See, for example, Bede's De temporibus, written in the year 703.
2.
MaximilianBobinger, Die Alt-Augsburger Kompassmacher (Augsburg, 1966), 55–56.
3.
ErnstZinner, Astronomische Instrumente des 11. bis 18. Jahrhunderts (Munich, 1956), 95.
4.
BrydenDavid J., Whipple Museum of the History of Science catalogue 6: Sundials and related instruments (Whipple Museum, Cambridge, 1988); see sundials nos. 99–101.
5.
PenelopeGouk, The ivory sundials of Nuremberg, 1500–1700 (Whipple Museum, Cambridge, 1988).
