•s 



NATURE 



[May 9, 1907 



THE LIFE-WORK OF AN EMINENT 

 METEOROLOGIST. 

 Gesammelte Abhandlutigcn aus den Gehieten der 

 Meteorologie und des Erdmagnetismus. Von 

 Wilhelm von Bezold in Gemeinschaft mit A. Coym. 

 Herausgegeben vom Verfasser. Pp. viii + 448; 

 illustrated. (Brunswick : F. Vieweg and Son, 

 1906.) Price 14 marlis. 



PROF. VON BEZOLD'S position as the late head 

 of the Prussian Meteorological Institute suffices 

 to make the publication of his collected works on 

 meteorology and terrestrial magnetism an event of 

 importance. His papers on electricity and physio- 

 logical optics remain apparently to be dealt with. 

 In preparing the present work for press, he had the 

 assistance of Dr. Coym, formerly of the Meteor- 

 ological Institute. The collection includes twenty 

 papers; in some, slight alterations ha<'e been intro- 

 duced and some notes have been added. 



Only the earliest paper, written in 1S64, represents 

 von Bezold as himself an observer. It treats of the 

 phenomena visible after sunset, especially of what 

 von Bezold terms the " Purpurlicht. " An appendix 

 refers to recent authorities, and especially to the effect 

 of volcanic ejecta on the richness of the phenomena. 



The next three papers deal with the frequency of 

 thunderstorms. It is explained in an appendix, 

 pp. 83-90, that much of von Bezold's writings on 

 this subject seemed of too local interest to reproduce. 

 In the first paper, after dealing with statistics from 

 a number of stations — mostly in central Europe — 

 von Bezold decides in favour of a connection between 

 thunderstorm and sun-spot frequency. His conclusion 

 on p. 59, repeated in the last thunderstorm paper, 

 p. 82, is that thunderstorm and auroral frequency 

 follow opposite courses, thunderstorms being least 

 frequent in j'ears of sun-spot maximum, when auroras 

 are most numerous. This conclusion must be re- 

 garded with some reserve. 



In the next paper, dealing with sun-spot data from 

 Bavaria and Wiirttemberg, von Bezold considers the 

 evidence favourable to the reality of a twenty-six-day 

 period in thunderstorms. A footnote dated 1905 

 qualifies this, pointing out that it would be natural 

 to look for the source of a twenty-six-day period in 

 the sun, and as it is probable that the seat of greatest 

 activity in the sun cfianges its position, the twenty- 

 si.x-day period will naturally change its phase, and so 

 be recognisable only in statistics covering a compara- 

 tively short period. This seems the same position as 

 has been taken up in the case of magnetic storms by 

 Maunder, who, however, finds a period of about 27! 

 days. The reality of a period the phase of which 

 alters in an indefinite way is rather a difficult matter 

 to decide. 



The third of the thunderstorm papers suggests an 

 extraordinary increase in damage by lightning in 

 Germany. In Bavaria the percentage of (insured) 

 houses struck by lightning was fully six times as 

 great in the decade 1893-1902 as in the decade 1833- 

 1842. Von Bezold appears to accept the increase as 

 proved all over Germany. Other German authori- 

 ties, it may be added, have expressed some doubts as 

 NO. 1958, VOL. 76] 



to the true significance of the insurance statistics ; 

 the phenomena may not be purely meteorological. 



Papers v.-ix., pp. 91-220, form a group devoted 

 to the thermodynamics of the atmosphere. The 

 elementary portion of air contains moisture which 

 may be wholly gaseous, or partly condensed in rain- 

 drops, in snow, or in hail. Also the air element 

 resembles a compartment of a train in that its original 

 occupants may Icavi- it at intermediate stations, whilst 

 new occupants may come in. Change of state in the 

 water contents implies evolution or absorption of heat, 

 and the five papers aim at tracing the various possible 

 modifications and identifying them with the pheno- 

 mena of cyclones, anticyclones, Fohn winds, and so 

 on. The reader to whom German presents difficulties 

 will find an English translation of the first three 

 papers of the group in Prof. Cleveland Abbe's " The 

 Mechanics of the Earth's Atmosphere"; he must, 

 however, be on his guard against misprints. The 

 present reprint contains some fresh notes, and shows 

 some alterations, e.g. on pp. 123 and 125, dealing 

 with cyclonic and anticyclonic phenomena. These 

 thermodynamical papers represent a product which 

 the typical English meteorologist will contentedly 

 deny himself. If, however, the Cambridge mathe- 

 matical meteorologist ever comes into being, he ought 

 to read these papers as part of his preliminary educa- 

 tion. If he reads them critically in the light of recent 

 meteorological knowledge he will — whether he agrees 

 wholly with the author or not — have done a good 

 deal to qualify himself for profitable research in the 

 dynamics of the atmosphere. 



Papers x.-xv. are also in the main theoretical, but 

 thev contain information from balloon ascents as to 

 temperature and moisture in cyclonic and anti- 

 cyclonic weather at different seasons of the year. 

 Paper xvi. gives statistics from various sources as to 

 the mean annual values of temperature, pressure, 

 rainfall, and cloud round parallels of the earth. To 

 obtain zones of equal area, the author takes as para- 

 meter the sine of the latitude. This paper leads 

 naturally to xvii., the first of four papers, pp. 371- 

 448, devoted to terrestrial magnetism, in which 

 von Bezold considers what he calls the " isanoma- 

 lies " of the magnetic potential, i.e. the departures 

 from the mean value round a parallel of latitude. 

 Paper xviii. deals with what the author calls the 

 normal earth's magnetism. Paper xix. treats of the 

 foundations of the Gaussian theory as based on the 

 vanishing of line integrals taken round areas on the 

 earth's surface, and discusses the diurnal variation, 

 in the light of Prof. Schuster's variation potential, 

 and its representation by vector diagrams. 



The final paper advocates the taking of magnetic 

 observations round a parallel of latitude, which 

 von Bezold suggests might pass through the south 

 of England. To a magnetician familiar with the 

 Gaussian analysis and with Schuster's work on the 

 diurnal variation, von Bezold's contributions to the 

 subject will appear to be rather a matter of defini- 

 tions and identifications than of original ideas. To 

 those, however, who have a difficulty in grasping the 

 physical significance of abstruse mathematics, they 

 may serve a useful purpose, provided it be clearly 



