. 



It has been shown satisfactorily that the atmosphere cannot carry 

 any heat to the Poles, if the upper current did exist. Therefore, it 

 can have no influence in ameliorating the climate there. But with 

 vapor it is different. It carries its heat in a latent form, and retains 

 it till it reaches the areas where it is required, and there it is given 

 out by condensation. This, we think, moderates the cold of the 

 northern and southern hemispheres. 



It is almost impossible to obtain by experiment the height at which 

 vapor exists. I have made many attempts to ascertain the height of 

 the vapor plain by the vegetation, which varies in different latitudes 

 from 1200 to 4000 feet. Whether it maintains a constant position, 

 has not yet been determined ; but that it does so, is very probable. 

 In calms and during easterly winds, high peaks or mountains are seen 

 capped with clouds, which mark the vapor plain. These are only 

 observed in calms or easterly winds. With westerly winds, their out- 

 line is clear and well defined, — another proof, if it were wanting, of 

 the flow of vapor from the east to the west. 



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