METEOROLOGY IN RUSSIA. 293 



summer rains, but in the prairie States tlie maximum of falling: water is 

 reached earlier; so in Missouri and Kansas there is a marked maximum 

 in June ; farther to the south even in April and Mixy, which is due to 

 the earlier vegetation. lu the wooded Atlantic sea-board, on the con- 

 trary, there is uo such tendency to an early maximum, the rains being 

 very equally distributed in the Northern States, and having a maximum 

 in July or August in the South. 



Besides the above stated difference between the north and south, 

 there is a marked one between the east and west of Russia. Precipi- 

 tation in winter is much less in the former. This is not due to the differ- 

 ence of the currents of the air, but to the winter cold, which is greater 

 in the east. The warm, moist southwest winds contain little vapor in 

 Eastern Eussia, and therefore the quantity precipitated cannot be great. 

 Yet snow falls occasionally, and in small quantities, even at Jakutsk, 

 which has the coldest winter of which we have any knowledge. Snow- 

 falls have been observed there at temperatures of from — 40 to — 4G Fahr. 

 The rain-fall of summer does not diminish generally from the Baltic to 

 the Obi in Siberia. Local circumstances seem to have a great inflneuce 

 on the summer rains, but their study requires many more observations. 

 There are also two small regions with prevailing rains in autumn — one 

 on the Baltic coast, comprising Southwest Finland and Libau ; another 

 in the southern part of the Crimea, south of the Jaila Mountains. 



3. Nearly rainless region of the Caspian and Kirghez steppes. Hero 

 the amount of rain falling yearly is from 4 to 6 inches, and is very irreg- 

 ularly distributed. It is an arid, desolate country, in which agriculture 

 is impossible without irrigation. The boundary of the region of sum- 

 mer rains No. 2 is very clearly marked on the west. It is the high, right 

 bank of the Volga from 50° to 48° K, and a line of heights called Jergeui, 

 forming its continuation to the south, extending to the Kuma-Mauytsch 

 depression, about 40° N. On the south of this depression the plateau 

 of the Western Caucasus rises, and its eastern border is also the line 

 of division between the two regions, the eastern being low, salt, and 

 desert; the western having regular summer rains, and a luxurious nat- 

 ural grass vegetation. A great part of it is already under cultivation, 

 yielding excellent corn-crops. 



The mountains of Central Asia have more rains than the steppes at 

 their foot, and the rivers descending from them are extensively used 

 for irrigation. The inhabitants are well aware of the benefit of this sys- 

 tem, and, though not very civilized, have excellent modes of irrigation. 

 The whole of Central Asia, as much as we know of it, has a similar cli- 

 mate, the sedentary inhabitants gathering around mountain streams, 

 and often draining them to the last drop for their fields. 



4. East of this country is the monsoon region of Eastern Asia, with au 

 enormous prevalence of summer rains. The principal features and ex- 

 tent of this region have been already described. These are the four 

 principal regions from the Baltic to the Pacific. The floods of the riv- 



