INSTRUCTION LIV.

TONE.

Think again of the sounds of the harp-strings. Think again of the sounds of Duncan's voice. They seemed to be long sounds. They seemed to be made up of many; but all flowing into each other, and making one smooth sound, called a tone.

A tone is a musical sound, produced by regular tremblings in the sounding body. If a toothed wheel turns slowly, and its teeth strike against a piece of a quill, or thin steel, as a watch-spring, we hear a sound produced by each tooth. If it turns swiftly, the ear cannot notice the stroke of each tooth. They flow into each other, and we hear a smooth, continuous sound, called tone.

Did

Have you looked at the strings of Duncan's harp you notice that some of them were thick, and some were thin: : some were long, and some were short? Now, when he touches the long thick strings, they vibrate or tremble slowly. We hear a grave tone. When he touches the short thin strings, they tremble quickly. We hear a sharp sound

or tone.

A grave tone is one produced by slow tremblings of a sounding body. There are few in a given time, as a minute.

A sharp tone is one produced by quick tremblings of a sounding body. There are many in a given time.

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INSTRUCTION LV.

THE ORGAN OF VOICE.

Voice, we have seen, is living sound. But sound is produced by the tremblings of a sounding body. The wind, the stroke of a hammer or a musical string will produce it. Voice must be produced in a way somewhat like this. It is made by the organ of voice. This is a wonderful instrument. We know this in speech and song. No flute, or harp, or organ can equal it.

The organ of voice is composed of many parts. These are the lips, teeth, palate, nose, tongue, throat, epiglottis, larynx, glottis, lips of the glottis, windpipe, bronchia, and lungs.

THE LIPS.

The lips are the borders of the mouth. They are useful in forming voice. We see them move in speech and song. We feel them acting in sounding O, or U, or BABE.

THE TEETH.

The teeth are the walls of the mouth. They are thirty-two in number, and do something in forming voice. They break it, and give it a new form. We feel this in saying HUSH, or ZONE: we feel it in pronouncing z, or s.

THE PALATE.

The palate is the roof of the mouth. It gives roundness and fulness to the voice. We feel this in saying lull, ROAM, or RILL: we feel it in pronouncing L, N, or R.

THE NOSE.

The nose opens into the palate by two openings, called nares. These give a resounding quality to the voice. They give it a bell-like ringing sound. We are aware of this in saying the words, INK, and RING: we feel it in pronouncing N, NG.

THE TONGUE.

The tongue is an organ of the mouth, and very active in forming voice. It is connected with almost every sound which we make. We feel its action in sounding D, or B; or saying the words DEAD, and TENT.

THE THROAT.

The throat is the fore part of the neck, and opens into the windpipe. The voice comes from there. The lips, teeth, palate, nose, and tongue only change it. We feel that this is so in sounding AH, or HAH.

THE EPIGLOTTIS.

The epiglottis is a thin membrane or skin that shuts as a lid upon the opening into the windpipe. It closes this opening when we swallow. It helps to change the voice. Its form is like the leaf of a flower, somewhat oval. See the picture of the glottis, and the lips of the glottis.

THE LARYNX.

The larynx is the upper part of the windpipe. It is a hollow tube like a cone. It is called so, because it resembles

a whistle somewhat, like the willow ones made by boys. The sound comes out of the larynx. Its hollowness makes the voice resound like the hollowness of a violin. The following picture is a side view of it. The epiglottis appears as a lid.

THE GLOTTIS AND THE LIPS OF THE GLOTTIS.

The glottis is an opening within the larynx, like a slit. The voice is formed in this opening, as sound is formed in the mouth of a clarionet. The lips of the glottis. are thin membranes that lie along the borders of the glottis. These tremble as the air passes out from the lungs; and form or change the voice. Thus two kinds of instruments are united in the human voice, the wind and the stringed instrument.

THE WINDPIPE.

The windpipe is a tube of rings. It extends from the larynx to the bronchi. It can be shortened or lengthened, and thus change the quality of the voice, as the length of a flute or organ-pipe changes sound.

THE BRONCHI.

The bronchi are two branches of the windpipe, connecting it with the lungs. They enter the lungs, and divide again and again, till they end in small air-cells. These, if spread out, would cover 20,000 square inches. They conduct the air from the lungs to the windpipe. See the picture of the lungs.

THE LUNGS.

The lungs are two large lobes of air-cells, connected with the bronchi and the heart. They supply the air which is used in forming voice, as the bellows of the organ supply it to the pipes of the organ.