Sir,

Professor Nye is right and ! apologize. I do not remember whether 1 intended to say “...Icelandic jokulhlaups might proceed ...” instead of “should proceed” or if my wrong assertion came from nos reading again Reference NyeNye’s (1976; paper before writing mv introduction. Anyway, my sentence should not refer to jokulhlaups and read: “According to Reference NyeNye (1976), an irreversible broadening of the water veins can occur if the pressure difference between the ends of the vein is fixed."

The essential point is that Nye’s stability analysis of water discharge through capillary veins was unsound, because capillary and salinity effects were ignored. Nye applied to veins Rothlisberger theory for large waterways. In this theory, melting at the w’alls comes only from the energy loss due to the water discharge. For capillary veins, this term, as well as the shrinking by plasticity, are totally negligible. The heat flux that reaches the walls is almost ex-clusively (with my notations’:

where and By arc the temperatures within the ice at the lenses walls and at the veins walls, respectively Both are governed by interi’acial energies and respective salinities. The heat llux would exist without any water discharge. A stable regime exists, however, because for some vein size #l = #v-

Reference NyeNyc’s (1976) “contradicts” Reference Nye and MaeNye and Mae (1972) because it ignores the important findings of this previous work. Ii was clearly asserted in the abstract: “Internal melting and freezing at grain boundaries and veins will occur in temperate glacier ice, with some effect, not discussed here, on its permeability to water* My paper affords this missing discussion and shows that it is not “some"cffcct; it turns to be the essential one.

Laboratoire de Glaciologie el Geophysique Louis LLIBOUTRY

de I’F.mirounemcnt,

F-38402 Saint-Martin-d’Heres Cedex,

France

26 March 1997