1. E. I. du Pont de Nemours & Co., Inc., Explosives Department, Repauno Development Laboratory, Gibbstown, N.J., U.S.A., (T.A.B.) and Experimental Station Laboratory, Wilmington, Delaware, U.S.A. (R.S.)
2. School of Chemistry, The University of New South Wales, Box 1, Post Office, Kensington, 2033 Australia