1. 1) The expenses for the present series of experiment were defrayed by the Grant in Aid for Scientific Research from the Ministry of Education.
2. 2) H. Erdtman and J. Gripenberg: Nature, 164, 316 (1949).
3. 3) J. W. Cook, A. R. Gibb, R. A. Raphael, and A. R. Somerville: J. Chem. Soc., 1951, 503.
4. 4) E. Sebe and C. Osako: Paper read before the 4th Annual Meeting of the Chemical Society of Japan in April, 1951. (To be published).
5. 5) Analyses were carried out by Messers. Hirai and Kawamoto of the Sankyo Co., Ltd.