1. 1) (a) I. Nitta and T. Watanabé: Nature, 140 (1937) 365, Sci. Papers Inst. Phys. Chem. Research Tokyo, 34 (1938) 1669;
2. (b) Llewellyn, Cox and Goodwin: J. Chem. Soc., (1937) 883.
3. 2) I. Nitta, S. Seki, and K. Suzuki: Bull. Chem. Soc. Japan, (in press).
4. 3) Ebert: Ber., 64 (1931) 114.
5. 4) I. Nitta and T. Watanabé: Bull. Chem, Soc. Japan, 13 (1938) 28.*) I. Nitta and T. Watanabé: (unpublished data).