PRESSURE IN THE AIR, 281 



from equality to inequality ; from radiation 

 equally every where, to projection unequally 

 somewhere. Is it not legitimate to conclude, 

 that it is owing to the unresisting state of the 

 upper regions of the firmament, that the whole 

 column of the atmosphere progressively de- 

 creases in density, in consequence of increased 

 dilatation ; that while the expansion of the upr 

 per strata takes place, a, progressive diminu- 

 tion of pressure from the top to the bottom, 

 throughout the whole atmospheric column, will 

 be the inevitable consequence, similar to a 

 small portion of air, enclosed in a large bladder, 

 under the exhausted receiver of an air pump ; 

 insomuch, that the pressure of the air, near the 

 surface of th^ earth, will be less in degree side- 

 ways, and downwards, than it will be perpen- 

 dicularly upwards. 



Instead of agreeing to the opinions which 



now prevail, that the different strata of the 



atmosphere increase in weight from top to 



bottom, in a manner similar to a quantity of 



fine carded wool, piled up and thrown into a 



deep pit; the lower strata carrying the weight 



of the upper, and being compressed by them ; 



the actual condition of the atmosphere is the 



very reverse of this ; the density which the 



wool possesses, with relation to the rarity of the 



medium in which it is situated, gives it weight ; 



insomuch, that every particle of the wool 



