as to receive them, and are hung on a rod of brass, which is fastened to the frame on their either side by small staples.

The trackers (Fig. 30), are long flat strips of pine about şin. wide and in. thick. At the lower end of the tracker is fixed a wire, which has a screw thread, on which runs a button of leather for the accurate adjustment of the tracker to the backfall (s, Fig. 30). The upper end is provided with a loop of copper wire for communication with the pull down of the pallet (c, Fig. 30,). The wire at the lower end of the tracker

is fixed by means of a slight hook at the upper end, being driven into or through the tracker, and the wire being bound firmly in place by strong thread, which is afterwards sized to keep it from coming undone.

The action of the fan frame movement is obvious; on pressing the key at A (Fig. 28), the end K rises and lifts the sticker s, which depresses the opposite end of the backfall B, and thus by means of the regulated position of the leather button, pulls down the tracker T, which is attached to the pallet pull down.

By this action each key communicates more or less directly with its corresponding pallet, but the key-board and grooves being parallel, it occurs that the sound board grooves, being wider than the separate keys of the clavier, that the movement could not assume parallel and direct lines from the one to the other, but that as they approached the ends they would be spread out and assume a more or less fan shape, according to the difference between the length of the sound board and that of the clavier; hence the title fan frame is connected with this kind of movement. It will be apparent that this simple mechanism can only be used for the third or fourth plans of arrangement (ante, Figs. 23 and 24), where the grooves of the sound board are distributed chromatically; and that even in the third plan exception must be taken for the lower octave, which is in this arrangement semi-tonal, to meet which contingency a roller is used, by which means each tracker is brought under its proper pallet.*

Fig. 31 shows an ordinary roller (R R), which is fixed by means of two

holders, called studs (H H), into the roller-board or frame (F F). The roller revolves on the centre pin, which is seen passing through the studs in the figure. At either end is placed a roller arm (A A), one end of which is immediately over the tail of the key, and the other directly under the front end of the backfall. These arms are connected by means of stickers to the keys and backfalls respectively. On the key being pressed the roller raises the end of the backfall, which pulls down the pallet in the ordinary

manner.

Rollers are arranged under each other in sets, and are now made of iron tubing, in lieu of the old fashioned wood, which was found to take too much room, and to be more liable to change. Each arm of the roller is well bushed to prevent any noise in action.

The roller movement, as the name would imply, requires a number of rollers in its construction. It is clear that in the arrangement of the grooves of the sound-board in the first plan (Fig. 21), which is the usual

Seeing that in this third plan all the keys of the bass octave are to be left in their usual position, whereas the alternate notes, six at least, are on the opposite side of the sound-board, these six or more keys would be quite away from the actual pallets they had to act on.

arrangement for large instruments, that whereas the c c and c c sharp keys are, of course, side by side, that their respective pipes would be at opposite ends of the soundboard; and in going through the scale in this plan this alternation continues. This difficulty is met by placing the backfalls parallel with each other, and bringing each under its individual pallet by means of a separate roller (as just described in the lower octaves of the third plan, where the fan-frame movement is used). This necessitates a great number of rollers, which are fixed in a frame and closely packed in layers. This frame is placed immediately under the wind chest, and extends almost the whole width of the soundboard. A glance at this action in an organ already built, will at once render its construction and action clear.

When the sound-board is too far back for the ordinary key action just described to reach conveniently, as in the case of choir organs or swells, a modification of the whole action takes place. Backfalls are dispensed

F

A

B

FIG. 32. THE SQUARE.

with, and squares inserted in their stead. These squares (Fig. 32) are centres made of wood, with two arms (A B) about 3in. long (these latter being occasionally of metal), the angle of the squares is let into a square frame (FF), and is hung on a metal rod, on which it can easily move in either direction. Squares should never be made in a solid piece, but by the junction of two distinct parts at least, as if made in the solid they are liable to give way with the strain, on whichever arm is cross-grained. The sticker acts on one end of the square, and to the other is fixed a tracker, which communicates with the rollers, varying in length, being 12ft., 14ft., 20ft., or even 60ft. in length. When made so very long, they are supported at various places throughout their length by bridges, which also prevent their becoming lax or intermingled. A square can transmit motion round any corner like an ordinary bell crank. This action, therefore, can by arrangement be made to meet almost any requirement.

