Whole note they may occasionally be put under a different line (or ledger line) in more complicated polyphonic passages, or when two instruments or vocalists are written on one staff and one is temporarily silent. The whole note and whole rest may also be used in music of free rhythm, such as Anglican chant, to denote a whole measure, irrespective of the time of that measure. The whole rest can be used this way in almost all or all forms of music. The symbol is first found in music notation from the late thirteenth century . The whole note derives from the
Grace note the bar in which they are contained - and therefore, do not require other notes to be dropped from the bar to keep the time signature intact. In bagpipe music there is extensive use of grace notes. Indeed, because the chanter is not tongued but supplied by a continuous air source from the bag, grace notes are sometimes the only way to differentiate between notes. For example, inserting a grace note between two crotchets (quarter notes) played at the same pitch is the only way to indicate them as opposed to them sounding like a single minim (half note). Various