1. Andersson, K. J. I., StÃllberg-Stenhagen, S., and Stenhagen, E., article in âœThe Svedberg 1884-30/8 1944â (Uppsala, 1944), p. 11.
2. The instrument used in the work described is a modification of that described in ref. 1. The monolayer is compressed symmetrically with respect to the Wilhelmy glass slide by two barriers moving in opposition to each other. This arrangement is necessary when very solid monolayers are investigated.
3. A very pure specimen of n-docosanoic acid (impurityp resent amounting only to a few parts per 10,000) obtained from Prof. F. Francis, Bristol, was used. Cf. Francis, F., and Piper, S. H., J. Amer. Chem. Soc., 61, 577 (1939).
4. Müller, A., Proc. Roy. Soc., A, 138, 514 (1932).
5. The nomenclature used by Harkins and Copeland, ref. 7, and Lifshitz, ref. 9, is employed.