1. Direction Cosines (/) of a Line in Space (/) DCOS. A date reads: Jan 18-1945 (/) Wellesley May 1945. Threre are six pattern pieces, each in metal and in paper. A lined sheet of paper, dated Jan ...

THIS work, which is primarily a formal treatise on the differential geometry of curves, surfaces, and threefold regions in ordinary homaloidal space of four dimensions, follows fairly closely on ...