1. In working on this project I was able to overcome some of the limitations in my
knowledge of codicology, paleography, and medieval astronomy by consulting Paul Saenger,
Richard Clement, John Friedman, and Sigmund Eisner; despite their generous aid, I fear that I still
have much to learn, and hope eventually to produce a much more complete and definitive study of
Ayer MS 746. I studied the manuscript directly and began preliminary investigations at the
Newberry Library thanks to a Short-term Fellowship during July 5-15, 1983.
2. See the various magisterial studies of José Maíra Millás
Vallicrosa collected in Assaig d'història de les idees físiques i
matemàtiques a la Catalunya medieval (Barcelona: Institució Patxot, 1931),
Estudios sabre histaria de la ciencia española (Barcelona: Consejo Superior de
Investigaciones Cientificas, 1949), Las tablas astronómicas del Rey Don Pedro El
Ceremonioso (Madrid: Consejo Superior de Investigaciones Cientificas, 1962), Nuevos
estudios sabre historia de la ciencia española (Barcelona: Consejo Sup
