Besearches on Existing Glaciers, 261 



a depth of 15 feet ; and a third in the air. I took care to 

 close the openings of the two holes, so as completely to pre- 

 vent the external air from influencing the temperature of the 

 air contained in those holes. During the four weeks that 

 these observations were continued, the temperature of the air 

 at night never descended below — 6^.5 (+ 22°.l F.) ; the mi- 

 nimum has even been + 2° (35°.6 F.) during the night, on 

 one occasion. Of course, the streamlets of water on the sur- 

 face of the glacier then continued to flow, and did so even 

 when the temperature was at + 1° (33^8 F.), or even at 

 (32° F.). In the interior of the glacier, the thermometrograph 

 sometimes indicated (32° F.), and then the bore remained 

 moist, and water was accumulated at the bottom ; some- 

 times it descended to - 0°.3 (31°.46 F.), and even to - 0^5 

 (31°.l F.) ; th^ sheath of the thermometrograph, or the cord 

 w ich held it, was, in such cases, sometimes frozen to the 

 bol tom of the bore ; and I was obliged to disengage it by 

 pouring boiling water down along the cord. On the morning 

 of the 15th of August, the thermometrograph, which had been 

 during the night at a depth of 60 feet in the glacier, was at 



(32 F.) ; the external air had been at - 3° (+ 2Q\Q F.). 

 On the 16th it was at the same, while the air had been at -f 

 1° (33°. 8 F.); on the 17th the thermometrograph indicated 

 — 0°.5 (31°.l F.), and the temperature of the air had de- 

 scended to — 2° (+ 28°.4 F.). I quote these three observa- 

 tions because they were made at the same depth, during an 

 interruption of the boring. I intend publishing afterwards all 

 the observations made at diff^erent depths. I shall merely now 

 add, that, on the night between 31st August and 1st September, 



1 placed two thermometrographs in the same hole, the one at 

 a depth of 15 feet, and the other at 125 feet, and that I found 

 both at (32° F.) in the morning. The result was the same 

 during the day of the 1st September, and during the nights of 

 the 1st and 2d and 2d and 3d September, at the depths of 15 

 and 100 feet ; while the maximum of the external air during 

 the day was 4- 8° (46°.4 F.), and the minimum of the two 

 nights was + 0°.7 (+ 33°.26 F.). During the day of the 3d 

 September, I found the temperature at (32° F.), at 15 and 

 at 125 feet in the same hole, the external air being at -i- 3" 

 (37°.4 F.). 



