The degrees of strength, the loudness or the softness of voices, have no effect whatever on the pitch or relative tone ; for we may whisper in bass, and bawl in soprano. Therefore, when we say high or low, we either put the intonation to some audible test, as by reference to the sounds of instruments, &c. whose exact pitch is previously ascertained ; or, in our minds, we form an estimation by aid of the me mory, which refers to the graveness or acuteness, as it may happen, of some in strument, with whose notes the voice in question seems to correspond. Thus high and low are positive definitions, which force, or the accumulation of strength, as in choruses, will not render shriller or more acute, nor softness and whispering render more deep or graver. The terms are, however, only to be con sidered as arbitrary ; for they have no real foundation in regard to the nature of sounds, and seem to depend entirely on the manner in which music is written, the shriller tones being placed the highest on the stave of five lines, and the deepest tones being represented by the lowest notes; thus forming a gradual decrease of acuteness from the highest to the low est,w hich declension being, by this means, represented to the eye, enables us to judge, without hesitation, as to the pitch of the several intonations thus represent ed. By this means we are able to com pare the pitch of two voices, or of any number of instruments whereby they might be accompanied ; for by inspecting the music as written on the stave, and ob serving the relative ascendance of the notes, as allotted to, or as they could be executed by, each singer, we at once de cide, that the person performing those fates, which reach the highest on the stave, sings higher than the other ; there. fore, if they should sing in parts,we should say the highest singer df the two took the first, and the lowest singer the second part of the music. The ancient Greeks used the terms high and low, in an oppo site sense to what is above descrihed. The lyres in use among them were so varied, that their gravest sounds were produced from the uppermost strings, and viee versa ; hence they called the deepest notes high, and the neuter notes low.
It is not to be supposed that all the sounds which can, by any means, be pro duced, should be represented on the five lines, called the stave, although we never see more lines ruled for that purpose the whole length of the stave. There are ma ny notes carried far above, and far below : their relative sounds are distinguished by what are called ledger (properly legere, or light) lines, the number of which serve to shew the degrees of altitude or of de pression respectively. But it must be ob vious how ineffectual even this substantial aid would be, to specifyall the intonations contained in the six species already no ticed. It is true, the upper, or soprano species, admits of much explanation, by the addition of perhaps four or five ledger lines above the stave ; but the great num ber of sounds below the stave would re. quire such a number of ledger lines under it, as would inevitably create confusion, and render it impossible for the most quick sighted and most practised per. former to follow the melody with preci sion. To remedy this inconvenience, and to do away many other practices, which, though improvements on the modes of the earlier ages, were not only very defective, but seemed to debar the progress of this pleasing science, the celebrated John de Murk), who lived in the fourteenth cen tury, offered to the world a new system (from which very few alterations have since been made), whereby not only the value, 1. e. the proper duration or holding of each note, was clearly defined by cer tain marks, but the compass, or extent of each voice, or part, was distinctly laid down by appropriate clefs, or keys, which are now vulgarly called cliffs. Until that
time the pitch and value of every note were known only by letters and signs used for the occasion, according to Gui do's notation.
This change was peculiarly important, and received additional approbation from its great simplicityt ; by it the whole or chestra were divided into three great classes, namely, the trebles, the tenors, and the basses; while, at the same time, the voice parts were more methodically arranged into five parts, consisting of two trebles (1. e. first and second), two tenors, and one bass, forming what we call a quintett ; but in general only four were used, namely, the soprano, the counter tenor, the tenor, and the bass ; and, in deed, such seems, on the whole, to be the most natural division, for as we rarely find more than four notes used in any chord that is sounded at the same mo ment, so it appears proper that the num ber of parts, vocals at least, should be comprised within that arrangement; few er would often cause the omission of ma ny notes, whereon the harmony might es sentially depend. The propriety of this will be more evident, when we come to treat of discords.
In speaking of parts, we are not to con clude that music is now confined to any particular number, although four, or five at the furthest, are as many as can be ge nerally found useful, or even applicable to the purposes of our most conspicuous exhibitions, such as operas, oratorios, &c. Various eminent composers have arrang ed their pieces for even as many as fifteen or sixteen voices, each independent, and not merely the repetition or echo of others ; these are called real parts, in con tradistinction to such as are similar to others, but being performed on different instruments, or being an octave higher or lower, become mere reinforcements. Thus when we see an orchestra of forty or fifty performers, we are not to conclude that each performs a succession of notes different from his neighbours ; on the contrary, all,who play the first violin parts, play exactly the same passages through out; the seconds have also their part of the composition, which they play together ; the tenors, first and second, sometimes in the same manner ; the basses are also of variousdescriptions, such as the violincel los and the double basses. The wind in struments, such as the horns, trumpets, trombones, flutes, oboes, clarinets, the bassoons, and the serpents, are also class ed, though each in general has its sepa rate part, which, when sustaining any full passage, blends freely with the others of its own class, rarely deviating much there from, except in solo passages, wherein peculiar effects are to be produced. It may be supposed that most of these parts must be duplicates of others, either throughout, or partially, when we consis der that the performer at the organ or harpsichord plays all the harmony, con centered, as it were, under his own hand. Knowing this, we must view the forma tion of numerous vocal parts merely as an exercise in the arts of permutation, as we see the youths of various parishes emulating in the ringing of various peals on the bells ; or we must judge, that in instrumental music the various parts are necessary to produce a superior effect, derived from the judicious appropriation of various passages, or of various empha tic and accented notes, to those instru ments most suited to the desired expres sion. We shall not beat a loss to esti mate this branch of the science duly, when we call to mind, that by such a con trivance, which is by no means superfi cial, some composers have so completely expressed the passions of love, hatred, fear, grief, joy, &c. as to cause ;heir au diences to become deeply affected, ac cording to the intention and character of the music.