138 Strictures on Dove's Essay "On the Law of Storms." 



the diversity of the velocity of the earth's surface, at different 

 distances from the equator, operating upon a wind blowing from 

 one parallel of latitude to another. I am however unable to un- 

 derstand how any difference of momentum, thus arising, can act 

 throughout all parts of a circle upon an elastic fluid, so as to sus- 

 tain the equability of motion requisite to enduring gyration. It 

 seems to me that the influence of the terrestrial motion can ope- 

 rate harmoniously neither upon each quadrant, nor each zone of a 

 circle. The effect upon the south limb cannot, I think, coope- 

 rate with that upon the northern one. 



101. Moreover, as the velocities of the aeriform particles in a 

 whirlwind must be greater as they are farther from their axis, I 

 do not see how a uniform force operating upon particles requiring 

 such various velocities, can produce movements which can har- 

 monize in causing a non-conflicting rotation of the whole mass. 



102. How can this process avail to produce a revolution in the 

 same direction in all the storms of this quarter of the globe, as al- 

 leged by Mr. Redfield and sanctioned by the author, when, agree- 

 ably to the most ample and satisfactory evidence adduced by Prof. 

 Loomis, as well as general experience, some of the most violent 

 storms of this continent travel from the northwest towards the 

 southeast. In such cases, on account of its blowing obliquely 

 towards or from the equator, the wind would change its position 

 relatively thereto, only with a portion of the speed which is as- 

 sumed in the calculation of Prof. Dove, and when the change of 

 position should be in an opposite direction from that which he 

 supposes, would it not cause the storm to whirl in the opposite 

 way ? 



103. Prof. Dove in the second paragraph, page 211, employs 

 the following language : " As the West India hurricanes origin- 

 ate at the inner boundary of the trade winds, where, at the so 

 called region of calms, the air ascends and flows over the trade 

 in an opposite direction ; it is probable that portions of this upper 

 current, penetrating through the lower one, can give the first 

 occasion of those storms. The high mountains of several of the 

 islands, by offering a mechanical impediment, may be one cause 

 of this effect, as the airflows with redoubled violence between two 

 mountains." 



104. Prof. Dove here alleges that the upper current may pene- 

 trate the lower, but does not say why it should do so. Where- 



