A Dictionary of Music and Musicians/Slide (brass instruments)
SLIDE (Fr. Coulisse; Ger. Zugstange, Stimstück; It. a tirarsi). A contrivance applied at a very early date to instruments of the trumpet and trombone family, for lengthening and shortening the sounding tube, and thus filling the gaps between the fundamental note and its successive harmonics. Two slide-trombones, essentially identical with the modern pattern, are to be seen, one in the Museo Borbonico at Naples, the other in the Queen's collection at Windsor. Both were found at Pompeii. [Trombone.] In the trombone the mouthpiece, upper joints, and bell of the instrument are held to the mouth of the player by means of the left, while the slide is held and adjusted by means of the right hand and arm. In the G bass trombone, the length of a man's arm not being sufficient to reach the lower slide positions, a jointed handle is fixed to the cross-bar of the slide by way of prolongation. In the trumpet, the extent of travel of the slide being far less, and that instrument being held in the right hand, the slide is placed between the bell and the upper part of the tube, and drawn to its closed position by a spiral spring, or an elastic ligature of caoutchouc. It is drawn out to the required length by the fore and middle fingers, acting in opposition to the thumb.
A double slide-action on the principle of the trombone has been very ingeniously applied to the French Horn by Mr. Ford. It is actuated by a key somewhat resembling the usual rotatory valve apparatus. It is patented, and a model has been deposited in the Museum of Patents at South Kensington. It of course has the inestimable advantage which causes the slide trumpet and trombone to excel all other wind instruments in accuracy of intonation—that namely of producing the notes by ear and not by an unalterable mechanism; but it has never been adopted by musicians.