This system of neumes was in some ways a retrogression from the Greek letter system, for the neumes indicated neither definite pitches nor definite tone-lengths. But it had this advantage over the Greek system, that the position of the signs on the page indicated graphically to the eye the general direction of the melody, as well as giving at least a hint concerning the relative highness or lowness of each individual tone (the so-called diastematic system), and this was a great aid to the eye in singing, just as the relative highness and lowness of notes on the modern staff is of great value in reading music at the present time. Thus although the neumae did not enable one to sing a new melody at sight as our modern staff notation does, yet they served very well to recall to the eye the general outline of a melody previously learned by ear and therefore enabled the singer (the system was used for vocal music only) to differentiate between that particular melody and the dozens of others which he probably knew. Neume notation was used mostly in connection with the "plain-song melodies" of the Church, and since the words of these chants were sung as they would be pronounced in reading, the deficiency of the neume system in not expressing definite duration values was not felt. But later on with the rise of so-called "measured music" (cf. invention of opera, development of independent instrumental music, etc.), this lack was seen to be one of the chief disadvantages of the system.
The elements of neume-writing as given by Riemann in his Dictionary of Music are:
"(1) The signs for a single note: Virga (Virgula) and Punctus (Punctum). (2) The sign for a rising interval: Pes (Podatus). (3) The sign for a falling interval: Clinis (Flexa). (4) Some signs for special manners of performance: Tremula (Bebung), Quilisma (shake), Plica (turn), etc. The others were either synonyms of the above-named or combinations of them...."
Since music in the middle ages was always copied by hand, it will readily be understood that these neumae were not uniform either in shape or size, and that each writer made use of certain peculiarities of writing, which, although perfectly intelligible to himself, could not readily be interpreted by others (cf. writing shorthand). Here then we observe the greatest weakness of the neume system—its lack of uniformity and its consequent inability accurately to express musical ideas for universal interpretation.
Examples of several neumes are given merely in order to give the beginner a general idea of their appearance.
Virga
or
. Punctus