Page:EB1911 - Volume 20.djvu/294

It rarely produces its true note in the lower part of its range. The 32-ft. reed on the pedal has long been a characteristic of the largest instruments. With the old type of reed it was rarely pleasant to hear. The manufacture has been greatly improved, and these large reeds are now made to produce a fairly smooth effect. Deep reed notes, when rich and good, undoubtedly form one of the principal elements in gii'ing the impression of power produced by large organs. From this point of view they are of great importance. Nevertheless the effect of large pedal reeds is generally more satisfactory to the performer than to the listener.

The l6-ft. pitch may be regarded as the normal pitch of the pedal; the principal stops are as follows: 16 open diapason (wood or metal), i6-ft. tone bourdon, 16 violone (imitation of double bass) and 16 trombone or posaune (reed). The 16-ft. open diapason on the pedal assumes different forms according to circumstances. As a rule the character is sufficiently indicated by the stop being of wood or metal. The wooden open is generally of very large scale, and produces a ponderous tone of great power and fulness, which is only suitable for the accompaniment of the full organ, or of very powerful manual combinations. Such a stop is, as a rule, unsuitable in organs of moderate size, unless supplemented by lighter 16s for ordinary purposes. The metal open is of considerably smaller scale (in fact all metal pipes are effectively of much smaller scale than wooden pipes of similar diameter). The metal gives a clear tone, lighter than that of large wooden pipes, and pleasanter for ordinary purposes. The metal open combines advantageously with a bourdon. In the largest organs both wood and metal open 16s may be suitably provided. Where metal pipes are made a feature in the organ-case, both the double open diapason in the great organ and the metal 16 of the pedal may be properly made of good metal (polished tin or spotted metal), and worked in to the design of the organ-case.^[1] The same applies to the 32-ft. metal opens of the largest instruments. This saves space in the interior, and gives the large pipes room to speak, which is apt to be wanting when they are placed inside. The 16-ft. tone bourdon on the pedal may be made of any scale according to circumstances. If it is the chief bass of the organ it is made very large and with great volume of tone. Such stops are unsuitable for soft purposes, and a soft 16, usually a violone, is required in addition. If the loud department of the 16 tone is otherwise provided for the bourdon may be made of moderate strength. It may also be made very soft, like a manual bourdon. These three different strengths ought always to be provided for in an instrument of a complete character. The violone is also made of all three strengths. In a few cases it furnishes the principal bass; frequently it furnishes the moderate element; and it is often applied to obtain a very soft 16-ft. tone. The 16-ft. reed is very common. The observations made as to the effect of 32-ft. reeds are applicable also in this case.

The 8-ft. department of the pedal is only less important than the 16, because it is possible to replace it to a certain extent by coupling or attaching the manuals to the pedals. The usual 8-ft. pedi-stops are as follows: 8 principal bass (metal or wood), 8 bass flute (stopped), 8 violoncello (imitation of the instrument) and 8 trumpet. The remarks made above as to the scale of open i6s apply with little change to the pedal principal. Only, since the manuals are generally coupled, it is perhaps best to provide the large scale wood-stop, which presents the powerful class of tone in which the manual diapasons are deficient. The bass flute is almost a necessity in combination with the light 16-ft. tone. A composition ought to be provided by which the pedal can be reduced to these two elements by a single movement. The violoncello is sometimes used instead of the bass flute for the last-named purpose, for which, however, it is not so suitable. It is a favourite stop for some solo purposes, but is not of much general utility. The 8-ft. trumpet serves to give clearness and point to the tone of the 16-ft. reed.

In the short preface to Mendelssohn's Organs Sonatas it is stated that everywhere, even in pianissimo, it is intended that the 16-ft. tore of the pedal should be accompanied by 8-ft. tone. For the purpose of realizing this as a general direction the soft 16-ft. arid 8-ft. stops are required; large instruments are, however, occasionally found which possess nothing of the kind.

