A Dictionary of Music and Musicians/Composition Pedals
COMPOSITION PEDALS. As up to within the last century English organs were quite unprovided with pedals, the notes required to be played had to be lowered exclusively by the fingers of the two hands; and as a hand could rarely be spared for changing the combination of stops during the performance of a piece of music, the same stops that were prepared previously to its commencement had generally to be adhered to throughout. When the instrument had two manuals of full compass, as was the case with all the most complete examples, a change from forte to piano, and back, was practicable, and represented almost the full amount of contrast then available; and the departments which are now called the 'great' and 'choir' organs were then not unfrequently named from this circumstance the 'loud' and the 'soft' organs. When the organ possessed but one complete manual, the means for even this relief, either by change of row of keys or shifting of stops by the hands, were not readily presented; and this difficulty pointed to the necessity for some contrivance for obtaining it by the foot; and the invention of the 'shifting movement,' as it was called, was the result.
Father Smith's smaller organs, generally consisting of a Great manual of full compass and an echo to middle C, were usually supplied with an appliance of this kind. On depressing the controlling pedal all the stops smaller than the principal, including the reed, were silenced; and on letting it rise they again sounded, or at least so many of them as had in the first instance been drawn. The pedal was hitched down when in use, and when released the sliders were drawn back into position by strong springs.
Shifting movements remained in use for small organs up to the commencement of the present century, about which time they were superseded by the late Mr. Bishop's invention called 'Composition Pedals,' in which the contending springs were done away with, and the stops were left to remain as the pedal arranged them until another pedal, or a hand, made a readjustment. We can now say a 'hand,' because a few years before the invention of Mr. Bishop's appliances pedals for drawing down the lower notes of the manuals had been added to English organs, so that a hand could be spared for the above purpose.
Composition pedals were of two kinds—single-action and double action; but the latter only are now made. A 'single-action' would either throw out or draw in given stops, but would not do both. A 'double-action' composition pedal will not only draw out a given number of stops—we will suppose the first four—but will draw in all but the same four.