310 Mr. RedfieWs Reply to Dr. Hare. 



eastward," or "nearly at right angles" to its first course; accord- 

 ing to the descriptions and plan of Prof. Bache, who gives the 

 course of the axis as " east 10° N.," the building being to the 

 southward or on the right of this line. 



I say nothing here of the protection afforded by -'an edifice" 

 which after the first moment, according to the hypothesis of mo- 

 tion adopted by Messrs. Espy and Hare, was constantly more or 

 less to leeward of the building so protected. By applying to 

 Prof. B.'s plan, as before, a compass card, moved from west to east 

 without revolving, we shall find their wind to commence nearly 

 at east, passing thence through south to southwest, and possibly 

 to west southwest, near which it would terminate. Thus, the 

 first effects of the wind, when, even upon the hypothesis of "suc- 

 tion," the building was unprotected, could not produce ihe first 

 motion in the direciion " to the west of north," which may per- 

 haps be fairly taken at 5° or 10° west of north; and the wind, 

 on their hypothesis, would hardly appear to have reached a point 

 which could produce the second movement "to the east." 



I have been thus particular in this examination, because the case 

 thus alleged by Dr. Hare is a further specimen of the erroneous 

 inductions which have been made and relied on by my opponents. 

 In examining the plans referred to, it should be observed, that 

 the sketch of prostrations in the orchard, which is included in 

 fig. 3, is evidently on a more reduced scale than that given in the 

 plan of the building ; otherwise, the buildings must be of size 

 suflicient nearly to have covered the orchard. This change of 

 scale may cause some confusion unless particularly noticed. 



That the velocity and consequent force of the whirling move- 

 ment of the tornado is maintained by the direct pressure of the 

 surrounding atmosphere, rather than by the " suction" alleged by 

 Dr. H. I can readily conceive; but that the "impulse of a whirl- 

 wind" of this charaeter is generally found to be " tangential" to 

 its axis, which he seems to consider a necessary condition, I do 

 not admit. 



Dr. Hare appears to concede, that my survey of this tornado 

 shows effects which accord with whirlwind action ; but he seems 

 desirous of limiting this admission to the prostration of " certain 

 trees," and alleges that this survey " does not demonstrate gyra- 

 tion to be an essential feature of tornadoes," and that " it is suffi- 

 ciently accounted for by considering it as a fortuitous consequence 



