Strictures on Prof. Dove's Essay. 389 



within the severe portion on the southeastern and northwestern 

 limbs, the storm would have had to move at least one hundred 

 miles." Now it is perfectly clear, that " the southeastern and 

 northwestern limbs" of the severe portion of the storm thus mov- 

 ing " from southwest to northeast," must separately have ad- 

 vanced on two parallel lines, and therefore never could both have 

 been -presented, "successively" or otherwise, to " an observer." 



Besides, the calm or cessation of violence, with the change 

 ensuing from one violent wind to another blowing in an "oppo- 

 site direction," has been known to occur only at or near the cen- 

 ter or axis " of the severe portion" of the storm. This fact, like- 

 wise, renders the supposed demonstration wholly nugatory, even 

 as a "stricture" or criticism. From these and similar comments 

 of Dr. Hare, it would seem to be apparent, that he has acquired 

 no correct apprehensions of the facts and statements thus com- 

 mented upon. (par. 117.) 



To obviate the just objection against the centripetal theory, 

 that " winds blowing from opposite quarters will neutralize each 

 other" Dr. Hare re-alleges the hypothesis that " they are caused 

 by a deficiency of pressure at the axis of the storm producing an 

 upward current for the supply of which they are required ;" thus 

 impliedly resorting, once more, to the erroneous hypothesis of 

 " suction" to draw upward, against the force of gravity, the fast 

 accumulating air, in order to make way for the supposed conflu- 

 ent winds. But let me ask, how can the weight and momentum 

 of all these in-rushing winds be neutralized, without whirling 

 motion, " by a deficiency of pressure at the axis ?" This inward 

 velocity he represents as increasing as the square of the distance 

 passed over, while the successive areas diminish in a like ratio ; 

 but if the velocity be only equable, the aggregate weight and 

 momentum will thus accumulate rapidly from all sides as the 

 areas diminish, and can be turned upward only by equal or great- 

 er forces. Let us suppose " a deficiency of pressure" at the cen- 

 ter of the storm equal to the fall of one inch and a half in the 

 barometer, with a centripetal wind of eighty miles an hour ; how 

 many seconds would be required to increase the central pressure 

 to an extent never before known? (par. 118.) 



It is stated here that " after the base of the ascending column 

 is reached, evidently the horizontal afflux must be superseded by 

 a vertical movement," and "hence about the centre of the space 



