Page:Philosophical Review Volume 1.djvu/179

No. 2.] this scale and their octaves, within one or other of which all ecclesiastical melodies were restricted. This fundamental interval order of mediæval music was at the time of Guido d' Arezzo (eleventh century) extended by the addition of a note (Sol) below the lowest La, and of notes Si, Do, Re, Mi, above the highest; giving the following sequence of tones and hemitones:

In order to facilitate the memorizing of this scale, its twenty notes (the intermediate note being counted with Si) were associated with the tips and joints of the thumb and fingers of the left hand, proceeding downward from the tip of the thumb as Sol, and then upward on each of the fingers, the twentieth note, Mi, being conceived to float in the air, over the tip of the middle finger. This mnemonic device was called the Guidonian hand, and is mentioned here only to call attention to a like use of the joints and tips of the fingers among the Chinese, who associated the root of the ring finger with Huang-chung, that of the middle and first fingers with the second and third Lu, and successive adjacent joints and finger tips with the others, the twelfth Lu falling on the root of the little finger. (Amiot, p. 127, and Plate XVII.)

From the beginning of the tenth century the notes of this interval order were designated by the letters of the Latin alphabet, the lowest note being called A, and the successive higher ones B, C, etc., notes at octaves receiving the same name. The intermediate note of the higher octave (corresponding to the flatted pien-Tche of the Chinese scale, and a survival, as we know, from the Greek tetrachord synnemenon) came, therefore, to fall between A and B. To designate it, B was again used, the two B's being distinguished by writing the lower one round, b (B rotundus), and the upper one square, B (B quadratus). In the development of the art during the later middle ages and in Reformation times, further notes intermediate to those of the old Greek order came into use. But the authority of classic and Catholic tradition was such that these were at first supplied by the singers without being written (Musica Ficta or Falsa); and when later it became the habitude to express them in notation, they were looked upon as derived either from the diatonic note above by a displacement like that which would produce b from B, or from the diatonic note below by a displacement which would produce B from b, and were designated by affixing to the letter denoting the diatonic step in question