1. Part of the results published in this paper have been presented at the IUPAP Conference for Cosmic Rays held in Moscow, July 1959.
2. T. Sándor, A. Somogyi andF. Telbisz:Suppl. Nuovo Cimento, in press.
3. L. Jánossy andG. D. Rochester:Proc. Roy. Soc., A183, 786 (1944).
4. L. Jánossy, T. Sándor andA. Somogyi:Suppl. Nuovo Cimento,8, 701 (1958).
5. T. Sándor, A. Somogyi andF. Telbisz:Acta Phys. Hung.,11, 205 (1960).