notes, and the length of time needed to change crooks, did greatly limit their usefulness. The addition of valves around 1815 by Heinrich Stölzel and Friedrich Blühmel revolutionized the playing of many brass instruments and the music that could be written for them. The name "valves" is somewhat misleading since what is involved is that the crooks have become a permanent part of the instrument, and are opened and closed in various combinations by the use of valves, rendering the switching between crooks effectively instantaneous (see also the articles on the French horn, the cornet, and the valved trumpet). Hybrid instruments In the 19th-century, brass instruments were produced which incorporated many of the features described above in one design. For instance, the National Music Museum has a German (or Austrian) trumpet in G (NMM 7077), ca. 1840, which includes terminal crooks, two-piston valves, and a tuning slide. The museum also has a cornet (cornopean in B-flat, Raoux, Paris, ca. 1850, NMM 6852) with terminal crooks, Stölzel valves, tuning slide, and tuning shanks, one of which was also used as a coupler. Modern Vienna horns are manufactured with a detachable F crook, and occasionally B or A crooks are substituted. See also Cité de la Musique, home of the Musée de la Musique, Paris Extension (music) References Sources External links Richard Seraphinoff, Natural Horns, Handcrafted Historical Reproductions of Baroque and Classical Natural Horns. Brass instrument parts and accessories