MENSURABLE MUSIC. 323 MENSURABLE MUSIC. (triple time) :ud i in iicrfccliis ((liii)k'). Tcmpus was thvis also subiliviiU'd into prrfcctum and impcrfrcliiiii : wlicroas in the case of iirolalin this division was desiijnated as tnajor and iiiiiKtr. The following talile gives a complete view of this system with the various signatures: Modus major perfect us Modus major imperfectus, . . . Modus minor perfectus Modus minor imperfectus, .... Tempus perfectum Terapus imperfectum, Prolatio major, . . Prolatio minor, . . The sign of the modus major was the same for the perfectus and imperfectus. The following sign for the modus miiuir determined the modus major. If the sign {s was followed by or III, it was modus major perfectus; if followed by or II , it was modus major imperfectus. The length of the vertical bars had reference to the modus miiwr. the long bars indicating the per- fectus, the short ones the imperfectus. The num- ber of vertical bars referred to the division of the large into two or three longs. The prolatio sign appeared only in connection with the tempus sign. Thus O meant tempus perfectum, pro- latio major; Q tempus imperfectum, prolatio major. If the tempus sign appeared without a dot it always meant that prolatio minor was un- derstood. The following table will make tiiis clear: _ ( Modns major perfectus. - 1 Modus iniuor perfectua.
- i Teiiipng perfectum.
( Prolatio major. ( Modus major perfectus. Modus minor imperfectus. m ^E Alteratio was the doubling of the time-value of the second of two notes of the same l<ind when a, tripartite note of the next larger kind followed. Generally the two smaller notes stood between two of the larger kind, or were separated from the following notes of equal or smaller value by 1 ^ =3i=l . ( 1 t=: = 3 S) , 1 ^ ' =3^. 1 ^ =3^, 1 ^ =3o . 1 W =3 O , 1 -^ =3 <1> , 1 O =3<!> , H lll'll III. II o c • within Tempus sign. no dot. a punctum divisionis. Thus in tempus perfectum, (Q, tripartite) {=4 <y<y fs^ would be expressed in modern notation (values reduced one-half) An important factor in the theory of mensur- able music was the color of the notes. The ordinary note was black. In the fourteenth cen- tury a red note (notula rubra) was used. Origi- nally this red note was used instead of signa- tures to denote a change from perfectio to im- perfectio or vice versa. Soon it was definitely used to indicate imperfectio only. For want of red color, it was often left open or white (notula alba ) , and during the fifteenth century the white note had the same meaning as the red note of the fourteenth. When finally the white notes were geneially adopted (during the sixteenth and seventeenth centuries), imperfectio was denoted by the black note (notula nigra). ( Modus major imperfectus. - 1 Modus miiior perfectus. - 1 Tempus imperfectum. ' Prolatio major. m z^^3 1 Tempus perfectum ( Prolatio minor. The time-value of the different notes as fixed by these signs or signatures was known as the integer valor notarum. But these fundamental values could be changed by means of augmenta- tio, diminutio, and proportio. Dimiinitio reduced the value of the notes in triple time to one-third, in duple time to one-half of the original value. It was indicated by a vertical line through the signature (t) d . ci" by affixing a number to the tempus sign (_) 2. or Q 3. Tiiue indicated thus always denoted a lively tempo, corresponding to the modern allegro. Augmentatio signified the restoration of the integer valor of notes reduced by diminutio. It was indicated by writing the i ordinary sign of the integer color O C ■ ■'^ i change of the integer valor by means of fractions ' was known as proportio. Thus -^ meant that the ! time was to be accelerated, so that three breves I now had the same duration as one breve of in- teger valor. But ^ meant the opposite, viz. that the time w'as to be retarded, so that one breve now had the same duration as three breves of the integer valor. A special kind of proportio w.is that indicated by -|, known as hernial id. Modus major imperfectus. AIoilus minor imperfectus. ■'I " 'i Tempus imperfectum. ( Prolatio miaor. A group of two or more notes to be sung on one syllable was called ligatura. When only two notes were given to one syllable, they were written as one and called figura obligua. pE(^^iEga^)^ In ligatures of more than two notes the time- value of the individual notes was not deter- mined from their actual shape but from their position. The value of the first note could be a breve or a long. In the former case the term proprietas, in the latter iniproprietas, w'as ap- plied. If the second note was lower than the first, proprietas was indicated by a vertical line (Cauda) downward <m the left side of the first ^0^, note ; if the second note was higher, the Cauda was wanting, p . In both cases the first note is breve. Imprnprieias was indicated by adding the Cauda to the first note if the sec- ond was higher, and omitting it if the second was lower: l-i^S , nn . Here both first notes are longs. '
