388 Mr. Redfield's Notice of Dr. Hare's 



share with them any received momentum." The vast disparity 

 of the lateral to the vertical dimensions of a storm, seems to 

 have once attracted the notice of Mr. Espy ; but how this fact 

 can be reconciled with the theory which teaches that a storm is 

 essentially an ascending column of air, I cannot conceive, (par. 

 113.) 



Those are " evidently no transient impulses" which produce a 

 revolving action in storms ; and the effects produced in the at- 

 mosphere by these impulses constitute the proper subject of in- 

 quiry. (^ 114.) No one pretends that the " violence of a hurri- 

 cane" can be " sustained" by the mere " rotary momentum," after 

 the "cessation" of the impelling forces, (par. 115.) 



The ground " taken by Prof. Dove" relating to the calm or 

 cessation of violence which is found on the earth's surface at the 

 axis of a hurricane, quoted in par. 116, and which is deemed 

 "strikingly untenable" by Dr. Hare, is mainly in accordance 

 with direct observations ; as I had formerly shown.* Dr. Frank- 

 lin clearly recognized the absence of any force at the axis of a 

 whirlwind : and the fact having been fully proved by observa- 

 tion, in gales and hurricanes, cannot now be set aside by " stric- 

 tures" on Prof. Dove's language. 



But Dr. Hare thinks he has " demonstrated" in his former ob- 

 jections, in par. 67, that " in extensive whirlwinds ' the fiercest 

 raging' cannot be suddenly interrupted so as to leave a dead calm 

 during the interval which takes place between two opposite 

 winds." (par. 117.) I will now quote the demonstration refer- 

 red to. 



"67. Mr. Redfield alleges, [has shown,] that the storm of August 17th, 1830, 

 whirling to the left, travelled from southwest to northeast at the rate nearly of twen- 

 ty-seven miles [eighteen miZesf] per hour; that its greatest diameter was from five 

 hundred to six hundred miles; that of its severe part was from one hundred and 

 fifty to two hundred and fifty miles. Thus it may be assumed, that in order for 

 an observer to be exposed successively within the severe portion on the south- 

 eastern and northwestern limbs, the storm would have had to move at least one 

 hundred miles, requiring nearly four hours. Hence if the storm in question were 

 a whirlwind, instead of the change having been sudden, several hours would have 

 been required for its gradual accomplishment." 



This singular demonstration appears to consist in the assump- 

 tion, " that in order for an observer to be exposed successively 



* See Prof. Dove's statement at page 333. 

 t See this Journal, Vol. xx, p. 37. 



