1 00 Dr. Hare's Additional Objections to 



vol. xx. p. 22.) " It sometimes happens, when the central 

 portion of an extensive storm passes over or near the point of 

 observation, that the comparative calm, or lull which prevails 

 about the apparent centre of rotation is preceded by a gradual 

 rather than a sudden abatement of the wind." " Every expe- 

 rienced navigator will shrink with instinctive apprehension 

 from the very idea of those moments of awful stillness which 

 place him in the central vortex of the hurricane." (Franklin 

 Journal, vol. xix. p. 116, and Silliman's Journal, vol. xx. 



81. Amid the neutralization of evidence which inevitably 

 results from the conflicting statements above quoted, I will 

 endeavour to point out the results which ought to ensue if the 

 inferences of the advocates of the whirlwind doctrine were 

 correct. 



82. When a rotary motion is communicated to a solid by 

 a force applied to any part whatever, the tangential velocity 

 at any point will be directly as its distance from the centre. 

 In a fluid, when the force productive of rotation is applied at 

 any point remote from the axis, the motion at the axis can be 

 no quicker than in the case of a solid, but may be slower, 

 since the parts do not of necessity move simultaneously. In 

 the case of a fluid body kept in motion by a momentum re- 

 sulting from forces previously applied, as in the instance of a 

 Redfield whirlwind, any zone, which has been made to re- 

 volve by the direct application of force, will be retarded until 

 it causes, in the adjoining zones, a due proportionable velo- 

 city. This will not be attained until the whole rotates like a 

 solid. There is however this difference, that the external por- 

 tions of the whirling zone being pressed by the centrifugal 

 force against other portions of the same fluid, the one will 

 conflict with the other, so as to cause the velocity to be com- 

 municated and to lessen outwards from the zone (in which the 

 moving power is or has been applied) till it becomes insensi- 

 ble. This result must ensue the more speedily, since the mo- 

 mentum I'eceives no reinforcement, while the mass which it 

 actuates increases with the square of the distance from the 

 axis. 



83. It follows that at any station over which, or near which 

 the centre of a whirlwind shall pass, there will be a breeze 

 scarcely perceptible at first, but which will strengthen gra- 

 dually into a gale of pre-eminent fury. Subsequently a declen- 

 sion must take place until the centre arrives; here again there 

 would be no perceptible wind. The centre having moved 

 away, the wind must increase again to a maximum of force 

 and then decline to a breeze. 



