1. For references to the earlier literature see, Leonard B. Loeb, Static Electrification, Springer-Verlag, Berlin, 1958.
2. C. A. Evans, Jr. and C. D. Hendricks, Rev. Sci. Instr. 43, 1527 (1972).
3. D. S. Simons, B. N. Colby, and C. A. Evans, Jr., Int. J7-Mass Spectrom. Ion Phys. 15, 291 (1974).
4. B. P. Stimpson and C. A. Evans, Jr., Rimed. Mass Spectrom. 5, 52 (1978).
5. B. P. Stimpson, D. S. Simons, and C. A. Evans, Jr., J. Phys. Chem. 82, 660 (1978).