66 



SCIENCE. 



[Vol. XVII. No. 417 



ease is the alliance with this bacillus of pneumococcas, which also 

 lives in Russian marshes, river-miid. and village pools. 



Hunger and Infection. 



It is a well-known fact, says the Medical Press, that hunger 

 predisposes to certain diseases, but it has been reserved to two 

 Turin doctors to demonstrate the increased liability experimentally. 

 Their observations were carried out with the virus of bacillus 

 anthrax on pigeons,— a disease to which these birds are, under 

 ordinary circumstances, refractory. They found, however, that 

 six days' total deprivation of food rendered the birds amenable to 

 the virus, on condition that food was still withheld. If, however, 

 food was given at the same time as the virus, then they still suc- 

 cessfully resisted infection. Further, when starvation was con- 

 tinued for two days after the inoculation, and food then given, the 

 derelopraent of the disease, though not prevented, ran a slower 

 course. Lastly, the virus proved capable of infecting birds well 

 fed up to the date of inoculation, but starved subsequently. The 

 line of investigation is evidently one which admits of further 

 research, but the moral is obvious. 



LETTERS TO THE EDITOR. 



*** Correspondents are requested to be as brief as possible. The writer's name 

 is in all cases required as proof of good faith. 



The editor will be glad to publish any queries consonant with the character 

 of the journal. 



On request, twenty copies of the number containing his communication will 

 be furnished free to any correspondent. 



Cyclones and Areas of High Pressure. 



Iij his communication to Science of Jan. 16, Professor Perrel 

 speaks of my storming a camp in which he was not to be found. 

 This I cannot consider entirely wasted effort, since it has enabled 

 me to more exactly formulate the position which he does occupy. 

 I, however, do not like the simile, for I am sure I can speak for 

 Professor Davis when I say that we are not enemies trying to 

 knock down, undermine, or even disparage Professor Ferrel's 

 work; neither are we partisans whose duty, as Mr. McAdie ap- 

 pears to think, is to look with special favor upon views promul- 

 gated by our own countrymen, and with corresponding disfavor 

 upon views of foreigners. We are merely scientific men, trying, 

 with the best knowledge we can command, to determine the truth 

 about a matter which certainly admits of a difference of opinion. 

 I did not set out with the ambitious task of stating a new theory 

 which was to stand out as a rival to the life-work of Espy and 

 Ferrel, but merely to quote certain facts which to me indicate 

 that the present theory of cyclones as commonly understood needs 

 modification. As a result of my reading and continuous observa- 

 tion of weather-maps, I frequently frame new hypotheses to en- 

 able me to more closely follow and anticipate the phenomena that 

 are presented to me. Some of these I stated in my last communi- 

 cation, rather hoping that the criticism of Professor Ferrel's well- 

 stored mind would enable me to gain more light on them. 



Had not Ferrel so warmly espoused the condensation theory, I 

 should not have thought this an essential part of his own. Is it 

 not Espy's theory, rather than Ferrel's, that needs reconsideration? 

 Ferrel's work has been in showing the effect of the earth's rota- 

 tion on atmospheric currents, and, it seems to me, is unassailable. 

 He has shown more convincingly than any other writer the pos- 

 sibility of the existence of dynamic gradients as distinguished 

 from thermic gradients ; and we find Teisserenc DeBort calculat- 

 ing by Ferrel's formula how much of each cyclone is to be at- 

 tributed to thermic and how much to dynamic gradients, and 

 even going so far as to show that cyclones may exist in which 

 there is only a dynamic gradient, the thermic gradient having dis- 

 appeared. In his last article in Science, Professor Ferrel, in 

 speaking of low temperature as a cause of high-pressure areas, 

 says, •■ While I regard this as adequate to account for it, I have 

 never said or thought that it is the only cause, but simply the 

 principal cause. I think there are other causes, especially in the 

 origin oi these high-pressure areas." 



