Tuba rotary-valved tubas pitched in the same octave as euphoniums. The "Small Swiss Tuba in C" is a tenor tuba pitched in C, and provided with 6 valves to make the lower notes in the orchestral repertoire possible. The French C tuba was the standard instrument in French orchestras until overtaken by F and C tubas since the Second World War. One popular example of the use of the French C tuba is the "Bydło" movement in Ravel's orchestration of Mussorgsky's "Pictures at an Exhibition", though the rest of the work is scored for this instrument as well. Larger BBB subcontrabass
Brass instrument valve by Heinrich Stölzel in 1815) was an early variety. The piston valve found in the majority of valved brass instruments was invented in 1838 and patented in 1839. They are sometimes called Périnet valves after their inventor, François Périnet. They work by diverting air obliquely through ports in the stock of the valve so that a loop of tubing is included in the air stream, lowering the pitch. The stock of the valve is cylindrical and moves up and down through a larger cylindrical casing. The rotary valve works using a short circular plug housed in a larger cylindrical casing.