AMERICAN GEOLOGIST 
AN EXPERIMENT DESIGNED TO SHOW THE UP- 
WARD MOVEMENT OF SUBGLACIAL 
DEBRIS. 
By Ossian GutuHrie, Chicago, ILI. 
The following experiment was devised sometime since by Mr. Guthrie to show that 
subglacial material rises through the ice during its forward movement. Since the experi- 
ment has been referred to in this journal* as showing that subglacial material does have 
such motion, it has been deemed advisable to give an account of the experiment an 
equally wide distribution. The experiment of Mr. Guthrie was described in a paper 
entitled “The Lake Michigan Glacier and Glacial Channels across the Chicago Divide’’ 
presented to the Geological Society of Chicago, October 30, 1890. Ed, 
A box was constructed 8 ft. long, 3 ft. high, and 10 inches 
wide, to represent a valley. The inclination of the box was 
slight, about six inches in the eight feet. The bottom of this 
box (large A in the cut) extended about three feet beyond the 
box at the upper end, fora fulcrum for the lever K. The box 
had no cover and but one end, (small A) which was designed to 
represent the upper end of the valley and also aid in applying 
the pressure required to move the ice. Through this head a slot 
or mortise was cut, 3x10 inches, through which the piston D 
moved; this head also formed one side of the hopper or chute G 
which extended from one foot above the top of the valley to the 
bottom. This hopper or chute opened into the upper end of the 
valley directly in front of the piston D to which, through the 
agency of the lever K, a total foree of 1,500 pounds could be 
applied if necessary. The sides of the box were supported 
against the great pressure by several strongly bolted clamps. 
This box was then filled to the top with broken ice FF, and the 
*AMERICAN GEOLOGIST, Vol. IX, March 1892, p, 187. 
