by art and imitation; whereas brutes utter their voices without being taught, that is, by the instinct of their nature. Secondly, the voices of brutes are not separable into simple elementary sounds, as the speech of man is; nor do they admit of that amazing variety whereof our articulate voices are susceptible. And, thirdly, they seem to express, not separate thoughts or ideas, but such feelings, pleasant or painful, as it may be necessary, for the good of those animals, or for the benefit of man, that they should have the power of uttering.

25. We learn to speak, by imitating the speech of others; so that he who is born quite deaf, and continues so, must of necessity be dumb. Instances there have been of persons, who had heard in the beginning of life and afterwards became deaf, using a strange sort of language, made up partly of words they had learned, and partly of other words they had invented. Such persons could guess at the meaning of what was spoken to them in their own dialect, by looking the speaker in the face, and observing the lips, and those other parts of the face, which are put in motion by speaking.

26. We speak, in order to make our thoughts known to others. Now thoughts themselves are not visible, nor can they be perceived by any outward sense. If, therefore, I make my thoughts perceptible to another man, it must be by means

of signs, which he and I understand in the same sense. The signs that express human thought, so as to make it known to others, are of two sorts, natural and artificial.

27. The natural signs of thought are those outward appearances in the eyes, complexion, features, gesture, and voice, which accompany certain emotions of the mind, and which, being common to all men, are universally understood. For example, uplifted hands and eyes, with bended knees, are in every part of the world known to signify earnest entreaty; fiery eyes, wrinkled brows, quick motions, and loud voice, betoken anger; paleness and trembling are signs of fear, tears of sorrow, laughter of merriment, &c. Compared with the multitude of our thoughts, these natural signs are but few, and therefore insufficient for the purposes of speech. Hence artificial signs have been universally adopted, which derive their meaning from human contrivance, and are not understood except by those who have been taught the use of them.

28. These artificial signs may be divided into visible and audible. The former are used by dumb men; by ships that sail in company; and sometimes by people at land, who, by means of fire and other signals, communicate intelligence from one place to another: but for the ordinary purposes of life such contrivances would be inconvenient and insufficient. And therefore audible

signs, performed by the human voice, are in all nations used in order to communicate thought. For the human voice has an endless variety of expression, and is in all its varieties easily managed, and distinctly perceptible by the human ear, in darkness as well as in light.

29. Human voice is air sent out from the lungs, and by the windpipe conveyed through the aperture of the larynx, where the breath operates upon the membranous lips of that aperture, so as to produce distinct and audible sound; in a way resembling that in which the lips of the reed of a hautboy produce musical sound when one blows into them. We may indeed breathe strongly, without uttering what is called voice: and, in order to transform our breath into vocal sound, it seems necessary, that, by an act of our will, which long practice has rendered habitual, we should convey a sort of tenseness to the parts through which the breath passes. New-born infants do this instinctively; which changes their breathing, when stronger than usual, into crying. And persons in great pain do the same; which transforms their breathing into groans.

30. The aperture of the larynx is called the glottis, and, when we swallow food or drink, is covered with a lid called the epi-glottis. As our voice rises in its tone, the glottis becomes narrower, and wider as the voice becomes more grave or deep. Now any ordinary human voice may sound

a great variety of tones; and each variety of tone is occasioned by a variation in the diameter of the glottis. And therefore, the muscles and fibres, that minister to the motion of these parts, must be exceedingly minute and delicate.

31. One may use one's voice without articulation; as when one sings a tune without applying syllables to it: in which case the vocal organs perform no other part than that of a wind instrument of music. But speech is made up of articulate voices: and articulation is performed by those parts of the throat and mouth, which the voice passes through in its way from the larynx to the open air; namely, by the tongue, palate, throat, lips, and nostrils. Speech is articulated voice: whispering is articulated breath.

32. Of vocal articulated sounds the simplest are those which proceed through an open mouth, and which are called vowel sounds. In transmitting these, the opening of the mouth may be pretty large, or somewhat smaller, or very small; and thus three different vowel sounds may be formed, each of which may admit of three varieties, according as the voice, in its passage through the inside of the mouth, is acted upon by the lips, the tongue, or the throat. In this way, nine simple vowel sounds may be produced. There are ten in the English tongue, though we have not a vowel letter for each. Indeed our alphabet of vowels is very imperfect. In other languages there

may be vowel sounds different from any we have: that of the French u is one.

33. When the voice in its passage through the mouth is totally intercepted by the articulating organs coming together, or strongly compressed by their near approach to one another, there is formed another sort of articulation, which in writing is marked by a character called a consonant. Now silence is the effect of a total interception of the voice, and indistinctness of sound is produced by a strong compression of it. And therefore, a consonant can have no distinct sound, unless it be preceded or followed by a vowel, or opening of

the mouth.

34. The variety of consonants, formed by a total interception of the voice, may be thus accounted for. The voice, in its passage through the inside of the mouth, may be totally intercepted by the lips, or by the tongue and palate, or by the tongue and throat; and each of these interceptions may happen, when the voice is directed to go out by the mouth only, or by the nose only, or partly by the mouth and partly by the nose. In this way we form nine primitive consonants; which are divided into mutes, P, T, K; semimutes, B, D, and G, as sounded in egg; and semivowels, M, N, and that sound of NG which is heard in king, and which, though we mark it by two letters, is as simple a sound as any other. The mutes are so called, because their sound instantly and totally