288 



METEOROLOGY IN RUSSIA. 



uiDter iDODtbs of 1870-'71, as giveu iu the following table, iu which N. 

 C. indicates the number of winds observed : 



The temperatures of the months were : iu December, — 12.2 ; Jan- 

 uary, — 4.2; February, 4.0. February is much warmer thau Decem- 

 ber, yet the temperature of the prevailing southwest winds is nearly the 

 same, differing only 1.4, while the mean temperature differs by 10o.2. 

 But we see that iu December calms were much more prevalent than in 

 February, and the temperature of the calm days very low. To show 

 more clearly that the movement of the air in this region tends to elevate 

 the temperature, I have calculated separately the temperature of light, 

 moderate, and strong southwest winds. 



Mouth. 



December . . , 



Jauuary 



February . . 



S.W. 



Liiiht. 



—3.1 



—2.0 



2.1 



Moderate. 



-2.4 



1.2 



-2.4 



Stroui 



9.7 

 13.8 

 14.4 



The strong winds are by far the warmest, the difference of tempera- 

 ture between light and strong being 12. 8 iu December, 15. 8 in Janu- 

 ary, and 12. 3 in February. The region of calms, or of the Siberian pole, 

 is bounded on the south and east by that of the Asiatic monsoons, or 

 j)eriodic winds, blowing from the land in winter and fjom the sea iu 

 summer. It is only within the last year that the true extent of this 

 interesting region has become known. In the winter the interior of the 

 continent is cooled by radiation, the atmospheric pressure rises, and tlie 

 air flows out to the Indian and Pacific Oceans, where the pressure is 

 less. In summer the continent is heated, the pressure is much lowered, 

 and the air from the surrounding seas flows in upon Asia. Encounter- 

 ing high mountains on the south and east, the sea-air is forced up into 

 a higher and colder altitude, and loses its vapor in copious rains; so 

 the gap can never be filled, as the precipitation causes a low pressure 

 near the mountain sides. These movements of air are especially marked 

 in Southern and Eastern Asia, because the heated ijlateaus of the iute- 



