In music the cornet is a wind instrument of the brass family, closely related to the trumpet. like the trumpet, the cornet plays a chromatic scale by means of three piston valves operated by the performer's fingers. Its tonal quality is controlled mainly by the lips, and the pitch is determined mainly by the valves. The cornet is most often pitched in B flat, but it is a transposing instrument that plays a whole tone below its indicated pitch. Its range is about 2½ octaves, from F sharp on the bass staff to C above the treble staff.
   Although the cornet has about the same amount of tubing as the trumpet, it has a wider and more conical bore, a more flaring bell, and a deeper and more cup-shaped mouthpiece than the trumpet's. As a result its tone is more mellow than the ringing brilliance of the trumpet. Because the lip technique and fingering of the two instruments are basically the same, the trumpet and cornet are often used interchangeably in modern bands and orchestras.
   The cornet developed from the small post horn of the early 19th century. Its first use as a two-valved instrument is believed to have been in Paris about 1829. The cornet achieved its present form a few years later, when a third valve was added.