Mensural notation recoverable from the modern text. While 19th and early 20th century editions of Renaissance music often preserved the large note values of the originals, including breves and longs, most modern editions will use scaled-down note values in order to match modern reading habits regarding tempo and beat structure. For 16th century music, a frequent scheme is diminution by a factor of 2 (i.e., rendering semibreves as modern minims), in a modern "alla breve" bar. Older music might be diminished by a factor of 4 (rendering semibreves as crotchets) or sometimes 8 (rendering breves as crotchets). For 13th-century pieces, diminution by
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