THE TEMPE^iJLt'eARTH. 45 



Schergin's shaft than has been obtained from different bor- 

 ings in Central Europe, whose results approximate closely to 

 one another (see p. 37). The difference fluctuates between 

 i-th and -|th. The mean annual temperature of Jakutsk was 

 determined at 13.7 F. The oscillation between the summer 

 and winter temperature is so great, according to Newerow's 

 observations, which were continued for fifteen years (from 

 1829 to 1844), that sometimes for fourteen days consecutively 

 in July and August, the atmospheric temperature rises as 

 high as 77, or even 84.6 F., while during 120 consecutive 

 winter days from November to February, the cold falls to 

 between 42. 3 F. and 69 F. In estimating the increase 

 of temperature which was found on boring through the 

 frozen soil, we must take into account the depth below the 



annual temperature of Jakutsk 13.71 F. with that which was found 

 from observation to be the mean temperature of the ice (26.6) at the 

 greatest depth of the mine (382 feet), I find 29.6 feet for every increase 

 of 1 F. A comparison of the temperature at the deepest part with 

 that at a depth of 100 feet would give 44.4 feet for this increase. From 

 the acute investigations of Middendorff and Peters in reference to the 

 velocity of transmission of changes of atmospheric temperature, in- 

 cluding the maxima of cold and heat (Middend. s. 133157, 163175), 

 it follows that in the different borings which do not exceed the in- 

 considerable depth of from 8 to 20 feet, " the temperature rises from 

 March to October, and falls from November to April, because the 

 spring and autumn are the seasons of the year in which the changes of 

 atmospheric temperature are most considerable" (s. 142 145). Even 

 carefully covered mines in Northern Siberia become gradually cooled, 

 in consequence of the walls of the shafts having been for years in con- 

 tact with the air; this cause, however, has only made the temperature 

 fall about 1 F. in Schergin's shaft, in the course of eighteen years. 

 A remarkable and hitherto unexplained phenomenon, which has also 

 presented itself in the Schergin shaft, is the warmth occasionally ob- 

 served in the winter, although only at the lowest strata, without any 

 appreciable influence from without (s. 156 178). It seems still more 

 striking to me, that in the borings at Wedeusk, on the Pasina, when 

 the atmospheric temperature is 31 F. it should be 26. -4 at the 

 inconsiderable depth of 5 or 10 feet ! The isogeothermal lines, whose 

 direction was first pointed out by Kupffer, in his admirable in- 

 vestigations (Cosmos, vol. i, p. 216) will long continue to present prob- 

 lems that we are unable to solve. The solution of these problems is 

 more e-pecially difficult in those cases in which the complete perfora- 

 tion of the frozen soil is a work of considerable time; we can, however, 

 no longer regard the frozen soil at Jakutsk as a merely local pheno- 

 menon, which, in accordance with Slobin's view, is produced by the 

 terrestrial strata deposited from water (Middend. s. 167). 



