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NEW YORK, June 13, 



The Tornado: Theories; Objec- 

 tions. B. A. Hazen 35: 



Mental Science. 



Motor Hallucinations 35( 



Color- Vision and Color-Blindness 35' 



Notes and News 35' 



On the Group op Meteorites re- 

 cently discovered in Bren- 

 HAM Township, Kiowa County, 



CONTENTS : 



Letters to the Editor. 



The International Congress of 

 Geologists. J. P. Lesley ; 



Counting Bacteria. M. D. Ewell < 



Triple Rainbow. Solon I. Bailey : 

 Book-Reviews. 



Pictorial Africa ; 



Henry M. Stanley I 



Han. . George F. Kunz 359 1 Among i 



: Publishers . 



THE TOENADO: THEOEIES; OBJECTIONS. 



[Continued from p. 356.] 



Professor Davis says, further, " It is a mistake to say that 

 the latent heat, when liberated, will warm the air enough to 

 allow the condensed vapor to evaporate again ; for the latent 

 heat is completely expended in the vrork of pushing away the 

 air that surrounds the ascending expanding mass, and there- 

 fore cannot be applied to any other task. Espy made this 

 error for a time, but afterwards corrected himself. It is re- 

 grettable to see the error now revived by Hazen." I am 

 sure no one could ask for a stronger confirmation of bis 

 views than this from an opponent. If the above argument 

 amounts to any thing, it declares that the latent heat of con- 

 densation would certainly immediately re-evaporate the 

 moisture, unless it were used up in performing work. If it 

 is used for this purpose, it certainly and most emphatically 

 cannot be used for causing a rarefaction in the cloud, and 

 for increasing the energy of the tornado. Professor Davis 

 is entirely wrong in his allusion to Espy. I am inclined to 

 think that even Espy, with all his disadvantages, was too 

 well informed to adopt such a doubtful and visionary idea as 

 this of e£Pective work performed in the free upper air. There 



is not one scintilla of evidence that he ever considered this 

 question, except, possibly, to deny that any thing of the 

 kind was to be thought of. 



I challenge Professor Davis, or any one else, to show by 

 Espy's writings that he disposed of any of his heat on this 

 hypothesis, or that he ever thought that the latent heat would 

 re-evaporate the moisture. He very quickly saw that the 

 liberation of so much latent heat as his theory called for 

 would heat up the air enormously, and was forced to dispose 

 of it by radiation into space. It is probable that the amount 

 of energy made effective by this so-called "work" in the 

 free upper air is infinitesimal as regards the development of 

 force. The explosions that Espy made in his nephelescope 

 caused the air to rush v^ith a velocity of perhaps a thousand 

 feet per second. This enormous velocity caused a sufficient 

 cooling to produce a cloud, which, however, was quickly 

 evaporated. All reliable experiments have shown that the 

 expansion of saturated air at velocities probably at least ten 

 times as great as can ever occur in nature does not produce 

 any cloud ; and we see the reason for this in the fact that 

 the latent heat made sensible does not permit the formation 

 of cloud, for the condensing moisture is re-evaporated before 

 it becomes visible. 



It is a very significant fact, and one that has been borne 

 in upon me with no little force by conversation with others, 

 that Ferrel has introduced a long general discussion of this 

 question of work performed by expanding air in his two 

 lastest treatises, but has nowhere made this theory available, 

 or even discussed it, in connection with the generation of 

 storms or tornadoes. It would seem as though the amount 

 of effective energy ought to be computed very closely, and 

 its proper place given it. It is probable that an ascending 

 cylinder of air a hundred miles in diameter would not pro- 

 duce any effective energy or any expenditure of heat in its 

 centre from this cause. * I am inclined to think that the 

 total energy that can ever be developed from an ascending 

 mass of saturated air is no whit greater than what may be 

 called the balloon effect. If a hot-air balloon rises in the air 

 at the rate of ten feet per second, it has carried a certain 

 weight, say three thousand pounds, to twenty thousand feet, 

 and there we have potential energy; but, if the balloon de- 

 scends at thfe same rate, there will be no display of extraor- 

 dinary force. If, instead of the confined mass of enormously 

 heated air, we had a mass of air heated a few degrees above 

 the surrounding air, it would rise; but here the air would 

 spread over a great space, and we would not have the con- 

 centrated potential energy that we had in the balloon. To 

 say that this air had any power of producing effective en- 

 ergy, or even to say that it could have arisen at all without 

 the corresponding descent of nearly an equal amount of 

 cooler air, is highly problematical. 



4, 5. G-YRATIONS IN THE UpEUSHING AiR AND A "VIOLENT 



Inrush. — We have already seen that the evidence for these 

 gyrations is exceedingly contradictory, and the weight of 

 evidence is overwhelmingly against them. It would almost 

 seem as though this theory were introduced to avoid a seri- 

 ous difficulty ; at all events, we hear nothing of it for nearly 

 forty years after the first studies. It is plain that a partial 

 vacuum, if there were one, would be filled at once by the 

 air rushing from all sides. Has this theory been invented to 

 provide a whirling mass having sufficient consistency to keep 



