1. U. S. Dept. of Agriculture Circ. No. 366, Aug., 1935.
2. Amer. Paint J.,22, 44, Aug. 8, 1938, p. 7.
3. Private Comm., Petroleum Specialties Co., St. Louis, Mo.
4. Private Comm., Pacific Coast Chemical Co., San Francisco, Calif.
5. Laboratory Letters, Spencer Kellogg and Sons Inc., Buffalo, N. Y.