l^S Scientific Intelligence— Meteorology, 



penetrates to tlie same depth in a similar period of time ; the 

 maximum of cold taking place at mid-summer, and of heat at mid- 

 winter. 



But he also expressed his conviction that these alternate waves were 

 not sufficient to account for the phenomena, further remarking, that 

 were they the only powers employed, the paradoxical phenomena 

 should occur equally in some of the other caverns of the Orenburg 

 hillock, or in other caverns in different quarters of the globe. Pie 

 observed, that there must be something peculiar to the lUetykaya 

 Zatchita cavern which renders it the only cave in the world which 

 possesses the singular property, so far as he knew. He then al- 

 luded to the caverns in different parts of the globe in which ac- 

 cumulations of snow are founl in summer, and concurred with Mr 

 Murchison in thinking that they have no analogy with that of Oren- 

 burg. They are merely receptacles of the winter snow and ice, and 

 preserve it during summer, after the manner of an ice-house. 



The circumstance peculiar to the Orenburg cave is the occur- 

 rence of the rents and fissures which rise from the back part of 

 the cavern. 



The author stated, that if it were granted that these fissures reach 

 the surface, even by the smallest ramifications, and that they ascend 

 within the reach of the alternate waves of heat and cold, the v/hole 

 phenomena may be easily and satisfactorily explained. He ascribed 

 the summer's coldness and congelation to a constant current of cold 

 air through the fissures of the rock into the cavern ; and he sup- 

 posed that the current is occasioned in the following manner : When 

 at the close of spring the temperature of the external air and of 

 that in the rents is the same, no particular occurrence takes place ; 

 but as soon as the wave of cold begins to make impression on 

 the rocky parietes of the fissures, then the air in them will be 

 somewhat cooled, contracted, and rendered specifically heavier. 

 This being so, the weiojlit of the column of air in these rents will be 

 greater than that of a column of equal altitude of the external at- 

 mospheric air, and the consequence will necessarily be, that the colder 

 air will descend, the warmer atmospheric air from above will supply 

 its place, which, in its turn, will be cooled and descend, and thus a 

 current of cold air through the crevices into and through the cavern 

 will be established. As the temperature of the rocky parietes 

 gradually falls with each successive wave of cold, the air in the 

 fissures will become colder and colder, and in the same proportion 

 will descend more rapidly. 



