Correspondence between John Nye and Joel Ellis Fisher Correspondence between Nye and Fisher concerning the extrusion flow theory of glacier movement. Nye had recently published a paper ruling out the possibility of free extrusion flow ['The Mechanics of Glacier Flow', Journal of Glaciology]. Fisher was a proponent of the extrusion flow theory and the correspondence contains several unsuccessful attempts to convince Nye that it could be occuring in glaciers. Includes a reprint of comments on Nye's paper published by Fisher in the Jounal of Glaciology, and Nye's response to them. April 1952-June 1952