on the right (a a) contains highly compressed air derived from a reservoir, the lever carrying the valve v, which cuts off the communication between this chamber and the one immediately above it, works through an air-tight leather joint (b b) in the centre, the left-hand end of the lever moves the double exhaust valves e e, and is attached to the extremity by a tracker (t) to the tail of the key. On raising this end of the lever li, the valve v is opened, admitting the pressure from the chamber a a to the chamber immediately above, and thence to the interior of the power bellows p p P, which thus become inflated; simultaneously the exhaust valves e e are closed, and prevent the exit of the compressed wind, as the top-board of the power bellows rises it draws up the throttle valve x x, which is attached to it, so that on this valve's reaching the seat provided for it, it cuts off any further supply of compressed air to the power bellows, and thus checks their motion almost noiselessly. The movement

of the top board of the power bellows is communicated to the sound board pallets by the usual train of mechanism. On releasing the key the lever is returned to its normal position by the spring s. The precision of the action is greatly enhanced by the auxiliary spring z, which closes. the exhaust valves e e at the very first depression of the key, thus preventing the high pressure wind from running through when the lever is at half action.

Such is the arrangement applied to each note of a manual, these little systems being arranged in frames arranged one above the other the same width as the manuals, and placed as near them as possible.

Having detailed the principle and one form of the original pneumatic lever, we must, in justice to modern builders, point out that frequent improvements and modifications have been and are continually being adopted. For instance, almost all pneumatic actions are now con

structed on the exhaust system, i.e., in place of high pressure powerbellows containing compressed air, the wind is exhausted from these small bellows, so that the same result is produced on the mechanism by exactly the reverse modus operandi. This method has been adopted as it was found that the continual strain on the ribs of the power-bellows was more than could with convenience be overcome; whereas the exhausting of these caused no such strain. The manner in which this exhaust is produced is by reversing the position of the valves of the

feeders, viz., placing those that are usually above the bottom-board

FIG. 34. BRYCESON'S PNEUMATIC PALLET.

below it, and by hanging the weights under the feeder instead of placing them on the top-board.

Perhaps one of the best modifications of the pneumatic lever is that introduced by Messrs. Bryceson Brothers, who, under the title of the "Pneumatic Pallet," have patented an ingenious method of obviating much of the complication found in the old form of this action.

Fig. 34 shows a section of this arrangement: A A A is the soundboard bar, immediately under which is the face of the pallet (B) as usual in ordinary action; c c are the ribs of the pallet; D D represents a double action lever valve, which, be it understood, is inclosed in the pallet

itself, and is unseen under ordinary circumstances; E E is a chamber of attenuated air; F is the well of the sound-board containing compressed air; G is a metal rod passing through the metal brass plate H to lift the end of the lever valve, either by the armature of an electro-magnet, or by the ordinary mechanical action; I is the usual sound-board spring, which keeps the face of the pallet close against the sound-board bar, at the same time keeping the exhaust end of the lever valve closed; K is the aperture through which the compressed air enters the pallet when the lever valve is opened; L is an opening affording exit for the compressed air to pass out when the lever valve is open at that end, as also for the passage of the rod &, which acts on the lever valve from the action without the pallet; the small spring м is of great importance, inasmuch as it presses on a portion of the lever valve divided from the rest by a hinge so as to prevent the aperture at K opening until the hole L is almost closed.

The action of this arrangement is most easily understood. When the pallet is at rest the valve is in the position shown in the diagram. On pressing the key, the position of the lever valve is reversed by the rod G. That is, the aperture K is stopped, and the opening at L being free, an amount of exhaust is created in the actual pallet itself sufficient to at once open the passage to the pipes. On releasing the key the hole L is closed, and that at K being opened, the compressed air forces the face of the pallet up against the sound-board bar. Thus the amount of resistance offered by the pneumatic pallet is obviously extremely small. The spring I is only sufficiently on the L side of the lever valve to keep the hole well closed. All seriously inconvenient pressure must, if it exist at all, arise from causes external to the pallet, and must be treated accordingly by electric or other agency. The great importance of the spring м will be appreciated when it is observed that were it not for that, during the change of position at the lever valve, the compressed air in the chamber F would tend to neutralise the exhaust in the chamber E by rushing in before the valve was well closed. It may be almost said that the weight of the top-board of the pallet is enough to open on the pressure being cut off, and it is found in practice that very slight exhaust is sufficient to accomplish this.

The pneumatic pallet has been found to answer not only in combination with the electric action, but also as a perfect substitute for the more complicated "pneumatic lever." The large organ at the ProCathedral, Kensington, is fitted with these on the "swell" and "great" respectively, and we can, from personal experience, assert that a more easy, crisp, or pleasant touch we do not know. The pipes answer with a marvellous accuracy and rapidity, and the mechanism has gone

through a lengthened and somewhat hard trial without requiring repair or even attention. This speaks volumes for the invention, as it is a practical trial of the most severe description, the music at this church being often of an unusually elaborate character.

It will not be necessary to again refer to the pneumatic systems until we come to the draw stop action, where this power is made of frequent and important use.

In the succeeding chapters we shall treat of the electric action in its entirety, and somewhat fully, for the importance of this branch of the builder's work is becoming every day more and more felt by all who watch or study the arts in connection with music.

CHAPTER VIII.

The Electric Action.

THE name Barker was mentioned more than once in connection with the introduction of the pneumatic lever, and although great praise is due to Mr. Barker for his labours in relation therewith, it is not his ingenuity in that field that gained for him his greatest honours. We mentioned the active part this gentleman took in the Paris Exhibition of 1855, and must go on to state that, after the retirement of M. Ducroquet, he remained with his successor, M. Merklin, until 1860, when he started on his own account with M. Verschneider as his partner, the latter being an excellent voicer, and having won his spurs by the perfect manner in which he arranged the harmonisation of the grand organ at St. Eustache, then considered one of the best in Paris.

After what has been said of the pneumatic lever apparatus, and the modifications thereof, it might be supposed that nothing more was to be gained by further invention; but it would seem that in no application of machinery has perfection in a strict sense been obtained, and it is obvious that the jump from the pneumatic to the electric action is far greater than that from the old mechanical arrangements to the pneumatic system. One great defect of the organ, especially noticeable in instruments of a large size, with several key-boards, is the number and excessive complication of its mechanical parts, all of which, however accurately adjusted, are, from their nature, particularly subject to the effects of atmospheric changes, thus, under the influence of damp, the long trackers shorten, the various levers swell, and move with difficulty ou their bearings; the solid framing which supports the sound-boards by its variation, adds to the general disorder, and "cypherings" are the unfortunate result. Every organist is aware that in summer the touch of his instrument is reduced to a minimum, and is often totally inadequate to open the pallets enough to supply sufficient wind to the pipes, by which means the organ is rendered out of tune, and, consequently, painful to the ear. To remedy as far as possible these serious defects, the mechanical actions are provided with regulating screws (vide

G