Replicas showing slip lines on α-brass are examined with the electron microscope in order to decide whether slip in this metal is “homogeneous” or “inhomogeneous,” i.e., whether it takes place in atomistic steps on many successive atomic planes or in big steps on single atomic planes. The replicas used are subjected to a critical examination, to assess the reliability of measurements obtained from them. Five different methods are used. In four of these, slip lines selected at random are investigated, while in the fifth the average shear of all slip lines present on the portion of the specimen is deduced from that fraction of the surface which appears to be covered with slip lines when viewed perpendicularly. All five methods lead to the result that slip in α-brass is inhomogeneous.