NOTES. XV 



217 such feet to one such degree. We are, therefore, induced to consider that 

 the results of the observations hitherto obtained in the Schergin boring, or shaft, 

 are by no means sufficient to determine, with certainty, the measure of the in- 

 crease of temperature; but yet, that (notwithstanding great deviations which 

 may be occasioned by differences in the heat-conducting power of the strata, 

 and in the disturbing influence of water or air which may sink down from the 

 surface) we may venture to say that, on the whole, the temperature increases 

 1 Reaum. for a descent of not more than 100 to 117 Eng. feet." The result 

 of 117 Eng. feet, is the mean of six partial results, or augmentations of tem- 

 perature from at every 50 feet between 100 and 382 feet depth in the shaft. If 

 I compare the mean atmospheric temperature of the year at lakutsk ( 8 0< 13 

 Reaum.) with the mean temperature given by observation of the ice at the 

 lowest part of the shaft ( 2'40 Reaum. greatest depth 382 Eng. feet), 

 I find 66| Eng. feet for 1 Reaum. The comparison of the deepest part with 

 the temperature 100 feet below the surface, gives 100 feet. From the saga- 

 cious numerical investigations of Middendorff and Peters on the rate of propaga- 

 tion of variations of atmospheric temperature, and on the maxima and minima 

 of temperature (Middend. S. 133 157 and 168 175), it follows, that in the 

 different borings, at the small depths of 7 to 20 or 21 feet in the upper portions 

 of the borings, there is " an increase of temperature from March to October, and 

 a decrease from November to April, because spring and autumn are the seasons 

 at which the changes of atmospheric temperature are most considerable." (S. 142 

 and 145.) Even carefully covered-over mines in Northern Siberia cool gradu- 

 ally in the course of years, from the contact of the air with the sides of the 

 shafts. In the Schergin shaft, however, in the course of eighteen years, this 

 contact has occasioned scarcely half a degree Cent. (0'9 Faht.) diminution of 

 temperature. A remarkable, and, as yet, unexplained phenomenon, which has 

 also presented itself in the Schergin shaft, is an increase of temperature which 

 has sometimes been perceived in winter, exclusively in the lower strata, and 

 "without any demonstrable external influence." (S. 156 and 178.) A more ex- 

 traordinary circumstance, as it appears to me, is that in the boring at Wedensk, 

 on the Pa'sina, with an atmospheric temperature of 28 Reaum., 2'5 was 

 found at the very small depth of between 5 and 8i feet ! The isogeothermal 

 lines, to the direction of which Kupffer's sagacious investigations first called at- 

 tention (Kosmos, Bd. i. S. 445 ; English edition, Note 201), will probably long pre- 

 sent many unresolved problems. The solution is particularly difficult where 

 the complete piercing through the stratum of ground ice is a work of much 

 time. The ground ice at lakutsk can no longer be looked upon as a mere local 

 phenomenon, as in the view of those who attributed it to a sinking of the 



