92 



SCIENCE 



[N. S. Vol. XLV. No. 1152 



mile level are thougiit to be due to as sudden a 

 change in the constitution of the air itself, to 

 especially a large loss in nitrogen and oxygen 

 and an accession of hydrogen." So far as is 

 known there is no sudden change in the air 

 composition at this or any other level.* On 

 the other hand, the author is to be credited 

 ■with keeping constantly before the reader such 

 important points as that warm air does not rise 

 of itself, but, as he states concerning thunder- 

 storm formation (p. 242) : 



It is mainly under the atmospheric movements 

 Bet up by cyclones that the bodies of cold air de- 

 scend and begin to root out the bodies of hot air 

 with the abruptness that makes thunderstorms. 



Also, the precipitation of atmospheric mois- 

 ture by cooling due to internal expansion of 

 rising air is well emphasized. On both these 

 points, Mr. Longstreth gives false impressions. 



"Eeading the "Weather," is for those who 

 want to know simply how to forecast the 

 weather either with or without instruments. 

 It is a lively account of keen personal obser- 

 vations of weather signs, set in a brief and 

 mainly accurate explanation of weather proc- 

 esses. The central theme is " sky signs for 

 campers." These the author expounds under 

 the heads clouds, temperatures, rain and snow, 

 dew and frost, thunderstorm, tornado, hurri- 

 cane, cloudburst and halo. For the particular 

 benefit of the commuter, a chapter on fore- 

 casting with a barometer follows. At the end 

 of the book is a good account of the seasons, 

 the Weather Bureau, and weather proverbs. 

 Finally, a summary of aU the prognostics pre- 

 viously described adds greatly to the value of 

 the book for reference. On account of limited 

 scope some of the physical explanations are 

 made too brief for accuracy. Thus the defini- 

 tions of anticyclone and cyclone are hardly 

 scientific : 



s See table and diagram pp. 46^7 in A. Weg- 

 ener : ' ' Thermodynamik der Atmosphiire, ' ' Leip- 

 zig, 1911. The resiilts of analyses of air samples 

 taken at 9 km. altitude, 1910 to 1912, as com- 

 pared with the earth's surface, indicate a reduc- 

 tion of about 6 per cent, in the volume of carbon 

 dioxide, and an increase of perhaps 50 per cent, 

 in the lightest gases: see Scientific American 

 Supp., December 23, 1916, p. 414. 



The anticyclone (cyclone) is an accumulation of 

 air that has become colder (warmer) than the air 

 surroimding it (pp. 20 and 44). 



The author, himself, shows the limitations 

 of these definitions when speaking of summer 

 temperatures : 



The clear skies of the preceding anticyclone had 

 permitted the laud to warm up very fast under 

 the midsummer sun, and the clouds of the cyclone, 

 by cutting off the supply, had made a relative 

 chill (p. 89)." 



Although the book was written largely on 

 the northeastern United States, its value is 

 not by any means limited to this section of 

 the country. 



DR. JULIUS VON HANN^ 



With the passing of 1915, fifty years have 

 elapsed during which Julius von Hann has 

 edited the Meteorologische Zeitschrift. Dr. 

 Hann edited the Zeitschrift der Oesterreich- 

 ischen Gesellschaft fur Meteorologie with C. 

 Jelinek from its establishment in 1866 imtil 

 1876; and, after his death, alone to the year 

 1885. On merging it with the German Me- 

 teorological Society's Meteorologischen Zeit- 

 schrift under the title of the latter, he pur- 

 sued the editorship in common with Koppen 

 from 1886 to 1891, with Hellman, 1892 to 1907 

 and since then with Siiring. 



This 50-year editorial jubilee in connection 

 with a scientific magazine is unique. Further- 

 more, never has there been an editor who even 

 made so many contributions to his scientific 

 magazine as he. ISo fewer than 134 extensive 

 articles, 1123 smaller contributions, 166 re- 

 views and numerous unsigned articles, have 

 come from him. In addition he has written 

 many monographs, and he has published what 

 are now the most exhaiastive and authoritative 

 treatises on climatology and meteorology.^" 

 Charles F. Brooks 



Yale College 



8 Taken mostly from the frontispiece by Hell- 

 mann, Koppen, and Siiring, Meteorologische Zeit- 

 schrift, January, 1916, Vol. 33. 



10 Hann 's ' ' Handbuch der EHimatologie, ' ' third 

 ed., 1908-1911, 3 vols., 8vo, 1,533 pp., 41 figs. 

 "Lehrbuch der Meteorologie," third ed., 1914r- 

 1915, with Dr. Siiring in collaboration, 4to, 847 

 pp., 28 pi., 4 tables, 108 illustrations. 



