1. Barnóthy and Forró, Z. Phys., 104, 744 (1936).
2. Maass, Ann. Phys., v, 27, 507 (1936).
3. Prof. Blackett has kindly pointed out to us that a certain part of this difference may be due to scattering. This question can only be settled by further experiments.
4. Yukawa, Sakata and Taketani, Proc. Phys. Math. Soc. Japan, 20, 319 (1938). Frohlich, Heitler and Kemmer, Proc. Roy. Soc., A, 166, 154 (1938).
5. Kemmer, Proc. Camb. Phil. Soc. (in the Press).