6ao 



ZONES AND REGIONS [Pt. Ill, Sect. II 



' Sharp contrasts of temperature and extreme dryness characterize the 

 local climate. Thus at 42 N. in South- Eastern Mongolia, at the end of 

 November (1871), we noted a temperature of —32-7°. These severe night 

 frosts lasted throughout winter and were prolonged into the spring. On 

 the other hand, during summer, in the same locality, we experienced an 

 almost tropical heat, which is so much the more perceptible owing to 

 the absence of forests and to the great atmospheric dryness. The tem- 

 perature of the desert soil during summer rises to as much as 50 to 6o°, 

 while in winter it sinks to — 26-5° and even lower. The transitions between 

 cold and heat both in spring and autumn are very sudden.' 



The following tabular statements, which relate to a western (Nukus on 

 Amu-Daria) and an eastern point (Urga) in the desert, when compared 

 with tables relating to the North African and South-West Asiatic deserts l , 

 show most clearly the climatic difference between the northern and 

 southern deserts : — 



Desert Climate. 



WEST AND CENTRAL ASIA. 



NUKUS ON THE AMU-DARIA. 



42° 27' N., 59 yj' E., 66 meters above sea-level. 



(From Zeitschr. d. osterr. Gesellsch. f. Meteorol., 1877, p. 219.) 



1 See pp. 606-608. 



