Scientific amusements . cylinder it impingesupon one side of the holes in the rotating disc, and blowsit round. The disc in one revolution will therefore open and shutas many holes as there are in the disc and cylinder, andthe air blown in will escape in so many puffs—the numberof puffs in a given time depending upon the rapidity ofrotation. There is an arrangement to show the number SOUND FIGURES. 193 of turns. By these rotations a sound is produced whichrises in pitch as the revolutions are increased in number. To determine the pitch of a certain sound we mustfind the number of times the pla
Scientific amusements . cylinder it impingesupon one side of the holes in the rotating disc, and blowsit round. The disc in one revolution will therefore open and shutas many holes as there are in the disc and cylinder, andthe air blown in will escape in so many puffs—the numberof puffs in a given time depending upon the rapidity ofrotation. There is an arrangement to show the number SOUND FIGURES. 193 of turns. By these rotations a sound is produced whichrises in pitch as the revolutions are increased in number. To determine the pitch of a certain sound we mustfind the number of times the plate revolves in that time,then we-shall have the number of vibrations per secondrequired to produce the note we desire. The arrangementworking in a notched wheel tells us the number of rotationsof the disc. Successive, and rapidly-successive puffs orbeats are lieard as the rotation increases, and at lengththe two sounds will disappear, and merge into one, whichis perhaps that of the tuning-fgrk, whose note you require.
Size: 1574px × 1588px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade189, booksubjectscientificrecreations
