This page has been validated.
COLLECTED PHYSICAL PAPERS
365
The friction of the writing point against the smoked glass surface, however, introduces serious error in the accurate record of the amplitude and time-relations of the response-curve. The difficulty has been overcome by the writer being thrown into resonant vibration in
Fig. 115. Diagrammatic representation of the Recorder.
V. one arm of lever attached to leaf; W. the writer. The falling plate during descent makes electric contact of R with R′, causing induction-shock by the secondary coil S. Stimulus applied at a causes response later, at b.
consequence of which the record consists of a series of dots; the error arising from friction of continuous contact is thus completely avoided.
The Resonant apparatus consists of the writer, made of fine steel wire tuned in different cases, to vibrate
