and the Cnjstallization of Ice. 409 



narrow clefts were filled from above with ice, which now looked 

 like shining veins in a black rock*. 



{Reise urn die Erde, u. s. w., Histor. Abth. vol. i. p. 648. 

 Travels in Siberia, &c. vol. ii. p. 25.) 



December 9, at Obdorsk ; lat. 66° 31', long. 64° 32' east from 

 Paris. — Hills separated by narrow glens form the right bank of 



the river Polni Here it was not the action of water which 



gave these hills their remarkable outlines, but the frost, which, 

 causing cracks in the earth of great depth, frequently separates 

 masses which resemble basaltic columns of colossal size. The 

 water which runs down to the river along these tracks, on the 

 melting of the snow, wears away only the outer edges, for at a 

 little depth the ground here remains perpetually frozen. 



{Reise urn die Erde, u. s. w., Histor. Abth. vol. i. p. 690. 

 Travels in Siberia, &c. vol. ii. p. 65.) 



December 12, near Obdorsk With a perfectly clear 



sky, and the thermometer at — 27°-5 R., we set oflp at ll^^ 18"" 

 A.M., just as the sun was rising from the houses on the ridge 

 into the valley. At first we travelled on the ice of the Polni, 

 between hills deeply cracked with frost. 



(Reise um die Erde, u. s. w., Histor. Abth. vol. ii. p. 159. 

 Travels in Siberia, &c. vol. ii. p. 265.) 



February 22, on a Transbaikalian steppe In many places 



the ground was cracked by the frost, and the deep clefts crossed 

 one another in many diflFerent directions. I had seen cracks of 

 the same kind in the snowless valley between Troitsko Savsk and 

 Kiakhta, and also at Obdorsk on the driest parts of the elevated 

 banks of the Obi. 



* As for the frost alluded to in this passage, see Travels in Siberia, 

 vol. ii. p. 368 (Reise um die Erde, Histor. Abth. vol. ii. p. 252) : — 



I found the constant temperature of the ground and the mean 



temperature of the air to be both nearly — 6° R A degree of cold 



exceeding —40° R. takes place in Yakutsk every year between the 17th 

 of December and the 18th of February, and most frequently in the first 



three weeks of January In the present year (1829) the cold was 



somewhat severer ; on the 25th of January it reached its maximum with 



—46^4 R In ordinary years the mean temperature of two months is 



under — .'J2° R., so that mercury is in this place a solid body for one-sixth 

 of the year. 



