A Dictionary of Music and Musicians/American Organ
AMERICAN ORGAN. A free-reed instrument similar in its general construction to the Harmonium, but with some important differences. In the first place the reeds in the American organ are considerably smaller and more curved and twisted than in the harmonium, and there is a wider space left at the side of the reed for it to vibrate, the result being that the tone is more uniform in power, and that the expression stop when used produces much less effect. The curvature of the reeds also makes the tone softer. In the American organ moreover the wind-channel or cavity under which the vibrators are fixed is always the exact length of the reed, whereas in the harmonium it is varied according to the quality of tone required, being shorter for a more reedy tone and longer for a more fluty one. Another point of difference in the two instruments is that in the harmonium the wind is forced outward through the reeds, whereas in the American organ, by reversing the action of the bellows, it is drawn inwards. The advantages of the American organ as compared with the harmonium are that the blowing is easier, the expression stop not being generally used, and that the tone is of a more organ-like quality, and therefore peculiarly adapted for sacred music; on the other hand, it is inferior in having much less variety of tone, and not nearly so much power of expression. These instruments are sometimes made with two manuals; in the most complete specimens the upper manual is usually furnished with one set of reeds of eight-feet and one of four-feet pitch, and the lower manual with one of eight- and one of sixteen-feet, those on the upper manual being also voiced softer for the purposes of accompaniment. A mechanical coupling action is also provided by which the whole power of the instrument can be obtained from the lower row of keys. Pedals, similar to organ pedals, are also occasionally added and provided with reeds of sixteen- and eight-feet pitch. The names given to the stops vary with different makers; the plan most usually adopted being to call them by the names of the organ stops which they are intended to imitate, e. g. diapason, principal, hautboy, gamba, flute, etc. Two recent improvements in the American organ should be mentioned the automatic swell, and the vox humana. The former consists of a pneumatic lever which gradually opens shutters placed above the reeds, the lever being set in motion by the pressure of wind from the bellows. The greater the pressure, the wider the shutters open, and when the pressure is decreased they close again by their own weight. In this way an effect is produced somewhat similar, though far inferior, to that of the expression stop on the harmonium. The vox humana is another mechanical contrivance. In this a fan is placed just behind the sound-board of the instrument, and being made to revolve rapidly by means of the pressure of wind, its revolutions meet the waves of sound coming from the reeds, and impart to thdm a slightly tremulous, or vibrating quality.
The principle of the American organ was first discovered about 1835 by a workman in the factory of M. Alexandre, the most celebrated harmonium-maker of Paris. M. Alexandre constructed a few instruments on this plan, but being dissatisfied with them because of their want of expressive power, he soon ceased to make them. The workman subsequently went to America, carrying his invention with him. The instruments first made in America were known as 'Melodeons,' or 'Melodiums,' and the American organ under its present name, and with various improvements suggested by experience, was first introduced by Messrs. Mason and Hamlin of Boston, about the year 1860. Since that time it has obtained considerable popularity both in America and in this country.
A variety of the American organ was introduced in 1874 by Messrs. Alexandre under the name of the 'Alexandre Organ.' In this instrument, instead of the single channel placed above the reeds there are two, one opening out of the other. The effect of this alteration is to give a quality of tone more nearly resembling that of the Sue-stops of an organ. The reeds are also broader and thicker, giving a fuller tone, and being less liable to get out of order.