The following stops of higher pitch are occasionally found on the pedal: 5½ twelfth bass, 4 fifteenth bass, mixture and 4 clarion. These serve to make the pedal tone practically independent of coupling to the manual, which is a matter of great importance, especially in the performance of certain compositions of Bach and other writers, who appear to have been independent of couplers.

In some instruments two sets of pedals are provided, which may be described as great and choir pedals. The great pedal is in the usual position; Second Pedal the choir pedal is in front of the other, and sloping, it is so placed that the feet rest on it naturally when stretched out in front of the performer. There is a choir pedal of this kind in the organ in the minster at Ulm, built by Walcker of Ludwigsburg. It is a very large instrument, having 100 sounding stops. It has no compositions, which indeed are but little known in Germany; and without some arrangement such as this a soft pedal would hardly be obtainable. There are a few other instruments which have choir pedals, but they have not been introduced into England.

Arrangement of Manuals In organs which have a single manual the characteristics of the great and choir organs are usually united. In organs which have two manuals the lower usually represents the united great and choir, the upper is the swell, in organs which have manuals the lower is usually the choir, but sometimes combines choir and solo, the middle is the great, and the top is the swell. In organs which have four manuals the order is solo, swell, great, choir, the solo being at the top and the choir at the bottom.

Compositions are mechanical contrivances for moving the stop handles in groups at a time. The ordinary form consists of pedals, which project from the front just above the pedal keys. The arrangements are various. Compositions. We may refer to the in the organ at Windsor, given later on. A species of composition was introduced by Willis some years ago, and has been adopted in many large English instruments, which acts by means of a series of brass disks placed just under the front of the keys of each manual, within reach of the thumb. These act by means of pneumatic levers. A slight pressure on one of the disks sets the machine attached to it in action, and the required change in the stops is made without any exertion on the part of the performer.

General mechanism. The connexion between the keys and their pallets is made by various mechanisms, some of which are very ancient. In square and tracker work (fig. 7)

Fig. 7.—A, square, B, tracker; C, metal square.

the old squares were made of wood. They resemble in function the squares used for taking bell-wires round a corner. The trackers are slight strips of wood, having screwed wires whipped on to their ends, which hold by leather buttons. The trackers play the part of the bell-wires. Where pressure has to be transmitted instead of a pull, thin but broad slips of wood are used, having pins stuck into their ends to keep them in their places. These are slickers (fig. 8). Backfalls (fig. 9) are narrow wooden levers turning on pins which pass through their centres.

The fan frame (fig. 10) is a set of back falls having one set of ends close together, usually corresponding to the keys; the other ends are spread widely apart. The roller board (fig. 11) is a more general mode of shifting the movements sideways. The roller is a slip of wood, or a bit of metal tube, which turns on two pins inserted into its ends. It has two arms projecting at right angles to its length. One of these receives the pull at one point, the other gives it off at another.

In case a pull has to be transmitted to more than one quarter, a roller will sometimes have more than two arms.

The name of couplers (fig. 12) is given to the mechanical stop by which the keys of one manual are made to take down those of another, or those of the pedal to take down those of the manuals, borne old forms of the mechanism could not be put on while any of the keys were depressed;

An image should appear at this position in the text.

Fig 10.—Fan Frame.

others had a tendency to throw the fingers off the keys. These forms have been entirely superseded. That now used consists of a series of back falls centred on a movable support. The one set of ends is connected with the moving keys; the other set of ends is pierced by the wires of the trackers or stickers from the keys to be moved. In the one position of the support these ends play freely over the wires; in the other they are brought up against the buttons of the trackers or against the stickers to be moved. The usual couplers are — each of the manuals to the pedal, swell to great, swell to great octave, swell to great sub-octave, swell to choir, choir to great sub-octave, and solo to great. The swell octave and sub-octave couplers are sometimes placed on the swell itself. The

objection to this is, that if they are used when the swell is coupled to

1. Anything down to one-third tin and two-thirds lead is called tin. But "pure tin" should have over 90% of tin. Absolutely pure tin could not be worked. Spotted metal is said to have from one third to two-thirds tin. Under one-third tin no spots are said to rise, and the mixture has the general characters of lead.