and sackbut family of instruments, a relative of the modern trombone (Colwell and Goolsby 402). The slide extends the overall length of the instrument, usually five to seven semitones, which allows the performer to play the twelve tones of the western scale throughout much of the range of the instrument (Ibid.). The slide trumpet has fallen out of favor, despite a revival in England in the 1800's, and is not performed unless specifically called for by the composer (Yates, "History").
             The valve revolution began in the late 18th and early 19th centuries. The invention is credited to Heinrich Stölzel and Friedrich Blühmel. Stölzel applied his valve design to the horn in July of 1814. Blühmel applied his valve design, known as the box or Berlin valve, in 1817/18 (Ericson, "Why").
             Figure 1. Stölzel Valve. Figure 2. Horn with Stölzel valves & crooks.
             Figure 3. Blühmel (Box) Valve Figure 4. Horn with Berlin valves
             There is speculation about the intent of the inventors of the valve mechanism. One school holds the belief that it was intended to eliminate the need to change crooks while maintaining a natural horn sound- the full chromatic possibilities were apparently an afterthought. In the competing school, it was the intention of Stölzel and Blühmel to perfect a fully chromatic brass instrument. Regardless of the intention, the crook and natural horn were out of favor with composers and performers by the end of the 19th century (Ericson, "Why").
             These two valve types were the precursors to further advancements in valve design. The valves used in contemporary brasses include the Périnet (improved) piston valve, the rotary valve, and the Vienna (double piston) valve (Ericson, "Early"). There are other mechanisms, used mainly by trombonists (the Thayer, balanced rotor, Greenhoe, Hagmann, and others)...