Hans Pizka wanted information about the Hogon-horn. Luckily,I wrote the definitive article about this instrument for the New Grove Dictionary of Music (12th Edition). No doubt you are delighted that I have condescended to share my expertise.
The Hogon-horn is a horn with an extra-large boar at each end. Although the classical Hogon-horn lacked valves, the modern instrument has four cylindrical rooters. Wagner specified a quartet of Hogon-horns for his operas Das Schweingold, Grunterdaemmerung, and, of course, the Frying Dutchman.
Despite its porcine appearance, the Hogon-horn has a very finicky appetite. Mine for example, will turn up its snout unless I offer it a rare kind of Baviarian truffle known as a Wagner Tuber.
Composers have avoided writing concerti for the Hogon-horn, although Schumann requested four of them (!) in his exciting (but nearly unplayable) Concertstunk. Even so, the Hogon-horn has never caught on as a full-fledged member of the modern symphony oinkestra.
For additional information, I advise you to visit the Web pages of that renowned Hogon-horn virtuoso, Thomas Bacon.
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Cabbage