Tyndall, John, 1820-1893 · New York : D. Appleton and company · leaf 98
ss oblique-ly through the top ofthe cylinder c, and alsoobliquely, but opposite-ly inclined, through therotating disk d e. Theair is thus caused to is-sue from c, not verti-cally, but in side cur-rents, which impingeagainst the disk anddrive it round. In this way, by its passage through thesiren,… … SOUND. pair of toothed wheels (see when the back of the instru-ment is turned toward you). As the disk and its axisturn, these wheels rotate. In front you simply see twograduated dials, Fig. 28, each furnished with an index likethe hands of a clock. These indexes record the number ofrevolutions…
Sound
Internet Archive · California Digital Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Graphophone patents] (1878)](https://img.insideoutlibrary.com/img/200/ia-graphophonepaten10unit-561-378.webp)