?

to apply sufficient pressure to raise a little
valve. Particulars of this invention of the
Englishman Barker, which considerably facili-
tates playing, even with couplers, will be
found in Töpfer, vol. i. p. 542 and following,
and in Richter, chap. xiv. Latterly Pneumatic
Action has been successfully applied to Com-
bination Pistons (q.v.).

Pneumatic Combination Pistons (buttons)
have, particularly in England, and lately also
in Germany and Switzerland, been placed
above or below the corresponding manual.
When pressed by the finger they push out a
group of stops attached to them, without
interfering with the organist's previous ar-
rangement of stops. In this place should
be mentioned the so-called stop key-board,
which in some organs takes the place of the
buttons.

Portunal Flute. An exceedingly rare open

wood flue pipe of 8-ft. and 4-ft. tone; which,
meaning Bordunal Flute, is undoubtedly de-
rived from Bordun.

Principal (Fig. 8), called Montre in French,
is the chief flue stop, found without excep-
tion on every organ. It is always made of
the best material (see Gamba), and forms,
tastefully arranged in front (see Electro-
pneumatic Action), the chief outer ornament,
as well as the foundation for the whole
tuning. The most approved way of build-
ing a Principal pipe is to make it of pure

FIG. 8.

Principal. Pitch coincides with that of the same length Gamba in Fig. 1, which is of slender scale in order to obtain the Gamba string-tone.

English tin, giving it a high silvery polish. (See Fistula.) If an organ has two or more manuals the Principals are made of different dimensions. On an organ of two manuals, for instance, the Principal of the Great manual is of wide scale, and that of the upper manual of smaller scale (Geigenprincipal, q.v.). On medium or small organs, the Diapason of the Great manual is always of 8-ft. tone; that is to say, the lowest note of this row of pipes-getting smaller as they ascend-is about 8 ft. (An exception is made in the case of front pipes, which are lengthened in order to obtain symmetry of outline, and are cut open behind at the point where the pipe proper ends.) I met with an 8-ft. Principal in my travels, which, owing to limited space, was arranged acoustically for the lowest manual tones with the 8-ft. Gedackt, and with a mellow wooden 4-ft. octave stop, and I did not discover great disadvantage arising from this combination. Very large organs often have both a 16-ft. and an 8-ft. Principal on the first manual. In the organ of St. Denis, by Cavaillé-Coll, is found a rare specimen, viz. a 32-ft. Principal on the second manual, which latter is sometimes called the Great manual (Paris, Geneva, and others). On the pedals the Principal is found, even in medium-sized organs, as a 16-ft. stop. As an exception I found, on a very good organ in Jersey, an open 16-ft. pedal stop, labelled Grand Open Pedal, which alone counterbalanced the three manuals. This stop resembles in size and power the corresponding pedal stop in the church of St. Laurence at St. Gallen (the latter organ presents the peculiarity of extraordinarily large keys). This peculiar proportion of the pedal stops is also found in large American organs. An arrangement by Roosevelt (New York), for example, only shows one Principal Bass of 16 ft.,

one Sub-Bass of 16 ft., and one Violoncello of 8 ft., amongst 33 speaking stops. In the largest organs the 32-ft. Principal Bass is made of wood, seldom of metal. The widest scale Principal pipe of 32 ft., when made of metal, weighs 41 cwt. (specimen : Hofkirche, Lucerne), and has a diameter of about 18 inches, and a circumference of about 5 ft. According to Töpfer (vol. ii. p. 200), an open 32-ft. Principal pipe requires 1536 cubic inches of wind per second for the C"; the c' requires 994, and the c""" 64 cubic inches per second. Open 32-ft. Principal Bass stops of wood (in some churches erroneously labelled Sub-Bass) are of more frequent occurrence. In most cases, the weight of C, in such a giant pipe, is about 8 cwt., with sides of 2 inches thickness, so as to be able to oppose sufficient resistance to the vibrations of the column of air. The sides of organ pipes are not absolutely motionless; the vibration of the sides can be distinctly felt as soon soon as the pipe is blown. As the physicist Zamminer, however, says, it is necessary to enclose the air in resisting walls, so that powerful vibrations may be obtained; if they are slack and yielding the motion communicates itself through the sides of the pipe to the surrounding atmosphere, and the vitality of the undulation is annihilated before it reaches the other end of the tube. (See Combinations of Stops and Flue Stops.)

