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 tulerable 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 wnakeshift 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 Le employed as a substitute for the violin, and in such vicarious uses it is past all question one of the handiest of deputies.
mal note of the key.
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- cordiug 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, anda 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 eseape, 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 may be 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 rced compartments, shutting them off when closed. These compartments are of about two octaves and a half each, there being a division in 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 distance. The front hass and treble rows are the ‘‘ diapason ” of the pitch known as 8 feet, and the Lourdon (double diapason), 16 feet. These may be regarded as the foundation stops, and are technically the front organ. The back ergan has solo and combination stops, the principal of 4 feet (oetave higher than diapason), and bassoon (bass) aud 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 éolicnne,” two bass rews of 2 fect pitch, the one tuned a beat too sharp, the othera beat too flat, to produce a waving tremulous tone that hasa certain charm; ‘“ musette” and ‘ voix celeste,” 16 feet; and “baryton,” a treble stop 32 feet, or two octaves lower than the nor- The ‘‘ back organ” is usually covered ly a swell box, containing louvres or shutters similar to a Venetian blind, and divided into fortes corresponding with the bass and trelle division of the registers. The fortes are governed by knee pedals which act by pneumatic pressure, Tuning the reeds is ellected by seraping them at the point to sharpen them, or near the shoulder or heel to flatten them in pitch. Air pressure affeets the pitch but slightly, noticeable only in the larger reeds, and harmoniun:s 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 promptcr responsc to the depression of the key, or quicker specch ; 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 arc called upon hy 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 Jowest bass notes. The ‘‘ tremolo” affects the wind in the vicinity of the reeds by small bellows which in- creascs the pulsation in rapidity according to pressure; and the “sourdine” diminishes the supply of wind by contrelling its ad- mission to the reeds.
The American Organ, as already said, acts by wind exhausticn. A vacuumn 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 exaetly 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 elose 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 easicr, ladies find it much less fatiguing. To these differences we may attribute its increasing popularity. The expression step 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 pro- duce a tremulous effect, not unlike the beatings heard from com- bined voices, whence 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 ”’—diflerent makers occasionally vary the use of fancy names for other stops. The ‘‘ subbass,” however, an oetave of 16 feet pitch and always apart from the other reeds, ts uscd 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 feet, the lowest note being then CC. Blowing for pedal instruments has to be done by hand a
