(Scraped wheels – cog rattles or Ratchet)
A ratchet, also called a noisemaker (or, when used in Judaism, a gragger or grogger (etymologically from Yiddish: גראַגער) or ra'ashan (Hebrew: רעשן)), is an orchestral musical instrument played by percussionists. Operating on the principle of the ratchet device, a gearwheel and a stiff board is mounted on a handle, which rotates freely.
The player holds the handle and swings the whole mechanism around. The momentum makes the board click against the gearwheel, producing a clicking and rattling noise. A popular design consists of a thick wooden cog wheel attached to a handle and two wooden flanges that alternately hit the teeth of the cog when the handle turns. Alternatively, smaller ratchets are sometimes held still or mounted and the handle turned rapidly by the player. The mounted ratchets allow for greater control of the duration and timing of the sound. This allows the ratchet to be used like a snare drum, placing sustained rolls in precise durations of time. Dynamics are controlled by the rate at which the ratchet is rotated. 
The ratchet is similar to a football rattle, which is sometimes used in its place when a particularly loud sound is needed. It is used in, for example, Richard Strauss's piece Till Eulenspiegel's Merry Pranks and Arnold Schoenberg's Gurre-Lieder. In the 18th and 19th centuries, a similar device called a policeman's rattle was used by British and Australian policemen to summon assistance. They also used the device during the Second World War, to warn of the presence of poison gas.
Use in Jewish tradition
In Judaism, the gragger is used for the holiday of Purim. The gragger is used every time Haman's name is mentioned during the reading of the Megillah. Because Haman persecuted the Jews, the noise is supposed to drown out his name. The gragger was developed to help make noise during the reading.
In some European traditions, ratchets are used in celebrating Easter Day
A Purim gragger, a kind of ratchet used in Judaism
- Derkach, a Ukrainian version of the ratchet.
- Karl Peinkofer and Fritz Tannigel, Handbook of Percussion Instruments, (Mainz, Germany: Schott, 1976), 152-153.
- Cross, David (2011-02-17). "On the Beat in Birmingham - Rules and regulations". BBC. Retrieved 11 March 2014.
Police whistles came much later; the early Victorian constable would have carried a small wooden rattle.
- "Evolution of the Victoria Police uniform". The Australian. Retrieved 11 March 2014.
Police rattle from the late 19th century. Used by early police officers in Melbourne, to call for assistance or sound warnings... Later replaced by a whistles.
- Taylor, J. "The Victorian Police Rattle Mystery" The Constabulary (2003)
- Lincolnshire Special Constabulary Bulletin No. 27 - September, 1942.
- Einstein, Stephen J.; Kukoff Lydia (1989). Every person's guide to Judaism. URJ Books and Music, ISBN 978-0-8074-0434-8
- Karesh, Sara E.; Hurvitz, Mitchell M. (2006). Encyclopedia of Judaism. Infobase Publishing, ISBN 978-0-8160-5457-2
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