378 Prof. BischofF o« the Temperature of 



reached the depth of 90 feet, finding the earth still frozen, they 



refused to fulfil their engagement.* 



Some philosophers have considered this contradictory to the 

 supposition that the interior of the earth is in the state of fusion. 

 But from the following account it will be seen that, in those 

 frozen str- *a, the general phenomenon of an increase of temper- 

 ature with tii" depth is not wanting, and that by continuing the 

 work, they have arrived at a temperature which leaves no doubt 

 that they are not far from the lower limits of the frozen soil, 

 and that water, the object of their undertaking, is not far dis- 

 tant. 



It is well known, says an article from St Petersburg, in the 

 Berlin news of the 24th February 1832, that at Jakutzk in Si- 

 beria, the earth, even in the hottest summer, only thaws to about 

 the depth of three feet. Hitherto all attempts to discover the 

 thickness of the frozen strata beneath, have been fruitless. Since 

 the year 1830, one of the inhabitants of Jakutzk has been en- 

 gaged in sinking a well, by which means it may, perhaps, be 

 ascertained. In the same year the workmen reached the depth 

 of seventy -eight feet below the surface, but still found no water. 

 In the year 1831, they reached ninety feet, and were still in the 

 frozen soil. The work is still in progress, and there seems no 

 doubt of their attaining their object, for the thermometer, which 

 shewed 18°.5, a few feet below the surface, rises, when sunk to 

 the bottom of the well, to 29°.15.f 



It is evident that in high latitudes, where the mean tempera- 

 ture of the soil is below 32°, there must exist a frozen stratum 

 of earth of a certain thickness, which can only thaw during the 

 summer, to that depth beyond which the influence of the exter- 

 nal temperature is no longer felt. For, in the same manner as 

 in our climates, the soil is frozen to a certain depth by the cold 

 of winter, so must the frozen soil, in those high latitudes, be 

 thawed to a certain depth by the heat of summer, In Siberia, the 

 temperature of the soil is near 32°, in the latitudes of the North 

 of' England and Scotland; for Von Humboldt and Adolphus Er- 



• Against this, see V. Biich in Poggendorff's Annal, vol. xii. p. 405. 

 •\ See Erman, in Poggendorff's Annal., vol. xvii. p. 340, Von Humboldt, 

 ibid. vol. xxiii. p. 104 and 106, and Hansteen, ibid. vol. xxviii, p. 584. 



