THEORY OF MUSIC.t 66. Moslem, sounds are arranged in order, as they be come gradually more and more acute in the scale, which is usually sung to the syllables do, re, mi, fa, sol, si ; or which is denoted by the letters C, D, E, F, G, A, B. This scale is heard when the long or white finger-keys of the piano forte are struck successively, beginning with C, and proceeding towards the right hand. The scale is so called from the Latin or Italian word scala, which signifies a lad der or stairs. When front the gravest or lowest sound we proceed to the higher or sharper sounds in their order, we are said to go up, or to ascend the scale; and when we pro ceed in the contrary direction, we are said to go down, or to descend the settle.
67. The steps, or degrees of this ladder, or scale, are not all equal. The first step, from C to D, is called a tone; the next step, from D to E, is similar, and is also called a tone; but the third step, from E to F, is immediately per ceived by the ear to be of a different kind. F is much less removed in height or sharpness, from E, than E is from D, or D from C. The step from E to F is called a semitone. The three next degrees from F to G, from G to A, and from A to B, are all tones. If We WISII to extend the scale still higher, the ear peremptorily requires that the next step front B to an eight sound should be a semitone; ancl we feel that this eight sound is necessary to make the ascending scale completely satisfactory to the ear.
When we compare this eighth sound with C, the lowest sound of the scale, we are immediately sensible that ihe two sounds have a very great resemblance to each other; and if the two sounds be struck at the same time, we feel that they almost entirely unite in the ear. The relation of these two sounds is indeed so intimate, that they are considered as re plications or repetitions of each other; insomuch that they have both the same name C. The higher note is called an eighth, or octave, above the lower, as this is called an oc tave below the higher.A.
68. Should we octaves above all the other sounds, D, E, F, G, A, B, we should have another scale of sounds proceeding from the second C, exactly similar to the former in all its steps, and denoted by the same letters or names, c, d, e, f, g, a, b. In order to show how truly these two octaves or scales, are repetitions of each other, let a male and a female voice sing the scale together; those who have never before attended to the observation, will believe that the iWO Noices are singing the same sounds; but, on a careful attention, it will be found that the female voice is all along singing octaves above the male voice. In like manner, should we iake octaves below all the sounds of the first scale, we should have a third scale exactly similar to the two former in all the degrees; and so the scale, or scales, may be carried as far upwards or downwards as may be required. Keyed instruments generally comprehend five or six oc taves.
69. This scale, in which the octave is divided into tones and semitones, as its elements, or smallest parts, is such as is furnished by keyed instruments in general. It is proper, however, to observe, that it is imperfect and defective. When the series of sounds is taken exactly as the ear desires them to be, other distinctions are found among them; with these, how evel „ we will not perplex the student at present, reserving an account of this matter to the sequel.
70. This simplest scale, consisting chiefly of degrees of a tone is called the diatonic scale, to distinguish it from other scales, in which the octave is divided into other elements, with which we shall afterwards get acquainted, It has also the epithet major, to distinguish it front another scale, called the minor diatonic scale—which distinction will be explained bye and bye.
71. Whether the analogy which we conceive between the relative qualities of sound, which we denote by the words grave and acute, and the relative qualities of' space, which we denote by the words low and high, be really founded in nature, or whether it be merely imaginary, and familiar to us by habit, we shall not stop to inquire ; but on this ana logy musical language and notation proceed. Five lines ruled at small intermediate distances, are called the staff. The lines and spaces represent the degrees of the scale, and furnish a convenient method of denoting, by marks or notes placed on them, the relative height and depth, that is, the acuteness and gravity of the sounds. The lines and spaces of the staff' are numbered from the lowest in the page up wards, and are called (Ile 1st, 2d, 3d, 4t11, and hth lines, the 1st, 2d, 3d, and 4th spaces. If Ave agree to put the mark or note of G on the second line of the staff, the scale will be written thus— extending through three octaves. This character at the beginning of the staff, represents the letter G, and it signifies tliat the note G is placed on the second line; and as this de termines the place of all the other notes, the character at the beginning of the staff is called the G clef, from the French word signifying a key, because it explains this notation. Ascending the scale, from G on the 2d line, A will be on the 2d space, B on the 3t1 line, C on the third space, and so on; descending from G, F will be on the 1st space, E on the 1st line, D below the staff, and C (octave below that on the 3d space) on a short line called a ledger-line, or added line. This C, on the ledger-line below the staff in the G elef, is that about the middle of the key-board of the piano-forte, and is called middle C. Thus the exact pitch of the sounds expressed in this notation is determined. De scending from this middle C, B will be under one ledger line, A Ona second ledger-line, aud G will be below two ledger-lines. In like manner the higher octaves are written with ledger-lines above the staff. But as it is difficult for the eye to catch the number of the ledger-lines and spaces when they are many, it is usual to write the highest notes of the scale as in the immediately lower octave, and to signify the true sounds luy Svo, with a dotted line running along the passage, t hus— The Italian word /oco is put after such a passage, to signify that the succeeding passage is to be read in its own place in the scale, as written. The G under two ledger-lines below the staff, is the lowest sound of the violin; and music for that instrument, for the flute, oboe, and other instruments whose scale extends no farther downwards, is written on the G clef; as is also in this country, the right hand part for keyed instruments, and vocal music for female or treble voices. This is also frequently called the treble clef; and the tipper part of the scale is called the treble.