262 Professor Agassiz on the Glacier Theory . 



I had observed, that whenever the cold of the night was not 

 very great, water was infiltrated into the bores ; and on seve- 

 ral occasions I found in the morning my thermometrographs 

 submerged, although I had taken care to empty the bore comr 

 pletely the preceding evening, and although the introduction 

 of water from above was prevented by little drains, and by the 

 manner in which the aperture was closed. I saw at once the 

 importance of this fact for the theory of dilatation, and I pro- 

 ceeded carefully to examine this accumulation of water. The 

 following is the method I adopted. After having thoroughly 

 emptied the bores, I measured from time to time the quantity 

 of water that had been accumulated, by plunging into the hole 

 a sounding line, which I kept stretched in such a manner as 

 to rub against the sides of the hole as little as possible. The 

 length which I found to be moist when I withdjjew it, gave me 

 the depth of the accumulated water. The following observa- 

 tions were made simultaneously in two bores, of which the 

 one had a depth of 30 feet, and the other of from 120 to 140 feet. 

 The first of these holes, of equal diameter throughout, had been 

 bored with a fleuret of 3^ inches in diameter ; the large hole, 

 on the contrai'y, went on decreasing in diameter from above 

 downwards, having been bored to a depth of 92 feet with a 

 fleuret 6 inches in diameter, from 92 to 110 feet with 2^ fleuret 

 of 5 inches, and beyond 110 feet with a^e?^re/ of 3^^ inches. 



Quantities of water accumulated in the small and large bores. 



j SMALL BOBE 



at a depth of 

 I 30 feet. 



i 



ft. in, 

 Niglit of Aug. 31 1 



—Sept. 1 1 6 



Dayof Sept. 1 ...I 9 10 



Night of 1st— 2d 16* 



Dayof2d ' 2 6 



Nightof 2d— 3d..i 6 



Day of 3d , 2 8 



Night of 3d— 4th' 3 



Day of 4th 3 4 



Nightof4th— 5th 1 8 



LARGE BOBE 



at first at 120 

 feet, and af- 

 terwards at 

 increasing 

 depths to 140 

 feet. 



ft. in. 



6 



29 6 



12 



10 



3 6 



20 



3 

 18 



4 



Temperature of the air. 



Minimum. 



Maximum. 



+ 0°.3(32°.54F.)| 

 + 0°."7(33°.26*F.)| 



+ 6°.7(:V3°.26*F.)| 

 + r.O (33°.8 F.) 

 -4°.0( + 24°!8F.) 



+ 8°.7(47°.66F.) 

 + 2X5(30 F.) 

 + 3°.6,(37'.4F.) 

 + 3^6(38°.48F.) 



* During this night the small bore remained open, and some water was 

 introduced from the surface, Avhoreas the large bore was clo.sed. 