Probe Tin. See Gamba.

Progressio is a non-repeating stop, more nearly described under the head of Mixture.

Progressio Harmonica. See Harmonica.

Prolongement. (1.) Combination Prolongement. By means of this pedal, arranged for instance on Walcker's giant organ at Riga, the organist is enabled to keep on the combination of stops already chosen, whilst he prepares any

E

other set, which can then, at any given moment, be drawn in place of the former set. (2.) Prolongement Harmonique is a contrivance worked by a pedal or stop, which prolongs the sound of the notes struck on the manuals, even after the fingers have left the keys (for instance, during a pause) and are occupied in combining another set of stops (arranged in Cavaillé-Coll's Exhibition organ, 1878). The effect of this prolongement lasts until the pedal or stop releases the keys of the manual.

Q.

Quint is a well-known mutation stop, which has for object the strengthening of the second upper partial. It appears as an open stop with the dimensions of a Principal, and its tubes are cylindrical; but it may also occur cone-shaped, and is then called Gemshorn, Spitzquint, or Nassatquint. The length of the Quint stop is 10% ft. (32), 53 ft., 23 ft., and 13 ft., and depends upon the corresponding Principal. The Quint of the 16-ft. Principal is 103 ft., that of the 8-ft. Principal 5 ft.; the Quint of the 4-ft. Octave is 23 ft., and of the 2-ft. Octave 13-ft. I should here mention the invention of Court Kapellmeister Abt Vogler (died 1814, at Darmstadt), who found, by using the tones discovered by Sorge and named after Tartini (differential tones, the origin of which Helmholtz has explained), that in sounding simultaneously a 10% Quint and a 16-ft. Principal a 32-ft. tone is produced, and that in sounding simultaneously a 51-ft. Quint and an 8-ft. Principal a 16-ft. tone is obtained. It is evident that by avoiding an actual construction of the lowest open Basses, 32-ft. and 16-ft., a considerable amount of material is saved (see end of article on Principal). This so-called simplification

system of Abt Vogler's is sometimes employed (for instance, for the acoustical 32-ft. tone in Glarus), and I have often recommended it as a valuable aid (particularly in cases where the height of the church did not permit of any other arrangement). This is the place in which to mention Walcker's interesting combination of the acoustical 32-ft. Grand Bourdon on the Votiv organ at Vienna; this stop is composed of 16-ft. Principal Bass, 8-ft. Octave Bass, and 4-ft. Octave Bass, combined with 103-ft. Quint Bass and 63 Great Tierce. Gottschalg says of these five pedal Basses-in reality a 5-rank giant pedal mixture-that, thanks to their construction, they combine to a single tone, which, in point of roundness, distinctness, and power, leaves nothing to be desired. They are mounted on a separate sounding-board, which is very responsive. A covered Quint stop fitted with a chimney is called Rohrquint. (See Rohrflöte.) Like the mixtures, Quint belongs only to the Great Organ. (See Octave for the numeric proportions of the simple intervals to their foundation tone.)

Quintaten allows the fifth, that is, the twelfth above the octave, to be very softly heard at the same time as the prime; hence the name of Quintam tenens (see Helmholtz, p. 152), that is, holding the fifth. Quintaten may possibly have been derived from the medieval Latin quintadenare, French quintadiner (Allihn). The Quintaten, belonging to the family of the Gedackts, owes this quality to its materially narrow scale. On the upper manuals the Quintaten is of rich, voluminous tone, and when built by a master forms an ornament to any organ. Among organs of modern date, I mention the great Sydney organ, by Hill and Son, in which the 16-ft. Quintaten, placed on the Solo Organ, will be of valuable service. The Madeleine, Paris, possesses a very rare