The Probert Encyclopaedia of Music

FRENCH HORN

The French horn is an orchestral brass transposing instrument, developed from the hunting horn. It consists of a coiled tube with a wide bell and a cup-shaped mouthpiece. In the 18th century crooks of tubing were inserted to enable it to change a key. In the 19th century valves were fitted giving the horn in F a complete range of about three octaves above B below the bass stave.
Research French Horn