The electron, its isolation and measurement and the determination of some of its properties

by Robert Andrews Millikan

and average these

-displacements. The latter procedure is evidently the more reliable, since the former must assume the exact identity of the particles.

APPENDIX D
THE INERTIA OR MASS OF AN ELECTRICAL CHARGE ON A SPHERE OF RADIUS

Fig. 40

If [Fig. 40] represents a magnet of pole area