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Such is the plan of the organ of hearing, as an architect might describe it. But the details of its special furnishing are so intricate and minute that no anatomist has proved equal to their entire and exhaustive delineation. A titled observer, the Marquis Corti, has hitherto proved most successful in describing the wonderful key-board found in the spiral chamber, the complex and symmetrical beauty of which is absolutely astonishing to those who study it by the aid of the microscope. The figure annexed shows a small portion of this extraordinary structure. It is from Kölliker's well-known work on Microscopic Anatomy.

[graphic]

Enough has been said to show that the ear is as carefully adjusted to respond to the blended

impressions of sound as the eye to receive the mingled rays of light; and that as the telescope presupposes the lens and the retina, so the organ presupposes the resonant membranes, the labyrinthine chambers, and the delicately suspended or exquisitely spread-out nervous filaments of that other organ, whose builder is the Architect of the universe, and the Master of all its harmonies.

Not less an object of wonder is that curious piece of mechanism, the most perfect, within its limited range of powers, of all musical instruments, the organ of the human voice. It is the highest triumph of our artificial contrivances to reach a tone like that of a singer, and among a hundred organ-stops none excites such admiration as the vox humana; a brief account of the Vocal organ will not, therefore, be out of place.

The principles of the action of the larynx are

easily illustrated by reference to the simpler musical instruments. In a flute or flageolet the musical sound is produced by the vibration of a column of air contained in its interior. In a clarinet or a bassoon another source of sound

is added in the form of a thin slip of wood contained in the mouth-piece, and called the reed, the vibrations of which give a superadded nasal thrill to the resonance of the column of air.

The human organ of voice is like the clarinet and the bassoon. The windpipe is the tube containing the column of air. The larynx is the mouth-piece containing the reed. But the reed is double, consisting of two very thin membranous edges, which are made tense or relaxed, and have the interval between them, through which the air rushes, narrowed or widened by the instinctive, automatic action of a set of little muscles. The vibration of these membranous edges (chorda vocales) produces a musical sound, just as the vibration of the edge of a finger-bowl produces one when a wet finger is passed round it. The cavities of the nostrils, and their side-chambers, with their light, elastic sounding-boards of thin bone, are essential to the richness of the tone, as all singers find out when those passages are obstructed by a cold in the head.

The human voice, perfect as it may be in

tone, is yet always very deficient in compass, as is obvious from the fact that the bass voice, the barytone, the contralto, and the soprano have all different registers, and are all required to produce a complete vocal harmony. If we could make organ-pipes with movable, self-regulating lips, with self-shortening and self-lengthening tubes, so that each tube should command the two or three octaves of the human voice, a very limited number of them would be required. But as each tube has but a single note, we understand why we have those immense clusters of hollow columns. As we wish to produce different effects, sometimes using the pure flutesounds, at other times preferring the nasal thrill of the reed-instruments, we see why some of the tubes have simple mouths and others are furnished with vibratory tongues. And, lastly, we can easily understand that the great interior spaces of the organ must of themselves furnish those resonant surfaces which we saw provided for, on a small scale, in the nasal passages,the sounding-board of the human larynx.

The great organ of the Music Hall is a choir of nearly six thousand vocal throats. Its largest windpipes are thirty-two feet in length, and a man can crawl through them. Its finest tubes are too small for a baby's whistle. Eighty-nine stops produce the various changes and combinations of which its immense orchestra is capable, from the purest solo of a singing nun to the loudest chorus in which all its groups of voices have their part in the full flow of its harmonies. Like all instruments of its class, it contains several distinct systems of pipes, commonly spoken of as separate organs, and capable of being played alone or in connection with each other. Four manuals, or hand key-boards, and two pedals, or foot key-boards, command these several systems, the solo organ, the choir organ, the swell organ, and the great organ, and the piano and forte pedal-organ. Twelve pairs of bellows, which it is intended to move by waterpower, derived from the Cochituate reservoirs, furnish the breath which pours itself forth in music. Those beautiful effects, for which the organ is incomparable, the crescendo and dimin

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