In speaking of the case referred to by me of a long trough of 

 low pres3ure becoming nearly circular by the increase of pressure 



at both ends, he says, "I do not say that i^ such a case there 

 would not be a certain very small amount or gyratory movement 

 produced by the air flowing into the trough while it was filling 

 up. as it would be at once if there were no restraining force to 

 keep the air from the high pressure on each side from rushing 

 in.'' 



But Professor Ferrel wUI say these are only secondary effects, 

 and there must be an originating and sustaining force behind 

 them. This he finds in differences of temperature in adjacent 

 bodies of air. even admitting that cyclones of moderate power 

 may exist without precipitation. 



I do not think any one who has entered into this discussion, 

 unless it be Professor Hazen, has doubted that differences of tem- 

 perature resulting from solar energy is the ultimate power from 

 which all cyclonic and anticyclonic phenomena are derived. I 

 stated as clearly as I could, in my last article, that differences of 

 temperature between pole and equator, ocean and continent, 

 were, in my opinion, the ultimate cause of differences of pressure 

 over large areas, and indirectly the cause of the smaller cy clones 

 and anticyclones of our weather-maps. I have just read my 

 statements over, and do not see how I could have made them any 

 clearer, though Professor Ferrel apparently failed to understand 

 them, and quotes for my benefit the fable of a tortoise standing 

 on nothing and supporting the world. 



Loomis believed that areas of high pressure, which he placed as 

 the antecedent phenomena in the development of cyclones, were 

 mainly the result of low temperature. Hann finds in the tem- 

 perature gradient between equator and pole the force which 

 originates and maintains cyclones. 



As I understand it, then, the point at issue is as follows : Fer- 

 rel maintaine that the essential condition for the development and 

 continuance of a cyclone is a higher temperature within the field 

 of the cyclone than in the surrounding air. Loomis and Hann, 

 whde not denying that cyclones may thus originate, conclude, as 

 a result of the study of observational data, that cyclones also 

 exist as secondary whirls resulting from atmospheric motions 

 originating outside the area of the cyclone. The cyclones thus 

 originated probably bear some analogy to the small whirls often, 

 seen in the current of a river. 



I have little doubt that Ferrel's explanation of the general cir- 

 culation of the winds is the correct one, and it is possible that the 

 views of cyclone generation advanced by Loomis and Hann will 

 need modification ; but I believe that the observational data are 

 sufficient to warrant the conclusion that the condensation theory 

 needs modification. 



Professor Ferrel appears to think that it is scarcely justifiable 

 to advance a new hypothesis until it is certain that the older theory 

 is inadequate. I cannot think, however, that this is the method 

 by which science has been advanced. There was a time when 

 the wave theory of light was less probable than the emission the- 

 ory elaborated by the mathematical genius of Newton; and, if 

 the less probable theory had not been thought over and discussed, 

 the present position of optics could never have been reached. 

 There was a time when the fluid theory of electricity was much 

 more probable than any other; and, had not invesfcigatoi-s sought 

 other hypotheses which would explain the phenomena equally as 

 well, or better, progress would have been greatly retarded. 



Many other examples might be given, but these %vill suffice to 

 show why I prefer the method of multiple hypothesis advocated 

 by President Chamberlin to the method of not considering but 

 one hypothesis or theory until it is absolutely certain that it is 

 wrong. 



If we only had some method of determining the air temperature 

 at each successive height, it would be possible to calculate in any 

 area of high pressure exactly how much of the high pressure was 

 due to temperature, and how much was due to dynamic or other 

 causes. There are certain limiting values, however, which obser- 

 vation and well-known physical laws render it safe to assume the 

 mean temperature of any air-column will not depart greatly from: 

 1st, It is improbable that the decrease of temperature with height 

 can ever be much or any greater than the adiabatic rate when 

 the air above would be potentially heavier than the air below; ad. 

 It is improbable that the mean temperature of the air-column up 



