September 25, 1891. J 



SCIENCE. 



177 



abundantly and most intensely, with uniform air pressure, weak 

 winds, a strong heating of the lower air strata, and a high hu- 

 midity of the air. 



"The storms of the temperate latitudes have, moreover, still 

 another peculiarity, outside of their maximum action in the cold- 

 est season during a period of the greatest stability in the thermic 

 equilibrium of the atmosphere, which stands in contradiction to 

 the convection theory, namely, a tendency to take the same path 

 one after the other. Upon this peculiarity KOppen has remarked 

 before (Met. Zeit., 1874, Vol. IX., p. 380), and we need only to 

 examine the daily weather charts to find clear examples in abun- 

 dance. 



" This view is wholly contrary to the facts which the true cy- 

 clones of the convection theory show, and must show. A cyclone 

 equalizes the temperature above and below in the region through 

 which it passes. The condensation process heats the higher layers, 

 cools off the lower, and makes a more stable equilibrium in the 

 atmosphere. At the same time the moisture of the lower air 

 layers is used up, and at the same place precipitation cannot occur 

 again through pure convection currents. The cyclones of the 

 convection theory must diminish or become extinct, if placed 

 where shortly before another cyclone was in activity which has 

 disposed of the latent energy stored up in the lower layers of 

 the atmosphere in the form of high temperature and great 

 moisture. 



" The heat thunder-storms of our summers do not show this 

 peculiarity, and are appearances to which the pure convection 

 theory can find full application. On the other hand, the fact 

 that the cyclones of our latitudes often follow a path behind each 

 other, shows that the convection theory has no application, or 

 only a subordinate one, and that the force upon which their origin 

 and advance depend most importantly is not in themselves, but 

 must be sought outside. We must refer to the conditions of the 

 general distribution of pressure and currents of the general atmos- 

 pheric circulation for their origin and development. 



"If we correlate the origin and forward movement of the cyclones 

 of the temperate and high latitudes with the general circulation 

 of the atmosphere, then the greater frequency and intensity in 

 winter explains itself wholly, as well as all the peculiarities which 

 the application of the pure convection theory contradicts. That 

 also in whirls of this origin the condensation of moisture plays a 

 greater or less secondary role no physicist can well doubt." 



This is a most significant utterance and important attack upon 

 the convection theory. Heretofore this theory has been assailed 

 in England and this country from outside, but now the attack is 

 from within the camp and by one of the foremost of its former 

 defenders. The arguments, to be sure, are rather old, but they 

 are put in a fresh dress. We welcome Dr. Hann to our side of 

 the controversy. It should be noted that, as Miss Gierke has said, 

 the original convection theory has been so added to and corrected 

 it can hardly be recognized. Dr. Hann takes up only one view, 

 and the one applicable to the summer season; but there is another 

 view which applies to the winter, namely, that an unstable equi- 

 librium in the atmosphere may occur whenever, through any 

 reason, a central core becomes heated above its surroundings. 

 This gives a less diminution of temperature with height, instead 

 of greater-, as in the other view, and at the same time causes a 

 rising tendency in the air; this has been called the "balloon" 

 effect. Dr. Hann will find that the "chimney" effect has been 

 relegated to the tornado, in which the height is very much greater 

 than the breadth. 



There would seem to be no greater difficulty in accounting for 

 the moisture and generation of a storm which follows another than 

 in accounting for these conditions in the first. It is not supposed 

 that a storm carries away very much from any region, but each 

 one may feed upon the conditions which surround it. In fact, 

 there is probably a good deal more tnoisture in sight and usable 

 after a storm has passed than before, unless the first storm is fol- 

 lowed directly by a high area, which is contrary to Dr. Hann's 

 supposition. It does not seem as though these and other more 

 serious objections to the old theory can longer be ignored by con- 

 vectionists. H. A. Hazen. 



Washington, D.C., Sept. 21, 



BOOK-REVIEWS. 

 A Girl in the Karpathians. By Menie Muriel Dowie. New 

 York, Cassell. 8°. $1.50. 



