THE FROZEN SOIL. 45 



means of the admirable investigations of Erman, Dacr, and 

 MiddendorfF. In accordance with the descriptions given of 

 Greenland by Cranz, of Spitzbergen by Martens and Phipps, 

 and of the coasts of the sea of Kara by Sujew, the whole of 

 the most northern part of Siberia was described by too husty 

 a generalization as entirely devoid of vegetation, always froz- 

 en on the surface, and covered with perpetual snow, even in 

 the plains. The extreme limit of vegetation in Northern 

 Asia is not, as was long assumed, in the parallel of G7°, al- 

 though sea-winds and the neighborhood of the Bay of Obi 

 make this estimate true for Obdorsk ; for in the valley of 

 the great River Lena high trees grow as far north as the 

 latitude of 71°. Even in the desolate islands of New Si- 

 beria, large herds of rein-deer and countless lemmings find an 

 adequate nourishment.* MiddendorfF's two Siberian expe- 

 ditions, which are distinguished by a spirit of keen observa- 

 tion, adventurous daring, and the greatest perseverance in a 

 laborious undertaking, were extended, from the year 1843 to 

 1846, as far north as the Taymir land in 75° 45 / lat., and 

 southeast as far as the Upper Amoor and the Sea of Ochotsk. 

 The former of these perilous undertakings led the learned in- 

 vestigator into a hitherto unvisited region, whose exploration 

 was the more important in consequence of its being situated 

 at equal distances from the eastern and western coasts of the 

 old Continent. In addition to the distribution of organisms 

 in high northern latitudes, as depending mainly upon climat- 

 ic relations, it was directed by the St. Petersburg Academy 

 of Sciences that the accurate determination of the tempera- 

 ture of the ground and of the thickness of the subterranean 

 frozen soil should be made the principal objects of the expe- 

 dition. Observations were made in borings and mines, at a 

 depth of from 20 to 60 feet, at more than twelve points (near 

 Turuchansk, on the Jenisei, and on the Lena), at relative dis- 

 tances of from 1600 to 2000 geographical miles. 



The most important seat of these geothermic observations 

 was, however, Schergin's shaft at Jakutsk, 62° 2" N. lat.f 



* E. von Baer, in Middendorff's Rcise in Sib., bd. i., s. 7. 



f The merchant Fedor Schergin, cashier to the Russian-American 

 Trading Company, began, in the year 1828, to dig a well in the court- 

 yard of a house belonging to the company. As he had only found 

 frozen earth and no water at the depth of 90 feet, which he reached in 

 1830, he determined to give up the attempt, until Admiral Wrangel, 

 who passed through Jakutsk on his way to Sitcha, in Russian America, 

 and who saw how interesting it would be, in a scientific point of view, 

 to penetrate through this subterranean stratum of ice, induced Scher- 



