HARMONIUM. Perhaps no musical instrument ever became in a few years so widely known and used as the harmonium. The reasons for this may at once be found in the facilities it offers for playing easy music, and, when simply constructed, its comparatively low price, which renders the purchase of a tolerable harmonium possible when the cheapest pianoforte fairly playable would be un-attainable, and the real organ, although of chamber size, quite out of the question. Besides being a convenient makeshift for an organ, the harmonium can also be used in domestic concerted music, to play all or any of the wind band parts of the orchestra; it may even be employed as a substitute for the violin, and in such vicarious uses it is past all question one of the handiest of deputies.
It is true the tone of the harmonium is not in itself beautiful; the prominence in sounds from reeds of certain overtones is irreconcilable with pleasure to the ear unless by convention of habit, and the necessity of tuning ac-cording to equal temperament all major thirds too sharp leads through this harmonic peculiarity in the chords to an abnormally disagreeable quality, from which those whose nerves are very sensitive or weak are not unfre-quently painfully affected. The American organ, a kind of harmonium of late years much in vogue, owes its popularity to its being less pronounced and reedy in timbre (its softer tone being nearer to that we are familiar with in the church organ), and to its being easier to play for simple domestic use. Yet the real harmonium has more in-dependent character as an instrument, and is capable of higher treatment in performance than the American organ.
Both are known as "free-reed " instruments, the musical tones being produced by tongues of brass, technically "vibrators," set in oblong frames; the sides of these they do not quite touch, but pass, when in movement, freely downwards,the " beating reeds " used in church organs covering the entire orifice. A reed or vibrator, set in periodic motion by impact of a current of air, produces a corresponding succession of air puffs, the rapidity of which determines the pitch of the musical note. There is an essential difference between the harmonium and the American organ in the direction of this current; in the former the wind apparatus forces the current upwards, and in the latter sucks it downwards, whence it becomes desirable to separate in description these varieties of free-reed instruments.
The Harmonium, has a keyboard of five octaves compass when complete, from C to C, and a simple action controlling the valves, &c. The necessary pressure of wind is generated by bellows worked by the feet of the performer upon footboards or treadles. The air is thus forced up the wind-trunks into an air-chamber called the wind-chest, the pressure of it being equalized by a reservoir, which receives the excess of wind through an aperture, and permits escape, when above a certain pressure, by a discharge valve or pallet. The aperture admitting air to the reservoir may be closed by a drawstop named "expression." The character of the instrument is then entirely changed from a mechanical response to the player's touch to an expressive one, rendering what emotion maybe communicated from the player by increase or diminution of sound through the greater or less pressure of wind the reeds may be submitted to. The draw-stops bearing the names of the different registers in imitation of the organ, admit, when drawn, the wind from the wind-chest to the corresponding reed compartments, shutting them off when closed. These compartments are of about two octaves and a half each, there being a division iu the middle of the keyboard scale dividing the stops into bass and treble. A stop being drawn and a key pressed down wind is admitted by a corresponding valve to a reed or vibrator. Above each reed in the so-called sound-board or pan is a channel, a small air-chamber or cavity, the shape and capacity of which have greatly to do with the colour of tone of the note it reinforces. The air in this resonator is highly compressed at an even or a varying pressure as the expression-stop may not be or may be drawn. The wind finally escapes by a small pallet-hole opened by pressing down the corresponding key. In Mustel and other good harmoniums, the reed compartments that form the scheme of the instrument are eight in number, four bass and four treble, of three different pitches of octave and double octave dis-tance. The front bass and treble rows are the "diapason" of the pitch known as 8 feet, and the bourdon (double diapason), 16 feet. These may be regarded as the foundation stops, and are technically the front organ. The back organ has solo and combination stops, the principal of 4 feet (octave higher than diapason), and bassoon (bass) and oboe (treble), 8 feet. These may be mechanically com-bined by a stop called full organ. M. Mustel, the French maker, whose pre-eminence is universally acknowledged, has added other registers for much admired effects of tone, viz.," harpe eolienne," two bass rows of 2 feet pitch, the one tuned a beat too sharp, the other a beat too fiat, to produce a waving tremulous tone that has a certain charm; "musette" and " voix celeste," 16 feet; and " baryton," a treble stop 32 feet, or two octaves lower than the nor-mal note of the key. The '' back organ " is usually covered by a swell box, containing louvres or shutters similar to a Venetian blind, and divided into fortes corresponding with the bass and treble division of the registers. The fortes are governed by knee pedals wdiich act by pneumatic pressure. Tuning the reeds is effected by scraping them at the point to sharpen them, or near the shoulder or heel to flatten them in pitch. Air pressure affects the pitch but slightly, noticeable only in the larger reeds, and harmoniums long retain their tuning, a decided advantage over the organ and the pianoforte. Mechanical contrivances in the harmonium, of frequent or occasional employment, besides those already referred to, are the " percussion," a small pianoforte action of hammer and escapement which, acting upon the reeds of the diapason rows at the moment air is admitted to them, gives prompter response to the depression of the key, or quicker speech ; the " double expres-sion," a pneumatic balance in the wind reservoir of great delicacy exactly maintaining by gradation equal pressure of the wind ; and the "double touch," by which the back organ registers speak sooner than those of the front that are called upon by deeper pressure of the key, thus allow prominence or accentuation of certain parts by an expert performer. " Prolongement" permits selected notes to be sustained after the fingers have quitted their keys. Dawes's " melody attachment" is to give prominence to an air or treble part by shutting off in certain registers all notes below it. This notion has been adapted by inversion to a " pedal substi-tute " to strengthen the lowest bass notes. The " tremolo" affects the wind in the vicinity of the reeds by small bellows which in-creases the pulsation in rapidity according to pressure; and the "sourdine" diminishes the supply of wind by controlling its ad-mission to the reeds.
