heads of the manuals to which they belong. The enumeration
will not be exhaustive, but will include all the usual types.
The great organ begins generally with stops of 16 ft. in large instruments. In some cases a 32-foot sounding stop is introduced, but this cannot be said to be a proper characteristic of the 0"^t great organ. The foundation tone is of 8 ft., the stops
orsaa. ^j higher pitch serve to add brilliancy; those of 16 ft.,
which sound the octave below the normal pitch, serve to add gravity and weight to the tone. Sixteen-foot stops are commonly spoken of as " doubles, " their conventional length being twice that of stops of normal pitch.
The i6-ft. stops are the 16 double open diapason, and the 16 bourdon or double stopped diapason, to which, in very large instruments, there may be added a 16 double trumpet. The double open diapason on the great organ consists usually of metal pipes, having moderate " scale, " or transverse dimensions. These are of the same general character as the pipes of the ordinary- open diapason, though they are made somewhat less powerful. In the better instruments of the second class as to size this stop alone would probably be regarded as representing suitably and sufficiently the class of doubles on the great organ. It gives great body to the general tone, and appears decidedly preferable to the bourdon, which frequently takes its place.
The 16 bourdon, when used on the great organ, is made of rather small scale and Ught tone. It gives great body to a large great organ and affords interesting combinations with other stops, such as the 4-ft. flute. It is used either alone in smaller organs of the second class, or in addition to a double open in larger instruments.
The 16 double trumpet is a trumpet (large reed stop) sounding the octave below the normal pitch. It is used generally in instruments of the largest size, but is somewhat more common in Germany. It is useful in giving a massive character to the tone of the full great organ, which is apt to become disagreeable on account of the great development of stops of a piercing character. If, however, the double trumpet is rough in tone, it is apt to communicate to the whole a corresponding impression.
We now proceed to the 8-ft. stops (the reeds come at the end according to ordinary usage). An ordinary great organ may contain 8 stopped diapason, 8 open diapason (one or more), 8 ^"'^* gamba and 8 hohlflote. The 8 stopped diapason on the
ft^fl great organ is usually of moderate scale, and some considerable fulness of tone. Few stops admit of more variety and individuality in their quality of tone than the stopped diapason; but too frequently the great organ stopped diapason fails to attract attention on its merits, being regarded simply as an inconsiderable portion of the foundation tone.
If there is any one stop which in itself represents the organ as a whole it is the open diapason. The pipes of this stop are the typical metal pipes which have always been characteristic of the appearance of the organ. A single open diapason stop is capable of being used as an organ of sufficient power for many purposes, though of course without variety. The pipes of this stop are called " principal " in German, this appellation apparently corresponding to the fact that they are the true and original organ-pipes. The English appellation of " diapason " has been taken to mean that these are the normal pipes which run through the whole compass. This, however, does not appear to be the actual derivation of the term; originally it is technically applied to the organ-builder's rule, which gives the dimensions of pipes; and it appears that the application to the stop followed on this meaning.
The scales, character and voicing of the open diapason vary with fashion, and are different in different countries. We may distinguish three principal types. The old English diapasons of the days before the introduction of pedal organs into England were characterized by a rich sweet tone, and were not very powerful. They were generally voiced on a light wind, having a pressure equivalent to that of a column of water of from 2 to 2^ in. The scale was in some cases very large, as in Green's two open diapasons in the old organ at St George's, Windsor; in these the wind was light, and the tone very soft. In other cases the scale was smaller and the voicing bolder, as in Father Smith's original diapasons in St Paul's Cathedral. But on the whole the old English diapasons presented a lovely quality of tone. English travellers of those days, accustomed to these diapasons, usually found foreign organs harsh, noisy and uninteresting. And there are many still in England who, while recognizing the necessity of a firmer diapason tone in view of the introduction of the heavy pedal bass, and the corresponding strengthening of the upper departments of the organ tone, lament the disappearance of the old diapason tone. However, it is possible with care to obtain diapasons presenting the sweet characteristics of the old English tone, combined with sufficient fulness and power to form a sound general foundation. And there can be no doubt that this should be one of the chief points to be kept in view in organ design.
The German diapason was of an entirely different character from the English. The heavy bass of the pedals has been an essential characteristic of the German organ for at least two or three centuries, or, as it is said, for four. The development of the piercing stops of high pitch was equally general. Thus foundation work of comparatively great power was required to maintain the balance of tone; the ordinary German diapason was very loud, and we may
Great
organ
4 feet.
almost say coarse, in its tone when compared with the old English diapason. The German stop was voiced as a rule on from 3j to 4 in. of wind, not quite twice the pressure used in England.
