30 R. W. Wood, Jr. — Effects of Pressure on Ice. 



Art. Y. — Effects of Pressure on Ice / by R. W. Wood, Jr. 



Certain theories regarding the movements of the great 

 glaciers of the ice epoch, depending on the pressure- melting 

 of ice, a number of experiments were performed by the 

 writer, to determine the effect of great pressures on ice masses 

 at various temperatures. The experiments were tried with a 

 hydrostatic press capable of yielding a pressure of one hun- 

 dred tons on its 6J inch ram, the first one being made to deter- 

 mine at what pressure ice could be made to flow through a 

 tube of small diameter. 



A block of iron was cast measuring 6x4x4 inches, and 

 drilled to the depth of four inches with an If inch hole, to 

 which was fitted a solid steel piston, turned with such accu- 

 racy that, when oiled, it worked air-tight except under con- 

 siderable pressure, when a few bubbles oozed through. Into 

 the side of the block a T Vth inch hole was drilled, which com- 

 municated with the bottom of the cylindrical cavity precisely 

 like the vent of a cannon. The cavity was nearly filled with 

 ice at the melting point, and the steel piston inserted. The 

 apparatus was then put under pressure : for a minute or two 

 water flowed from the hole, with occasional air bubbles which 

 effervesced with a white foam on emerging. The index of the 

 guage showed that the ram was exerting a pressure of about 

 six tons (three tons to the inch, the piston being two square 

 inches in cross section) when the ice began to rise through the 

 small hole. It rose slowly and steadily at first, as a cylinder 

 of clear ice, which broke off when six or eight inches in 

 height, then faster as the pressure increased, until the gauge 

 indicated a pressure of nine tons, when it seemed fairly to 

 spurt from the orifice, pieces two or three inches long being pro- 

 jected to a height of a foot or more into the air. It flowed 

 with an irregular motion, which did not correspond with the 

 strokes of the pump, but seemed to indicate that the ice was 

 in a viscous condition, seeming to stick for a second or two 

 and then yield suddenly. On reversing the press, and remov- 

 ing the piston, what was left of the ice was found moulded 

 into a clear transparent block. 



The next experiment was to test at what pressure ice at the 

 melting point would become fluid as a mass. An iron block 

 similar to the one used in the previous experiment, except that 

 it was without the small hole, was filled with ice in which 

 were imbedded several small bullets, the positions of which 

 were carefully noted. The piston was fitted and the mass sub- 

 ected to pressure. The index showed a tension of fourteen 



