Word of the day
police whistle
A simple whistle typically made of metal and used by police in the late 19th and early 20th century to communicate within urban neighborhoods. It was invented in 1884 by Acme Whistles. This whistle is also known as a pea whistle, because it has a pea (actually cork or synthetic cork) in the chamber of the whistle. The pea moves around the chamber with the turbulence of the air blown into the whistle. This turbulence constantly changes the pitch of the whistle and creates a rapid trill that is louder and more piercing than a whistle without a pea.
The police whistle has been used as a special effect in musical compositions for many years, but is well known as a signaling device for marching bands.