(This system was extensively used at the beginning of the present century, but has gradually fallen into disfavor and was finally rejected by the Paris Conference of 1954.)

31.1. Substitution is a device used to avoid the continual marking of octaves in passages that frequently change their octave. The one condition for its use is that the passage must be in notes of equal value.

31.2. A passage written in substitution is limited to a range of four octaves, the octaves being shown in ascending order from the lowest by note values, thus:

lowest octave - eighths

lower middle octave - halves

higher middle octave - wholes

highest octave - quarters

31.3. The sign indicating the commencement of a passage of substution occupies three spaces:

(1) an octave sign showing the lowest octave of the passage;

(2) the sign(put in braille bob2)

(3) one of the value signs forming the second of the signs in Table 13,
showing the value of the notes in the notes in the passage. Thus the sign (PUT IN BRAILLE BOB) indicates a passage of sixteenths whose lowest note is in the second octave.

Example 31.3-1

(a) put in the code bob2

(b)put in the code bob2

put in notes and the staff bob2

31.4. Rests of any value can occur in a passage of substitution, but a note of any other value (or even of the same value dotted) brings it to an end and must be preceded by a special octave mark.

31.5 Hand signs and expression mark (Table 18 (B)) render the re-marking of the substitution sign necessary unless (according to the practice of some countries) they are followed by dot 3.

31.6 Stem signs of any value may be used in a passage of substitution.