(Scraped wheels - cog rattles or Ratchet)
A ratchet, also called a noisemaker or Knarre (German) (or, when used in Judaism, a gragger or grogger (etymologically from Yiddish: ?), raganella or ra'ashan (Hebrew: ?)), is an orchestral musical instrument played by percussionists. Operating on the principle of the ratchet device, a gearwheel and a stiff board are 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 were used to warn of poison gas attack in the trenches of the First World War and issued to British police and ARP wardens during the Second World War, to warn of the presence of poison gas.
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 symbolically drown out his name (although every word of the Megillah, including Haman's name, must be heard clearly; therefore, the words are often repeated after the sounding of the gragger). The gragger was developed to help make noise during the reading.
A Purim gragger, a kind of ratchet used in Judaism
Police whistles came much later; the early Victorian constable would have carried a small wooden rattle.
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.