The French diapason is a modern variety. It may be described as presenting rather the characteristics of a loud gamba than of a diapason. In other words the tone tends towards a certain quality which may be described as " nasal " or metallic, or as approaching to that of a string instrument of rather coarse character. Some modern English builders appear to aim at the same model, and not without success.
The tone of a diapason must be strong enough to assert itself. It is the foundation of the whole organ tone. It is the voicer's business to satisfy this condition in conjunction with the requirement that the tone shall be full and of agreeable quality.
The 8 spitzflote may be regarded as a variety of open diapason. The pipes taper slightly towards the top, and the quality is slightly stringy. This stop was much used at one time in place of a second open diapason. But it appears better that, where two open diapasons are desirable, they should both be of full diapason quality, though possibly of different strengths and dimensions. The admixture of stnngy qualities of tone with the diapasons is always to be deprecated.
The 8 gamba was originally an imitation of the viola da gamba, a sort of violoncello. When made of a light quality of tone it is a pleasing stop; but its use in the great organ instead of a second open diapason is greatly to be deprecated for the reasons just stated.
The 8 hohlflote is an open flute, usually of wood, and of small scale. If made to a moderate scale and fully voiced it possesses a full pleasant tone, which is a useful support to the foundation tone of the great organ. The 8 clarabella differs from the hohlflote in being usually of rather large scale, and having the open pipes only in the treble. In old organs a separate bass was generally provided; now it is more usual to supply the stop with a stopped bass.
The 4-ft. stops of the great organ comprise the 4 principal and the 4 flute. The 4 principal is the octave of the open diapason, generally of somewhat reduced scale and light but bright quality of tone. The use of the word " principal " in connexion with this stop is purely English, and is said to be connected with the use made of it as the standard of tuning for the whole organ. The Germans and French both designate this stop as " octave."
Of the 4 flute there are several varieties — open, stopped, wood, metal and harmonic. The harmonic flute has open metal pipes of double the conventional length, which speak their octave. This is determined partly by the voicing, partly by making a small hole about the middle of the length, which determines the motion as that of the two separate lengths between which the hole lies. Harmonic flutes have a sweet but full and powerful tone. Other flutes are generally rather light, except the waldflote, which is a powerful stop of a somewhat hooting quality.
The great organ flute is frequently used to give brilliancy to light combinations. Thus it may be used with the stopped diapason alone, or with the 16 bourdon alone, or with any ^of these and either or both of the open diapasons.
The ordinary use of the 4-ft. stops is to add a degree of loudness to the diapasons. This is accompanied with a certain measure of keenness, which may become disagreeable if the 4-ft. tone is disproportionately strong. The ordinary practice is to use the 4-ft. tone very freely.
The 2§ twelfth stop sounds fiddle g on the C key. It is composed of diapason pipes, rather small and gently voiced. Its „ use is said to be to thicken the tone, which it certainly ** does. But how far the particular effect produced is °'^^ desirable is another question. It is generally necessary . .^ oHch that this stop should be accompanied by the fifteenth or other octave sounding stop of higher pitch.
The 2 fifteenth, or super octave, of the great organ consists of diapason pipes sounding notes two octaves above the normal pitch of the keys. The 2 piccolo is a fluty stop of less power, having the same pitch. The 2-ft. tone is commonly used as giving a degree of loudness to the great organ beyond that obtainable with the 4-ft. tone.
The modern great organ fifteenth is generally a very powerful stop, and requires great caution in its use in organs of moderate size, or in limited spaces. The old English high pitched stops had little power, and their brilliancy was capable of pleasing without offence. The modern great organ up to fifteenth can only be heard with comfort in very large spaces. Under such suitable circumstances the fifteenth is capable of giving to the whole tone a ringing or silvery character, which lends itself specially to contrast with the tone of reeds. This peculiar keen tone requires for its full development the mixtures.
Mixture, sesquialtera, furniture, cymbal, scharf, cornet, are various names applied to a description of stop which possesses several ranks or several pipes to each note. The pipes of each note sound a chord which is generally composed of concordant notes of the harmonic series whose fundamental is the proper note of the key. IModern mixtures generally consist of fifths and octaves. Their composition is not the same throughout the whole range of the keyboard. A
