[2] Barker was also associated with Péschard, who in 1864 patented jointly with him the electro-pneumatic action. (See page 37.)
[3] The pressure of the wind supplied by the old horizontal bellows is regulated by the weights placed on top. The amount of this pressure is measured by a wind-gauge or anemometer invented by Christian Förmer about 1677. It is a bent glass tube, double U shaped, into which a little water is poured. On placing one end of it fitted with a socket into one of the holes in the wind-chest (in place of a pipe) and admitting the wind from the bellows the water is forced up the tube, and the difference between the level of the surface of the water in the two legs of the tube is measured in inches. Thus, we always talk of the pressure of wind in an organ as being so many inches.
[4] The organ in Great Homer Street Wesleyan Chapel, Liverpool, England, had manuals extending down to CCC. It was built for a man who could not play the pedals and thus obtained 16 ft. tone from the keys. The old gallery organ in Trinity Church, New York, also has this compass.
[5] Tenor C is the lowest note of the tenor voice or the tenor violin (viola). It is one octave from the bottom note of a modern organ keyboard, which is called CC. The lowest note of the pedal-board is CCC. Counting from the bottom upwards on the manual we have, therefore, CC (double C), C (tenor C), c (middle C), c1 (treble C), c2 (C in alt) and c3 (C in altissimo). This is the highest note on the keyboard of 61 keys. According to the modern nomenclature of the pianoforte keyboard this note is c4, and is frequently so stated erroneously in organ specifications.
GG is four notes below CC, the break in the scale coming between GG and FFF. Tenor C is an important note to remember. Here is where the cheap builder came in again. He cut his stops short at tenor C, trusting to the pedal pipes to cover the deficiency.
PROSPER-ANTOINE MOITESSIER, INVENTOR OF TUBULAR PNEUMATIC ACTION
In the year 1845, Prosper-Antoine Moitessier, an organ-builder of Montpellier, France, patented what he called "abrégé pneumatique," an organ action in which all back-falls and rollers were replaced by tubes operated by exhaust air. In 1850 he built with this action an organ of 42 speaking stops for the church of Notre Dame de la Dalbade at Toulouse. This organ lasted 33 years. In 1866 Fermis, schoolmaster and village organist of Hanterire, near Toulouse, improved on Moitessier's action by combining tubes conveying compressed air with the Barker lever. An organ was built on this system for the Paris Exhibition of 1867, which came under the notice of Henry Willis, by which he was so struck that he was stimulated to experiment and develop his action, which culminated in the St. Paul's organ in 1872. (From article by Dr. Gabriel Bédart in Musical Opinion, London, July, 1908.)