100 



MUSIC. 



of the thickness, length, and lightness of the chords, 

 the quality, diameter, and distance of the openings 

 in wind instruments, and the like ; and all these 

 proportions can be determined and measured 

 according to mathematical rules. This regularity 

 may perhaps afford the reason why the effects of 

 music are so general, and its influence on the nerves 

 so powerful. The same circumstance renders it 

 incapable of expressing those fine shades of feeling 

 which can be communicated only by the aid of 

 reflection. 



When by any means the air surrounding the organ 

 of hearing is put into an undulatory or waving motion, 

 the drum vibrates, and these vibrations are, by the 

 beautifully contrived apparatus of the internal ear, 

 conveyed to the auditory nerve, and passing to the 

 brain, occasion the sensation of sound. These un- 

 dulations in the air will be followed by a perception 

 of sound, if they affect the drum of the ear, provided 

 they be not fewer than thirty-two, or more numerous 

 than 8192 in the second of time : and the distinguish- 

 ed characteristic of musical sound is, that the vibra- 

 tions which produce it are repeated at equal intervals, 

 that is, with the same rapidity for a sensible time ; 

 a circumstance which is expressed by saying, that 

 the sound keeps at the same pitch. Pitch and 

 strength are very different qualities of sound. The 

 pitch of a boy's voice is much higher than that of a 

 man's, or the pitch of a table bell than a church bell ; 

 but the strength of each of the latter generally 

 exceeds that of the former. The pitch of a sound 

 depends upon the number of vibrations that the 

 sounding body makes in a given time, the pitch being 

 the higher, the more numerous these vibrations are. 

 The strength of a sound, on the other hand, depends 

 on the largeness of the waves of air. The string of 

 a violin when touched with the bow will vibrate, and 

 if its length or tension be not altered, its vibrations 

 will all be at equal intervals from each other, and the 

 sound produced, remaining at the same pitch for a 

 sensible time, is musical. But if, whilst the string is 

 acted upon by the bow, the finger by sliding gradually, 

 shortens the string, the pitch of the sound will alter 

 continually, and the sound is no longer musical. The 

 sounds of the voice in speaking are, therefore, not 

 musical, for although a whole sentence be pronounc- 

 ed in what is called a monotone, still every syllable 

 is inflected in some degree, so that the pitch of the 

 voice in pronouncing the word and, is in no case the 

 same, at the beginning, middle, and end. If the 

 voice remain at the same pitch during the enuncia- 

 tion of a single syllable, that syllable is not spoken, 

 but sung. The most simple and convenient measure 

 of the pitch of a sound, is a string stretched over 

 two supports, as the string of a piano forte. The 

 string on being struck will vibrate and produce 

 sound, and the number of its vibrations in a given 

 time may be regulated by three circumstances. 

 The heavier a given portion of the string is, the less 

 tensely it is stretched, and the greater the distance 

 netween the supports, the fewer will be the number 

 of vibrations in a given time, and vice versa. For 

 the sake of simplicity we will suppose that the 

 weight of the string is unaltered, and that its ten- 

 sion remains unchanged, but that the distance be- 

 tween the supports can be increased or diminished at 

 pleasure. Let the string be struck, and let the tone 

 produced be called the key note, and let the length 



of the string, that is, the distance between the sup- 

 ports or bridges on which it is stretched, be measured 

 Let, now, one of the supports be moved, so that the 

 length of the string shall only be one half of what it 

 was before, and the string being made to sound, the 

 tone produced will be higher in pitch than the key 

 note, and will have that relation to it which musi- 

 cians call an octave. With the exception of the 

 relation of union or tones of the same pitch, no two 

 tones could bear any more simple relation to each 

 other than that of the key note and its octave. It is, 

 in fact, established by nature, for when the two tones 

 are sounded together, they almost entirely unite, and 

 they form the limits of the musical scale. Between 

 the key note and its octave there is a natural grada- 

 tion by intervals in the pitch of tone, more agreeable 

 than any other, the octave, as its name implies, being 

 the eighth, the whole forming a complete scale of 

 music, called the natural scale. The octave of the 

 key note may be the key note of a similar scale, 

 which will be a repetition of the first, but higher in 

 pitch : and the two scales, if sung together, will, to an 

 unpractised ear, appear to be identically the same. 

 The relation of the intervals, or differences of pitch 

 in the several tones of the natural scale, forms the 

 fundamental part of the study of music. Their value 

 may be determined correctly by taking the length 

 of the strings by which they are produced. If the 

 length of the string which produces the key note be 

 32 inches, the length of the strings to produce the 

 tones in the entire scale will be 



32, 30, 27, 24, 21, 20, 18, 16. 



The arrangement of the tones of the scale in suc- 

 cession, so as to give pleasure to the hearer, forms 

 that department of music called Melody ; but if the 

 sounds are combined, so that more than one shall be 

 heard at once, the arrangement comes under the 

 denomination of Harmony. 



In order to represent to the eye the different pitch 

 of the musical tones, five parallel lines are employed, 

 called a staff or stave, and the degree of pitch is 

 shown by certain characters placed upon these lines, 

 or on the spaces between them, the character having 

 a higher place on the stave which represents the tone 

 having a higher pitch 



These characters are called notes, and are of dif- 

 ferent forms; this, I however, is the only one which 

 we shall employ in the mean time, for the purpose of 

 marking the degree of pitch of the tones. It will be 

 seen in the stave represented above, that we have 

 placed a note on the space below the first line, and 

 another on the space above the fifth, and a note on 

 each space and line intervening, so that by this ar- 

 rangement we are enabled to represent the pitches 

 of eleven notes, being one entire octave and part of 

 another. But as one tune often comprehends tones 

 which differ from each other in pitch even more than 

 two octaves, an additional expedient is employed, 

 viz. lines called ledger or added lines, placed both 

 below and above the stave, so that we may represent 

 tones differing in pitch to the extent of three octaves, 

 thus : 



