The Probert Encyclopaedia of Music

CORNET

The cornet is a treble wind instrument made of brass, of comparatively recent origin. It was formerly called a cornopean. It is played with a cupped mouthpiece, and possesses a quality of tone which comes between those of the trumpet and the bugle, the size of its tube being intermediate to those used for these instruments. Three slides are employed which lengthen the tube to produce intermediate tones.
Research Cornet