Since low-angle boundaries consist of simple dislocation arrays, a study of their properties should provide valuable information on dislocation behavior. Parker and Washburn demonstrated that a low-angle boundary moves as a unit when subject to a shear stress, in complete agreement with what would be expected for a linear dislocation array. It has also been found that the boundary angle decrease with increasing distance of shear. This means that the boundary loses dislocation as it moves, a fact which would be expected if dislocations were held up at imperfections such as foreign atoms, precipitated particles, and other dislocations.