THERMODYNAMICS OF ATMOSPHERE VON BEZOLD 271 



to east, whereas it is a well-known fact that under the influence of 

 the general circulation of the atmosphere 24 the opposite direction of 

 motion can sometimes occur. 



The thunderstorms that come from the east are, however, always 

 relatively infrequent and moreover in comparison with those from 

 the west are feebly developed and have a smaller progressive veloc- 

 ity. 25 



I find the reason for this in the consideration that without the 

 cooperation of the general circulation of the air the direction of 

 propagation must always be from west to east, and that therefore 

 in those cases where the region in question lies under the influence of 

 a barometric depression located to the southward so that the general 

 atmospheric movement is from east to west, there are two opposing 

 factors that disturb the vigorous and typical development of the 

 phenomenon. 



Finally, I may add that it seems to me appropriate to designate 

 as "Front ge witter" those thunderstorms that present the just 

 described band advancing perpendicularly to its length or "broad- 

 side on," whereas the individual scattered thunderstorms, such as 

 frequently occur under otherwise similar conditions I call "Erratic 

 thunderstorms," just as was done by Fron. 



The fact that in individual years, and often in a series of consecu- 

 tive years, "Front" thunderstorms occur, whereas in other years 

 only "Erratic" storms occur, seems to me to be a question that is in 

 the highest degree worthy of a thorough study and one to which 

 I would therefore call especial attention. 



Moreover, it is very clear that the occurrence of Front storms 

 must depend largely on the configuration of the country and on the 

 features of the soil. 



Therefore in accord with this idea such storms attain to a greater 

 development in the interior of France and Germany than in the 

 Scandinavian Peninsula or in Italy, where the plains of Sweden and 

 the Po satisfy the required conditions to a high degree. 



It is also apparent that the sloping surfaces of meridional moun- 

 tain ranges, as in the Vosges, the Black Forest, and the Bohemian 

 Forest, must especially favor the formation of Front storms. 



After these general remarks on the theory of the formation of 



24 Compare von Bezold and Lang (Beob. etc.): Observations at the 

 meteorological stations in the Kingdom of Bavaria. Annual volume for 1880, 

 pp. xviii-xx. 



25 C. Lang, in Lang and Erk: Observations at the meteorological stations 

 in the Kingdom of Bavaria. Annual volume for 1888, pp. xxxvii-xlix. 



