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LXIII. On the Theory of Storms, with reference to the Views 

 of Mr. Redfield. By Robert Hare, M.D., Member of 

 the American Philosophical Society, Professor of Chemistry 

 in the University of Pennsylvania *. 



1. IVf R. REDFIELD'S idea, that tornadoes and hurri- 

 "*•"■*■ canes are all whirlwinds, involves some improbabi- 

 lities. 



2. It requires that during every hurricane there should be 

 blasts of nearly equal force coinciding with every tangent 

 which can be applied to a circle. Thirty-two ships, equi- 

 distant from the axis of gyration and from each other, should 

 each have the wind from a different point of the compass with 

 nearly equal force. The only modification of which this view 

 of the case admits, is that resulting from the progressive mo- 

 tion which tends to increase the velocity of the wind on the 

 side on which this motion concurs with that of the whirl, and 

 to produce upon the opposite side a corresponding diminution. 

 Moreover, as respects any one station* the chance would be 

 extremely unfavourable that the same hurricane should twice 

 proceed from the same quarter : and yet in the course of time 

 it would be felt, at any station, to proceed from many different 

 directions, if not from every point of the compass. 



3. Mr. Redfield has alleged, that he observed proofs of gy- 

 ration in the effects of the New Brunswick tornado ; but I 

 think that the survey of Bache and Espy shows that it would 

 not be consistent with the facts to suppose such a motion, un- 

 less contingently ; and that it could only be a casual effect of 

 the currents rushing towards the axis of the tornadof. 



4. Being of opinion that calorific expansion is inadequate 

 to explain the afflux of wind towards the equator, it is alleged 

 by Mr. Redfield, " that the space previously occupied by the 

 atmosphere so left behind, is, by the centrifugal action of the 

 earth's rotation, constantly supplied from higher latitudes." 



5. I presume that the meaning of this allegation is, that the 

 centrifugal force communicated to the air at the equator by 

 the diurnal revolution of the earth, lessening the gravity of the 

 air thus affected, causes it to rise, and give place to those por- 

 tions of the atmosphere which, existing where the diameter 

 of the earth is less, have less rotary motion. Admitting an 

 afflux to arise in this way, could it have any other effect than 

 that of accumulating air over the equator, compensating by 

 quantity and altitude for the loss of weight arising from a 

 greater centrifugal force pertaining to that region? But, on 



* Communicated by the Author. 



f See fifth volume of the American Philosophical Transaction's. 



