FLUTES.
The chief developments in Flutes that have taken place during the period under consideration are the popularization of the double length, or "Harmonic," principle,[4] by Cavaillé-Coll, by William Thynne and others, and the introduction of large scale leather-lipped "Tibias" by Hope-Jones.
Harmonic Flutes, of double length open pipes,[5] are now utilized by almost all organ builders. Speaking generally, the tone is pure and possesses considerable carrying power. Thynne, in his Zauber Flöte, introduced stopped pipes blown so as to produce their first harmonic (an interval of a twelfth from the ground tone). The tone is of quiet silvery beauty, but the stop does not seem to have been largely adopted by other builders. Perhaps the most beautiful stop of this kind produced by Thynne is the one in the remarkable organ in the home of Mr. J. Martin White, Balruddery, Dundee, Scotland.
The Hope-Jones leathered Tibias have already effected a revolution in the tonal structure of large organs. They produce a much greater percentage of foundation tone than the best Diapasons and are finding their way into most modern organs of size. They appear under various names, such as Tibia Plena, Tibia Clausa, Gross Flöte, Flute Fundamentale and Philomela.
"The word Tibia has consistently been adapted to the nomenclature of organ stops on the Continent (of Europe) for some centuries. The word Tibia is now used in this country to denote a quality of tone of an intensely massive, full and clear character, first realized by Mr. Hope-Jones, though faintly foreshadowed by Bishop in his Clarabella. It is produced from pipes of a very large scale, yielding a volume of foundation tone, accompanied by the minimum of harmonic development. Even from a purely superficial point of view, the tone of the Tibia family is most attractive; but, further, its value in welding together the constituent tones of the organ and coping with modern reed-work is inestimable." [6]
"The Tibia Plena was invented by Mr. Hope-Jones, and first introduced by him into the organ at St. John's, Birkenhead, England, about 1887. It is a wood Flute of very large scale, with the mouth on the narrow side of the pipe. The block is sunk, and the lip, which is of considerable thickness, is usually coated with a thin strip of leather to impart to the tone the requisite smoothness and finish. It is voiced on any wind pressure from 4-inch upwards. The Tibia Plena is the most powerful and weighty of all the Tibia tribe of stops. It is, therefore, invaluable in large instruments. * * * The Tibia Profunda and Tibia Profundissima are 16-ft. and 33-ft. Pedal extensions of the Tibia Plena." [7]
"The Tibia Clausa is a wood Gedackt of very large scale (in other words, a stopped pipe), furnished with leather lips. It was invented by Mr. Hope-Jones. The tone is powerful and beautifully pure and liquid. The prevailing fault of the modern Swell organ is, perhaps, the inadequacy of the Flute work. * * * It was the recognition of this shortcoming which led to the invention of the Tibia Clausa." [8]
The Tibia Dura is another of Mr. Hope-Jones' inventions. It is an open wood pipe of peculiar shape, wider at the top than the bottom, and described by Wedgwood as of "bright, hard, and searching" tone.
The Tibia Minor was invented by Mr. John H. Compton, of Nottingham, England, one of the most artistic builders in that country. "The Tibia Minor bears some resemblance to Mr. Hope-Jones' Tibia Clausa, but being destined more for use on an open wind-chest, differs in some important respects. The stop is now generally made of wood, though several specimens have been made of metal. In all cases the upper lip is leathered. The tone of the Tibia Minor is extraordinarily effective. In the bass it is round and velvety * * * in the treble the tone becomes very clear and full * * * it forms a solo stop of remarkably fine effect, and in combination serves to add much clearness and fulness of tone to the treble, and, in general, exercises to the fullest extent the beneficial characteristics of the Tibia class of stop already detailed. If only by reason of the faculty so largely exercised, of thus mollifying and enriching the upper notes of other stops—which too often prove hard and strident in tone—the Tibia Minor deserves recognition as one of the most valuable of modern tonal inventions." [9]
The Tibia Mollis, invented by Mr. Hope-Jones, is a Flute of soft tone, composed of rectangular wooden pipes. The name Tibia Mollis is also employed by Mr. John H. Compton to denote a more subdued variety of his Tibia Minor.
Other Flutes found in organs are the Stopped Diapason, Clarabella, Clarinet Flute, Rohrflöte ("Reed-flute"), Wald Flöte, Flauto Traverso, Suabe Flute, Clear Flute, Doppel Flöte (with two mouths), Melodia, Orchestral Flute, etc., each of a different quality of tone and varying in intensity. The Philomela as made by Jardine is a melodia with two mouths.