Abstract
In a recent paper Mastellcr and Bauer (1978, henceforth referred to as MB) report some observations of the faceting, on a macroscopic scale, of grain boundaries in aluminium bicrystals. It is the purpose of this note to compare the resulb of MB with some other recently published results on grain boundary faceting in gold (Goodhew, Tan and Balluffi 1978, Allen and Goodhew 1977) and to comment both on the limitations of the techniques and the interpretation of the observations.