1. M. Schwartz:Bull. Am. Phys. Soc., II,1, no. 7, 319 (1956). This work is more fully described in a paper to be published soon byM. Schwartz.
2. At the completion of this paper, a recent note byVallarta, Gall andLifshitz has come to our attention (Phys. Rev.,109, 1403 (1958)). These authors have considered the influence of the quadrupole component of the earth’s magnetic field on the simple shadow cone for several values of latitude, longitude and magnetic rigidity. They get results very near to ours, and attribute the discrepancy with Schremp to the quadrupole component. Our work shows that in fact this discrepancy is mostly due to serious errors in Schremp’s work.
3. G. Lemaitre andM. S. Vallarta:Phys. Rev.,49, 719 (1936).
4. E. J. Schremp:Phys. Rev.,54, 153 (1938).
5. E. J. Schremp:Phys. Rev.,54, 158 (1938).