Lectures on light, delivered in the United States in 1872-'73; with an appendix (1873)
Tyndall, John, 1820-1893 · New York, Appleton · leaf 58
n the puffs suc-ceed each other with sufficient rapidity, the impressionsupon the auditory nerve link themselves together to a PITCH.—ACTION OF THE SYREN. 53 continuous musical note. The more rapid the rotationof the disk the quicker is the succession of the impulses,and the higher the pitch of the… … In front of our lamp now stands a very homelyinstrument S, Fig. 4, of this character. The per-forated disk is turned by a wheel and band, and, whenthe two sets of perforations coincide, a series of spotsof light, sharply defined by the lens L, ranged on thecircumference of a circle, is seen upon…
Optics
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer03inte-213-124.webp)
