Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/899

ORGAN 833 In organs which have no solo manual there is usually a clarionet (cremona, cromorne, or krummhorn, in old organs sometimes corno di bassetto) on the choir, and often an orchestral oboe (real imitation of the instrument). These are reed-stops. The dulciana and another soft stop, the salicional, salcional, or salicet (of similar strength, but slightly more pungent quality), are often placed on the choir. They are, however, hardly strong enough to be of much use there, and in the swell they are useful for effects of extreme softness. In very large instruments a fifteenth and a mixture are sometimes placed on the choir, which in this case has a complete series of diapason work. If the fifteenth and the mixtures are light enough the result is a sort of imitation of the tone of the old English organ. It also forms a useful echo to the great organ, i.e., a passage played on the great may be repeated on the similar but fainter tone of the choir with the effect of an echo. In instruments of the largest size the choir is sometimes pro vided with a very small bourdon of 16 foot tone, which helps to give to the tone the character of that of a small full organ without reeds. olo The solo organ is comparatively modern, at all events rgan. m fa present usual form. A fourth manual was not un known in old German organs ; but the contents of all four resembled each other in a general sort of way, and there was nothing like the English swell or the modern solo. The solo appears to have arisen with Cavaille-Coll in France, and Hill in England, as a vehicle for the powerful reed-stops on heavy wind introduced by these builders. Thus the French term for the solo is " clavier des bom- bardes " ; and in the earlier English solos the " tuba mira- bilis " was usually prominent. A solo organ may suitably contain any of the following stops : 8 tromba (a powerful reed on heavy wind), 8 harmonic flute (powerful tone and heavy wind), 8 clarionet and 8 orchestral oboe (real imi tations of the instruments), and 8 vox humana (conven tional imitation of the human voice). The vox humana is sometimes placed in the swell. The last three stops are reeds. They may be with advantage enclosed in a swell box, having a separate pedal. In very large instruments a complete series of both diapason and reed stops is occasionally placed on the solo. But there does not seem to be much advantage in this arrange ment. edal We now come to the pedal. This forms the general bass TKO.II. to the whole organ. Thirty-two foot stops only occur in the largest instruments; they are as follows: 32 open diapason (wood or metal), 32-foot tone bourdon, and 32 contra trombone, posaune, bombarde, sackbut (reed). The 32-foot open diapason, whether wood or metal, is usually made of large scale, and produces true musical notes throughout. Its musical effect in the lower part of its range is, however, questionable, so far as this depends on the possibility of recognizing the pitch of the notes. It adds great richness to the general effect, particularly in large spaces. The 32-foot tone bourdon is not usually a successful stop. It rarely produces its true note in the lower part of its range. The 32-foot 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 lately, 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 giving 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 16-foot pitch may be regarded as the normal pitch of the pedal ; .the principal stops are as follows : 16 open diapason (wood or metal), 16-foot tone bourdon, 16 violone (imitation of double bass), and 16 trombone or posaune (reed). The 16-foot 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 moder ate 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 suit ably provided. Where metal pipes are made a feature in the organ-case, both the double open diapason in the great organ and the metal 1 6 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-foot 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 1 6-foot 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-foot tone. The 16-foot reed is very common. The observations made as to the effect of 32 -foot reeds are applicable also in this case. The 8-foot 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-foot pedal-stops are as follows : 8 principal bass (metal or wood), 8 bass flute (stopped), 8 violon cello (imitation of the instrument), and 8 trumpet. The remarks made above as to the scale of open 16s apply with little change to the pedal principal. Only, since the manuals are generally coupled, it is perhaps best to pro vide the large scale wood-stop, which presents the power ful class of tone in which the manual diapasons are deficient. The bass flute is almost a necessity in combina tion with the light 16-foot 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-foot trumpet serves to give clear ness and point to the tone of the 16-foot reed. In the short preface to Mendelssohn s Organ Sonatas it is stated that everywhere, even in pianissimo, it is intended that the 16-foot tone of the pedal should be accompanied 1 Anything down to one-third tin and two-thirds lead is called tin. But "pure tin" should have over 90 per cent, of tin. Absolutely pure tin could not be worked. Spotted metal is said to hnve 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. XVII. 105