TILE FORM OF TILE NOTES. As long as music had no distinctive rhythm of its own and the musical accents were determined only by the word-accent, Guido's system of using simple dots answered all purposes. But it was not long be fore the need of notes having a fixed time-value made itself felt. Franco of Cologne. in the twelfth century, replaced the clots by notes of various shapes to indicate their relative dura tion. lie also indicated the time-value of pauses or rests by a series of signs corresponding in duration to the different notes. A full account of this elaborate and difficult system will be found under MENSURABLE MUSIC. This system has become the foundation of our modern system of notation. The notes of larger value, the large, long, and brere, have disappeared. the nen/O-ere having become our standard of value or whole note. The development of instrumental music during the eighteenth century brought with it a great advance in the technique of the instru ments, and this led composers to write passages requiring more rapidity of execution than is possible to obtain from choral masses. Round notes were substituted for the square ones, be cause the former can be written more easily and rapidly. Another hnportant innovation, and one which greatly facilitated the reading of scores, was the joining of all notes having hooks into groups readily recognized by the eye. Thus a passage which formerly was written Whereas before his time only the spaces or the lines hail been used, Guido made use of both Whereas formerly the semifusa (corresponding to our sixteenth) was the note of smallest value, the increased rapidity rendered possible by in strumental technique led to a subdivision of six teenths into thirty-seconds, and of these latter even into sixty-fourths. The signs denoting the rests in mensurable music have been adopted into the modern system without modification.
TuE CLEFS. The oldest of the clefs is the F clef, which in its original form as a red line dates back to the tenth century. Almost as old is the C clef, which originally was a yellow line. These colored lines were used without a
clef signature. as it was understood that every note upon the red line represented F, and every note upon the yellow line C. Later on the colored lines disappeared, black ones being sub stituted and the letter F or C placed at the beginning. (Sec NEumEs.) The modern forms of these clefs are the result of a series of modifications of the plain letters.
The G clef is more recent than the other two, but its present form is the result of similar changes of the letter G.
Originally the different clefs had no fixed posi tion as they have to-day. In order to avoid the use of ledger-lines (which, in fact, were unknown), the position of the clefs was con stantly shifted, so as to bring the range of every voice within the limits of the stave. In old manuscripts we find every clef, at various times, on every line of the stave. Even within the same melody the clef changes frequently. This arbitrary use of the clefs continued until the seventeenth century. The establishment of opera (q.v.) brought with it the introduction of many new instruments. To bring the range of all these instruments within the limits of the stave could not be accomplished any longer by the trans position of clefs. Previously some polyphonic writers of the sixteenth century had on very rare occasions resorted to the use of a single ledger line above or below the stave. This idea was taken up by the operatic composers. and thus ledger-lines became a fixture in music. Now that there was no longer any need for the con stant transposition of clefs, the positions of those that remained in use became definitely fixed. Each voice-part had its own clef, as also the violin: In this form the classic masters have used the clefs. For the pianoforte the 0 and F clefs are used; the higher pitched orchestral instruments play with the G clef, those of lower pitch the F clef. The viola is the only one for which the alto clef (C) is retained. During the nineteenth cen tiny the C clefs have been superseded even in vocal music by the G clef.