18 On the prevailmg Storms of the Atlantic Coast. 



electrical agency, serves rather to retard than to advance our knowl- 

 edge of nature. 



Rarefaction, occasioned by an increase of temperature, has also 

 been adduced as the immediate agent in producing storms ; but, to 

 say nothing of the difficulty of proving an extraordinary increase of 

 temperature before a storm, it has been justly remarked by Dr. 

 Hare, that " the air, being a perfectly elastic fluid, its density is de- 

 pendent on pressure as well as on heat, and it does not follow that 

 air, which may be heated in consequence of its proximity to the earth, 

 will give place to colder air from above. The pressure of the at- 

 mosphere varying with the elevation, one stratum of air may be as 

 much rarer by the diminution of pressure consequent to its altitude, 

 as denser by the cold consequent to its remoteness from the earth ; 

 and another may be as much denser by the increased pressure aris- 

 ing from its proximity to the earth, as rarer by being warmer. 

 Hence, when unequally heated, different strata of the atmosphere 

 do not always disturb each other." 



It is, indeed, the prevailing opinion that change of temperature, is a 

 principal cause of those extensive currents or revolutions of the earth's 

 atmosphere which we distinguish as trade winds, monsoons, &ic. ; and it 

 is to the operation and effect of these great and regular moving masses 

 or currents, that we are disposed mainly to ascribe the more active 

 and striking meteorological phenomena which occur in every latitude. 

 But whether this be admitted or not, it must be evident, that to as- 

 cribe the occurrence of storms and hurricanes chiefly to change of 

 temperature or rarefaction, in a particular locality, whether in the 

 tropical or temperate latitudes, is falling into as great an error as if 

 we were to ascribe the tides of the bay of Fundy, or the coast of 

 Patagonia, to the specific attraction of the heavenly bodies on those 

 localities. Indeed, the analogy between the tides and currents of 

 the ocean, and of the atmosphere, is perhaps sufficient for our argu- 

 ment, for as the great serai-diurnal swell, or tide wave of the ocean, 

 is brought to bear with concentrated eflect upon its smaller portions, 

 or tributaries, so do the massive currents or tides of the atmosphere 

 often press with corresponding energy upon its more detached por- 

 tions, while seeking to restore the gener;;l equilibrium. We have 

 the full effects of heat and rarefaction exhibited on nature's grandest 

 scale, between the tropics, acting jointly with other causes, and the 

 aggregate and uniform result, is only that of a regular and moderate 

 breeze or trade wind, and an equable state of the barometer. To 