The American Organ, as already said, acts by wind exhaustion. A vacuum is practically created in the air-chamber by the exhaust-ing power of the footboards, and a current of air thus drawn down-wards passes through any reeds that are left open, setting them in vibration. This instrument has therefore exhaust instead of force bellows. Valves in the board above the air-chamber give com-munication to reeds, made more slender than those of the har-monium and more or less bent, while the frames in which they are fixed are also differently shaped, being hollowed rather in spoon fashion. The channels, the resonators above the reeds, are not varied in size or shape as in the harmonium; they exactly corre-spond with the reeds, and are collectively known as the " tube-board." The swell " fortes " are in front of the openings of these tubes, rails that open or close by the action of the knees upon what may be called knee pedals. The tone of the American organ is softer than that of the harmonium; this is sometimes aided by the use of extra resonators, as, for instance, in Clough and "Warren's latest instruments (of Detroit, Michigan, U.S.), which they call pipes or qualifying tubes. The blowing being also easier, ladies find it much less fatiguing. To these differences we may attribute its increasing popularity. The expression stop can have little power in the American organ, and is generally absent; the "au-tomatic swell " in the instruments of Mason and Hamlin (of Boston, U.S.) is a contrivance that comes the nearest to it, though far in-ferior. By it a swell shutter or rail is kept in constant movement, proportioned to the force of the air-current. Another very clever improvement introduced by these makers, who are the originators of the instrument itself, is the "vox humana," a smaller rail or fan, made to revolve rapidly by wind pressure; its rotation, disturbing the air near the reeds, causes interferences of vibration that jiro-duce a tremulous effect, not unlike the beatings heard from com-bined voices, w hence the name. This vibrato stop has found general adoption. The arrangement of reed compartments in American organs does not essentially differ from that of harmoniums; but there are often two keyboards, and then the solo and combination stops are found on the upper manual. The diapason treble register is known as " melodia "different makers occasionally vary the use of fancy names for other stops. The " subbass," however, an octave of 16 feet pitch aud always apart from the other reeds, is used with great advantage for pedal effects on the manual, the compass of American organs being usually down to F (FF, 5 octaves). In large instruments there are sometimes foot pedals as in an organ, with their own reed boxes of 8 and 16 fcet, the lowest note being then CC. Blowing for pedal instruments has to be done by hand a lever being attached lor that purpose. The '1 celeste " stop is managed as in the harmonium, by rows of reeds tuned not quite in unison, or by a shade valve that alters the air-current aud flattens one row of reeds thereby.
Harmoniums and American organs are the results of many experiments to play upon free reeds by a key-board, initiated by the " orgue expressif" of Grenie, a Frenchman. During nearly the first half of this century various tentative efforts in France aud Germany, and subse-quently in England, came to nothing more valuable than the Viennese " physharmonica" of Hackel, the Parisian "melophone," and our own "seraphine." The inventor of the harmonium was indubitably Alexandre Debain, who took out a patent for it in Paris in 1840. He produced varied timbre registers by modifying reed chan-nels, and brought these registers on to one keyboard. Unfortunately he patented too much, for he secured even the name harmonium, obliging contemporary and future experimenters to shelter their improvements under other names, and the venerable name of organ becoming im-pressed into connexion with an inferior instrument, we have now to distinguish between reed and pipe organs. The compromise of reed organ for the harmonium class of instruments must therefore be accepted. Debain's harmonium was at first quite mechanical; it gained ex-pression by the expression-stop already described. The Alexandres, well-known French makers, by the ingenuity of one of their workmen, Martin, added the percussion and the prolongement. The melody attachment was the invention of an English engineer; the introduction of the double touch, now used in the harmoniums of Mustel, Bauer, and othersalso in American organsis due to Mr Tamplin, an English professor. Reference has already been made to the improvements of M. Mustel, a maker imbued with true artistic devotion.
The principle of the American organ originated with the Alexandres, whose earliest experiments are said to have been made with the view of constructing an instrument to ex- haust air. The realization of the idea proving to be more in consonance with the genius of the American people, to whom what we may call the devotional tone of the instru- ment appealed, the introduction of it by Messrs Mason and Hamlin in 1S61 was followed by remarkable success. They made it generally known in Europe by exhibiting it at Paris in 1867, and from that time instruments have been exported in large numbers by different makers. Har- moniums are not entirely, although chiefly, of French make. Mr Bauer, one of the best English makers, learned the trade in Paris, and employs chiefly French workmen. As keyed instruments, reed organs of either principle cannot be expected to compete musically with the older organ and pianoforte, yet the harmonium, studied for itself with something like the devotion that is given to the other keyed instruments, might be made more important than it is at present. Excepting from a few isolated students who may be told upon the fingers, it has received no true cultivation. Whether it will ever get this is a ques- tion that remains to be answered. Commercially the har- monium and American organ have taken a much more important place, although of course one not equal to that of the pianoforte. For some years the Alexandres were sending annually 7000 harmoniums to England. This afterwards, from various causes, diminished; the number, however, of their instruments made up to 1879 has reached 110,000. A general estimate of harmoniums made annually in France, Germany, and England is not forthcoming; but the yearly production of American organs in the United States has been stated at the large total of 40,000. (A. J. H.)