Abstract

One of the chief defects of the “speaking arc” as used by H. Th. Simon in 1898, was its failure to reproduce in a satisfactory manner high-pitched tones. This failure was obviously due to the thermal inertia of the arc.

The minuteness of the mass of the electron, and for that matter of the atom, suggested the substitution of an ordinary discharge tube for the electric arc. A tube of special construction containing a trace of a mixture of helium and neon was used and the substitution met with marked success, the high notes coming through much more clearly than in the case of the arc, sibilants like s and c being distinguishable from one another and voices being recognizable. Quantitative comparisons furthermore confirmed the superiority of the discharge tube over the arc.

© 1926 Optical Society of America

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