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Until recently the means provided to effect this coupling was called the "tumbler " movement. But a great objection to its use was, that if brought into action whilst playing on the lower manual there was a tendency to throw the fingers off the keys or disarrange the mechanism. These drawbacks have been overcome by the "gliding" coupler (Fig. 48). It will be seen that here the great organ key, &, has been cut on the upper surface, so as to leave an inclined plane, I, which is covered with leather, and then black-leaded that it may be perfectly smooth. The under surface of the swell-key s is grooved in a like manner, i. When not in action the sticker, s s, drops into the register, r r. The great organ key, G, can then rise without coming into contact therewith. When in action, the register, R R, is carried backwards to the position

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it assumes to the right of the figure. The sticker, s s, glides up the inclined plane, 1, is raised slightly out of the register, R R, and brought under a button, b, and thus lifts the swell key, s. The back part of the sticker is so bevelled that should the coupler be drawn when a great organ key is down, the sticker may raise the swell key by degrees without any sudden jerk. A tapped wire, w, passes through the swell key and regulates the action of the coupler to a nicety.

The same contrivance is used to couple the swell or the great organ to the choir in unison. An octave coupler affecting notes of another keyboard may either be made to act on separate pallets of the soundboard, or by means of backfalls on the ordinary key action. In the former case the keys would not be pulled down when the coupler is

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brought into play; whereas, in the latter instance, if not specially weighted, the notes of the coupled manual would descend. The same holds good with regard to the sub-octaves.

The coupling of the pedals to the manuals is accomplished by the aid of rollers, backfalls, and stickers. The rollers are required to bring the pedal note under that corresponding to it on the manual, and

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this portion of the action being accomplished, a backfall (B Fig. 49) runs parallel to the manual key, a a. From the end of this backfall a sticker, c c, rises, supported in a frame, d. When the manual is not coupled, the sticker frame is in such a position that the tail of the key,

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E

d

FIG. 50. SFORZANDO PEDAL.

A, is just free, and in front of the sticker, c, as in Fig. 49; but by drawing a knob attached to suitable mechanism, the frame, d, is put slightly forward, and the sticker, c, is placed immediately under the key, A, as shown by the dotted lines.

When the pedal key is depressed, the tracker, E, pulls down the backfall, B, raises the sticker, c, and with it the tail of the manual key, a a,

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This same action may be used for all unison coupling of the pedals to a manual, a separate set of stickers being required for each distinct clavier with which the connection is to be set up. Couplers are frequently made to bring notes of a different pitch on the manuals in connection with given notes on the pedals. Thus a cc pedal may bring down a tenor c of the manual, and by so doing obtain the effect of as many 4ft. stops on the pedal as there are unison or 8ft. stops drawn on the manual during the time of coupling. Another useful coupler is that which causes the pedals to act on various octaves of their own clavier, as when the cc key brings down the c with it, or the c key brings down the cc.

The sforzando pedal is a coupler of great value. It is an arrangement for bringing the power of the great organ on to the swell manual instantaneously by means of a pedal. Occasionally, where there is a sub and super-octave coupler acting on the swell organ, these are brought on instead of the great, and inasmuch as then the whole reinforcement is again under the influence of the ordinary swell pedal, this method is perhaps the better. Fig. 50 shows the mechanical contrivance for bringing the great organ under the control of the swell keys. This is accomplished by means of a backfall, E, which rises and falls on the sticker, f, and thus connects the action of the swell tracker, c, with that of the great tracker, d; the upper pin of the sticker is free, the under one being regulated by a button, g. On depression of the swell key, A, the backfall, E, will so act on the sticker, f, that the tail of the great organ key, B, is lifted. A spring brings the pedal back into its original position when the foot is removed, and moves the backfall, E, from its bearing point on the sticker, f.

Composition Pedals or Shifting Movements.

WHEN a considerable number of stops differing in character were placed on the same manual, a difficulty arose in so adjusting the drawknobs that they might be immediately under the control of the performer, in order that an instantaneous change from loud to soft music, or vice versâ, could be effected. This was more especially felt in small organs having no echo. Both Smith and, after him, Snetzler met this defect by having a pedal so arranged that on its depression all the louder stops were silenced, and with its release were brought on again. As a rule this pedal would take off whatever mixture might exist, together with the reed, and any flue stops under 4ft. tone. The pedal was held down in a notch, and was brought back by a more or less powerful spring, which was made to act on the sliders that were in connection with the mechanism or on the pedal itself. Such a contrivance remains as Snetzler left it in the organ at St. Decuman's, Somerset (vide Part I., Chap. IV.), which in this case acts on a cornet, sesquialtera, and fifteenth.

The modern composition pedals or shifting movements are an improvement on the spring pedal, and are attributed to the late Mr. Bishop. At first each pedal was constructed to perform one function only, i.e., to pull out or draw in a given number of sliders. These were termed single-action composition pedals. The spring, which, in the original arrangement of Smith's time, threw the sliders into their former position, was dispensed with, so that if a pedal drew out knobs 1, 2, and 3, another pedal or the hand was required to replace them. These single-action movements have been entirely superseded by the double-action pedal, which finds a place in all modern instruments. These are so constructed that each pedal not only draws out given stops but at the same time pushes in all others, so that by a single movement the organist is sure of obtaining one individual combination, whatever the condition of the sliders may have been

previous to the transition. Supposing three pedals to act on the sliders. of the great organ; if all the stops are in, and the first pedal be depressed, the diapasons and principal would be drawn; on the action of the second pedal, the metal flue stops up to the fifteenth would be added with perhaps a thin mixture, the third pedal would bring on the full mixtures and reeds. If all the stops are drawn and the first pedal be pressed, all stops except the diapasons and principal would be silenced.

As a rule, organs of moderate size are now provided with at least four double-action composition pedals acting on stops of the great manual, the first giving a soft organ of, say, stopped diapason and dulciana, the second rising to the principal, the third to the small flue stops with the quint, and the fourth commanding the full organ. It is also usual to have three or more of these pedals acting on the swell, especially where there are many stops in this department. In large two-manual instruments it is more than ever necessary to have well arranged composition actions, that the choir and soft organ effects can be promptly brought to bear; in fact, these movements in a great measure palliate the absence of a choir manual for soft accompaniments, though the advantage of the extra clavier for solo effects needs no comment.

The shifting movement has been applied lately to large organs in an extremely useful manner. Under each manual, and well within reach of the thumbs, are placed a number of buttons acting by pneumatic agency on the sliders after the manner of the composition pedals. The mechanism, as far as the pneumatic arrangement is concerned, is a modification of that in use for regulating single sliders (vide Chap. IX.) The advantages of this plan are manifold; for not only is a mere touch sufficient to rearrange the stops, but the performer has each button in sight, and these being immediately under the manual they influence, there is no tendency to confusion of relationship.

The ordinary mechanical shifting of the sliders can be effected in so many ways that each builder chooses a method in accordance with his surrounding work; and it is here again frequently a matter of the individual peculiarity of an instrument that will decide which is the best mode of procuring the desired result. Fig. 51 shows a very useful form of action. The sliders, s s, s s, are attached by the armlets, a a, to the rods, rr, R R, which are fixed so as to revolve on their axes. The crank,

c, is connected to the rod, r r, and by the projecting irons, p p, acts also on Ꭱ Ꭱ. When the pedal, P, is put down the rod, r r, is turned forty-five degrees, and the sliders, s s s, are thrown in, whereas the rod, R R, is forced forty-five degrees in the opposite direction by the projecting irons, p p, and the sliders, s s s, are drawn out.

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