Glow-curves of ice, made in the laboratory, have a distribution of peak-height ratios, with the maximum at approximately 0.75. The distribution was probably caused by varying conditions of crystallization, impossible to control with the present equipment. Glow-curves of ice which has been made to flow have a distribution of peak ratios with the maximum at approximately 1.75.
It is concluded that dislocations in the crystal lattice effect the peak ratio. Dislocations are produced during crystallization by internal stresses, and to a greater extent, by external forces during the flow.