,038 



SCIENTIFIC RECORD FOR 1883. 



mum of positive temperature departures ; southeast of a high barome- 

 ter is a local maximum of negative temperature — isabnormals. This 

 relation corresponds closely to a similar relation shown by the daily 

 simultaneous weather chart. Following this generalization, Wild ex- 

 tends his isobars into regions where but few barometeric observations 

 are available. By reading off the barometric pressure at every five 

 degrees of latitude and longitude, he compiles a table showing the 

 mean pressure of the northern hemisphere, which we have directly 

 compared with the one given by Ferrel in 1877, in Meteorological Be- 

 searches, Part I, p. 37, as follows: 



Mean barometric jircssnre reduced to standard gravity. 



(Z. O. G. M., xvn, p. 328.) 



F. Singg, as the result of some studies on the influence of the Alps 

 on the phenomena that occur during an area of high barometric press- 

 ure, arrives at the following conclusions: 



1. The surfaces of equal atmospheric pressure will be raised in pro- 

 portion to the horizontal extent of the mountainous region and the 

 height of the mountains. This effect of the mountains extends upward 

 to a neutral surface. 



2. The atmosphere sinking down upon the mountains comes under a 

 given pressure, and by compression experiences a higher temperature/ 

 sooner than at the same level over a country destitute of mountains. 



3. The inclination of the surfaces of equal pressure is therefore from 

 the center of the mountains outward in all directions; wherefore the 

 descending atmosphere acquires an outward flow with increasing 

 velocity. 



4. This latter movement hinders the cooling influence of the snow- 

 covered surface of the mountains upon the air that is flowing into the 

 valleys around, so that it brings to these a temperature more nearly 

 corresponding to that due to the compression of the air. 