That this is an entertainingly written book of travel few will 

 deny. The region described is one visited little, or we might say 

 not at all, by the ordinary tourist, and the author abandoned her- 

 self to a life with the natives for the several months she was in 

 the Karpathians. 



That there are many girls like Menie Muriel Dowie may well 

 jbe doubted, and perhaps it is as well that there are not. She is 

 certainly bright, but independent almost to a fault. In answer tO' 

 those asking why she went alone, she writes: "I gaze at their 

 indulgent, smiling eyes, and their self-satisfied faces, and I dare 

 not tell them that I do it from sheer bold preference. I couldn't 

 have the heart to wound and shock them so, and I say, what is 

 perhaps also true, that I am driven to it, for nobody cares to come 

 to the places I care to go to." That there must be a little of self- 

 satisfaction in Miss Dowie's face, one cannot help thinking. There 

 must be some self-reliance at least in a girl of twenty-five, as the 

 author describes herself, who, armed with a revolver and dressed 

 in knickerbockers, plunges into a thinly-settled region for a so- 

 journ of months. She hails from Scotland, but a love for cigar- 

 ettes does not at all conform with the general conception of a 

 Scottish lassie's character. 



But eccentricities can be overlooked in one as clever as Menie 

 Muriel Dowie, and the interest in her personality adds to the charm 

 of her book. She shows her youth occasionally in the earnestness 

 of her self-communing over the problems of life, but her account 

 of the people she lived with is well worth reading. To be sure 

 she tells us inadvertently that it is the way of returning travellers 

 to swap lies, but the book shows little sign of its being a work of 

 fiction. 



AMONG THE PUBLISHERS. 

 The next volume of the Contemporary Science Series, pub- 

 lished by Chas. Scribner's Sons, will be " The Man of Genius," by 

 Professor Lombroso. This volume, which will be issued on Sep- 

 tember 25, will be copiously illustrated. 



— Messrs. Smith, Elder, & Co. have in preparation "Vertebrate 

 Embryology," by A. Milnes Marshall, F.R.S., professor in the 

 Victoria University, Beyer professor of Zoology in Owens College, 

 late fellow of St. John's College, Cambridge; new, revised, and 

 cheaper edition of Finlayson's " Clinical Manual; " new edition of 

 Farquharson's "Guide to Therapeutics;" new edition of Parti, 

 of MacCormac's " Surgical Operations." 



— This year's volume of the Annual of the Office of Naval In- 

 telligence, just issued from the government printing office at 

 Washington, is the tenth in the series of general information from 

 abroad, and retains the title of last year's number, " The Year's 

 Naval Progress." It has a chapter on ships and torpedo-boats, 

 one on machinery, and one each on ordnance, electricity on ship- 

 board, and the naval manoeuvres of 1890. Chapter VI. treats of 

 the armor question in its present aspect, as viewed in the light 

 of recent practical tests ; and Chapter VII. presents a view of the 

 different systems of coast defence of the various European States. 

 Other chapters are devoted to high explosives, torpedo vessels, and 

 promotion in Em'opean navies; and the final chapter gives a list 

 of books on professional subjects. 



— Messrs. Sampson Low, Marston, & Co announce: "Theory 

 and Analysis of Ornament," applied to the work of elementary 

 and technical schools, by Francois Louis Schauermann, for eight 

 years head mastei' of the wood and carving department. Royal 

 Polytechnic, Regent Street, with 263 illustrations; "Answers to 

 the Questions on Elementary Chemistry," theoretical and practical 

 (ordinary course), set at the examinations of the science and art 

 department. South Kensington, 1887-91, by John Mills, formerly 

 of the Royal College of Science, London, author of " Alternative 

 Elementary Chemistry," fully illustrated; "Chemistry for Stu- 

 dents," consisting of a series of lessons based on the syllabus of the 

 science and art department, and especially designed to facilitate 

 the experimental teaching of elementary chemistry in schools and 

 evening clashes, by John Mills, author of " Alternative Elementary 



