1. Anonymous, Bur. Standards, Circ.3, 89 pp. (1918).
2. Ibid., p. 32.
3. Anonymous, Bur. Standards, Test-Fee Schedule225, 2 pp. (Aug. 1, 1932).
4. Anonymous, Z. angew. Chem.37, 861 (1924).
5. Association of Scientific Apparatus Makers, U. S. A., Ind. Engng. Chem.17, 1014 (1925).