the Hintereis Glacier. 161 



prevent the ice from sliding sideways before it had become 

 embedded in the stone, and upon the ice rested a piece of 

 wood upon which a weight of 11*3 kg. was slung. To 

 prevent this piece of wood from sliding on the ice, a glass 

 rod was half embedded in the wood and half in the ice. 

 From this piece of wood ran a rod connecting it with the 

 recording lever. Another sling, secured to a piece of wood, 

 served to carry a load whereby pressure was brought to 

 bear upon the ice sample for the purpose of causing it 

 to " slip" over the stone below in a direction parallel with 

 the grooves in the stone. 



The whole was surrounded with blocks of ice as before, 

 and a thermometer-bulb lay in the ice-cavity containing 

 the ice sample to be tested. 



To get the temperature below the freezing-point, a dish of 

 ice and salt was place i upon the ice surrounding the bar, and 

 two other small cans with salt and ice were placed at the sides. 



In about four hours' time the temperature had fallen 

 to — o, 3 C. In another hour and twenty minutes the 

 temperature was — o, 8 0. The load used to cause the ice 

 to slide on the rock was in position, but no movement took 

 place at these temperatures and the ice was ,rmly frozen to 

 the rock. During the next three hours the ice did not 

 move, and the temperature slowly fell to o, C. 



The insulation of the box v\as then improved by covering 

 it up with flannel, the load tending to cause the ice to slip 

 removed, and the whole allowed to rest for nine hours. 

 At the end of this interval the temperature was still 0°'0 C, 

 and the recording finger showed that no appreciable slip had 

 occurred. 



The load to produce slip was then put on, and the readings 

 shown on diagram fig. 7 obtained. It will be noticed that 

 some time after each slight rise of temperature the velocity 

 of slip very slightly increased, and that when the temperature 

 fell the velocity of slip decreased. 

 Data : — 



Hours in a year = 8760. 



Mean slip during seven hours = 0*017 cm. per hour. 



Shear force during test = 0*907 kg. 



Area of ice sample = 13*4 cm. 2 . 



Shear force at centre of glacier = 0'822 kg. per cm. 2 . 

 This is the mean over about three-fourths of the central 

 portion of the glacier. 



Sli ;> = 876 ° xQ'Ql^x 131 x -822 

 1P 0-907 



= 18'08 metres per annum. 

 Phil. Mag. S. 6. Vol. 27. No. 157. Jan. 1914. M 



