396 



SHORT MEMOIRS ON METEOROLOGICAL SUBJECTS. 



imum rainfall, and the wind-roses of Zechen and Vienna show that in 

 fact it caonot be dependent upon the latter. The distribution of pres- 

 sure in the wind-roses shows no dependence upon the distribution of 

 rainfall, and this is further testimony that the rain cannot be the cause 

 of the low pressure during S. and SW. winds. If we unite into one 

 mean the corresponding values for the places having similar distribution 

 of rain, we obtain the following more general series of figures: 



Breslau.Zeclien.Gor- C Eain . . 



liiz, and Vienna. ( Barom 

 Berlin, Elsflelb, and J Rain . . 



Utrecht. i Barom 



If we start with the lowest barometric reading, and form the changes 

 of pressure by passing from one wind-direction to the next, we obtain 

 the following series of numbers : 



Therefore, in spite of the increasing rainfall, as the wind veers from 

 SW. to N W. the pressure increases by 3.4 millimeters in series A. If the 

 rain caused the slightest sensible fall in pressure, then in the wind-roses 

 for Vienna, Breslau, &c., the minimum of pressure would change from 

 the south to the west side. But notwithstanding that only little rain 

 falls with S. and SW. winds in Vienna, Breslau, &c., still the atmos- 

 pheric pressure is lowest with these winds, precisely as at those places 

 for which the maximum rainfall and the minimum pressure nearly 

 coincide. 



Since on the north slope of the Alps* and on the northeast side of the 

 Eieseugebirge, the heaviest precipitations occur on the southwest side 

 of the storm center, therefore the latter should receive a tendency to 

 remain stationary or even to retrogress. This deserves a further exam- 

 ination. 



* Especially in the valley of Vienna. In Munich and Kremsmiinster, the maximum 

 rainfall appears to occur with west winds ; but Vienna is also protected on the west 

 by spurs of the Alps. 



