Post horn

The post horn is a valveless cylindrical brass instrument with a cupped mouthpiece. The instrument was used to signal the arrival or departure of a post rider or mail coach. It was used by postilions of the 18th and 19th centuries. The post horn is sometimes confused with the coach horn, and even though the two types of horn served the same principal purpose, they differ in their physical appearance. The post horn has a cylindrical bore and was generally used on a coach pulled by two horses (technically referred to as "Tonga"); hence, it is sometimes also called the Tonga horn. The coach horn, on the other hand, has a conical bore and was used on a coach pulled by four horses (referred to as a "four-in-hand"). The post horn is no more than in length, whereas the coach horn can be up to long. The latter has more of a funnel-shaped bell, while the former's bell is trumpet-shaped. Post horns need not be straight but can be coiled—they have a smaller bore —– and they are made entirely of brass. A post horn will have a slide for tuning if intended for orchestral settings. The instrument is an example of a buisine, a precursor to the "natural" trumpet. The cornet was developed from the cone-shaped coach horn through the addition of valves, while the cylinder-shaped trumpets remained predominantly valveless for several decades. In the late 17th century, Johann Beer composed a Concerto à 4 in B, which paired a post horn with a corne de chasse as the two solo instruments, accompanied by violins and basso continuo. Mozart composed his Serenade No. 9, the "Post horn Serenade", in 1779. The second trio of the 6th movement, the Menuetto, features a solo of the posthorn. Mahler and others incorporated the post horn into their orchestras for certain pieces. On such occasions, the orchestra's trumpet player [performing on a post horn] usually performs with the instrument. One example of post horn use in modern classical music is the famous off-stage solo in Mahler's Third Symphony.