RECENT SCIENCE. 397 



exciting just now a great deal of interest, has openly broken with 

 the old theory as regards the origin of cyclones and anticyclones.* 

 From observations made for several years in succession on the 

 top of the Sonnblick a peak twelve thousand feet high, of the 

 Tyrolese Alps as well as from observations made on several 

 high-level stations, he has concluded that a cyclone can not be due 

 to a local heating of the earth's surface and to an ascending cur- 

 rent of warm air provoked by this cause, just as an anticyclone 

 can not be due to a local cooling of the earth's surface, and to a 

 consequent condensation of the air. Contrary to the previsions 

 of the meteorologists, the ascending column of air within a cy- 

 clone, up to a height of some ten thousand feet, is not warmer 

 than the surrounding air ; it is cooler within the cyclone, and its 

 upward motion thus can not be due to its temperature. So also in 

 an anticyclone the descending current of air is warmer than it is 

 under normal conditions, and its downward motion must be due 

 to some other cause than an increase of density resulting from a 

 lowering of its temperature. The decrease of pressure in the one 

 case, and its increase in the other, thus can not be caused by dif- 

 ferences of heating or cooling of the lower strata ; and both cy- 

 clones and anticyclones must be considered as parts of the general 

 circulation of the atmosphere, such as it was conceived by Ferrel.f 



Such a deep modification of the current views, though sup- 

 ported to a great extent by weighty evidence, will obviously not 

 be accepted without opposition; but it is already making its way, 

 and certainly will exercise a deep influence on the further devel- 

 opment of meteorology. 



Abandoning now the domain of theoretical investigation, I 

 must mention a work also a life's work which may safely be 

 placed side by side with the best achievements in theory. I mean 

 the beautiful charts of Mr. Buchan, representing the distribution 

 of pressure, temperature, and winds over the surface of the globe, 

 embodied in the last volume of the Challenger Expedition Re- 

 ports. When Mr. Buchan published twenty-three years ago his 

 first maps of monthly isobars and prevailing winds, they were 

 quite a revelation, even though the data upon which they were 

 based were very incomplete at that time.J: But better data have 



* Das Luftdruckmaximum vom November 1889, in Denkschrift der Wiener Akademie 

 der Wissenschaften, 1890, Bd. Ivii, p. 401. Bemerkungen iiber die Temperatur der Cyclonen 

 und Anticyclonen, in Meteorologische Zeitschrift, 1890, p. 328. 



f See the discussion of this subject between Hazen and J. Hann in Science, 1890, xv, 

 382-384, and Meteorologische Zeitschrift, 1890, p. 328. 



\ To trace the isobars, or lines of equal atmospheric pressure, reduced to the sea-level, 

 the real altitude of each meteorological observatory must be known from direct geometrical 

 levelings; but in 1869 the altitude of not one single station in Siberia, .central Asia, or 

 even the Urals was known. A leveling across Siberia, as far as Lake Baikal, has been 