CHAPTER VII.

The Pneumatic Action and Pneumatic Pallet.

IN Chapter V. we gave an idea of what the pneumatic action consisted -viz., an intermediate apparatus, which, being brought easily into action itself, had the power of doing a far greater amount of work than could with fairness be expected of the unassisted performer on the ordinary work, this holding good not only as regards its application to key action alone, but also with regard to draw-stop and other mechanisms.

Before describing this most useful and interesting attribute to our larger instruments, it will be in keeping to give briefly a few facts concerning its birth and history. Like many of our great inventions, there are several who lay claim to its original discovery, and again, like other inventions, it was not born in the flush of full-blown perfection; but, coming as an imperfected representation of a sound theory, has since been assiduously studied by those interested in its progress, and, being improved from time to time, has now reached a point at which it may fairly be said to answer present requirements as nearly as can be in reason desired.

The first attempts at relieving weight in action by means of small bellows were made simultaneously in 1827 by Mr. Joseph Booth, of Wakefield, an organ builder of some repute, on the one hand, and by Sebastian Erard on the other. Booth named his arrangements "puff valves," and Erard exhibited his "light touch valve" at Paris, in 1830. But in the same year Mr. Barker and Mr. David Hamilton, of Edinburgh, brought out independently of each other a pneumatic action, more nearly resembling those now in use; the latter gentleman reading a paper on his invention before the British Association, 1836.

Mr. Barker wrote to Dr. Camidge, then organist of York Minster, asking permission to apply his invention, in a temporary manner, to one of the heaviest keys of that large organ. Dr. Camidge encouraged the idea, and complained of the serious labour of playing on so large an instrument with all the manuals at full power and coupled. Unfortu

nately, the pecuniary question prevented its adoption in this instance, and he was not more successful in his proposition for its application to the Birmingham Town Hall organ opened in 1835.

In 1837 M. Cavaille, of Paris, was building a large instrument for the royal church of St. Denis, and the touch was so heavy that it seemed doubtful whether any organist of repute could be found who would hazard his reputation by attempting such difficult manipulation as would be necessary. Mr. Barker wrote to M. Cavaille, who at once jumped at the idea, and it was arranged that the former should himself superintend the construction of the mechanism in this instrument, for which purpose he went to Paris. He took out a French patent in 1839, and had the satisfaction of finding that the application of his invention was a complete success in this the first important trial thereof. After having this action introduced into several of the largest and best known Parisian organs, Mr. Barker joined the company of MM. Doublaine and Callinet, and his invention was frequently in request for their larger instruments. This company being dissolved in 1845, Mr. Barker carried on the business for M. Ducroquet, a capitalist, who had purchased the goodwill of the late company, and built for him many important instruments, prominently among which stands that of St. Eustache, and also the small but complete organ which appeared in the French department of the Great Exhibition of 1851, and for which M. Ducroquet received, in addition to the English prize medal, his nomination as Chevalier of the Legion of Honour.

There were in this exhibition two other organs with the pneumatic action, one by Mr. Willis, which also applied the invention to the drawstop action; and one by Mr. Hill, the latter applying the pneumatic arrangement to the drawstop mechanism only. From this date English builders began to appreciate the advantages to be derived from the pneumatic system, and mechanics from Paris were found in the English workshops, so that when Mr. Barker proposed to take out an English patent he found he had been forestalled.

In the Paris Exhibition of 1855 Mr. Barker was admitted as an exhibitor on his own account, and independently of M. Ducroquet, who was at that time retiring from business, but for whom he had built as a final specimen for this exhibition an organ of twenty stops, having three manuals and a separate pedal organ. In this instrument the pneumatic action was turned to good account, for it enabled Mr. Barker to place all the powerful reeds of the great organ in a swell. box, and thus obtain an unusually effective crescendo. At the close of this Exhibition Mr. Barker obtained a first-class prize medal, and was nominated Chevalier of the Legion of Honour. Figure 33 is a section of a single application of this invention as used in manual key actions. The lowest chamber