Information on differentia
In the original Cantus index for this manuscript, differentiae were assigned a two-digit code that identified the last note of each differentiae and used a number to distinguish between differentiae in the same mode that shared the same last note.
Inventory of Chicago, Art Institute of Chicago, Mrs. William E. Kelley Collection, 1911.142b. Edited by Alessandra Ignesti. In: Cantus Manuscript Database for Latin Ecclesiastical Chant: Inventories of Chant Sources. Directed by Debra Lacoste (2011-), Terence Bailey (1997-2010), and Ruth Steiner (1987-1996). Web developer, Jan Kolácek (2011-).
Images: Antiphonary, Mrs. William E. Kelley Collection, Art Institute of Chicago