Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity (1854)
Davis, Daniel · Boston : Palmer and Hall · leaf 231
, in addition, an arrangementfor striking a bell, which isfixed above the magnet. Tothe axis of the revolving baris attached an endless screw ;this screw acts on a toothedwheel, which is provided witha pin projecting laterally, forthe purpose of moving thehammer. As the wheel turns,the pin presses… … ROTATION BY EARThs ACTION. 215 341. If the wheel has 100 teeth, as in the cut,the electro-magnet must revolve 100 thnes in orderto produce one revolution of the wheel, and con-sequently one stroke upon the bell. The velocityof the rotating bar is measured by counting thenumber of strokes in a given…
