1. The energy losses referred to in this section are energy losses caused by ionization. All energies and angles in this paper are in the laboratory system. All energy changes caused byQvalues of nuclear reactions or by recoil of residual nuclei need not be considered explicitly; their only importance is in determining Eb.
2. This simplification of Eq. (3) was pointed out to the author by E. L. Keller.
3. K. T. Bainbridge inExperimental Nuclear Physics, edited by E. Segrè (John Wiley & Sons, Inc., New York, 1953), p. 576.