Scientific Intelligence, — Geohgy. 205 



servations made on the temperature of the air in the same town 

 during many consecutive years, with thermometers which I 

 have carefully compared with ray own. Some results are sub- 

 joined : 



You will conclude from these observations, as I have in the 

 accompanying volume, that the mean temperature at Jakoukz is 

 'perfectly in accordance with the temperature of the upper strata^ 

 which I have observed, by taking my thermometer to a depth of 

 50 Jeet (English) below the surface. This being the case, it 

 necessarily follows, that, in boring deeper, unfrozen strata will 

 not be reached till the increase of heat resulting from the ap- 

 proach to the centre of the globe shall amount to 6° R., equal 

 to 454° Fahr. The experiments which have hitherto been 

 made in the pits of Europe, and those which I have made in 

 the Oural mines, carry this increase to 1°R. = ^°.25 F. for 

 every 90 or 100 French = 96 or 106 English feet. Hence, I 

 do not expect the unfreezing at Jakouzk at a less depth than 

 500 or 600 French feet = 533 or 639 English feet. The ob- 

 servations which M. Schergin has made since my departure from 

 Jakouzk, and during which they have descended to a depth of 

 400 English feet, perfectly confirm what I have advanced con- 

 cerning the mean temperature of the air and soil of this lo- 

 cality ; for they have since found at 



Ihe depth of 77 feet English, a temperature of + 19.63 Fahr. 



119 -1-23.00 



382 +30.88 



They also indicate, for the strata occurring in this country, 

 an increase of heat in the ratio of 1° R. = 2°.25 F. to about 



