A treatise on the astrolabe addressed to his son Lowys - Chaucer, Geoffrey, -1400.; Māshāʾallāh, 730?-815?; Skeat, Walter W. (Walter William), 1835-1912. (London : Published for the Early English Text Society by H. Milford, Oxford University Press, 1872)
Appended is "Astrolabium Messehalle" (p. 88-104)--the Latin treatise which was evidently one of the sources from which Chaucer drew largely. cf. Pref., p. xxiv.
Reproduction of the original from the Huntington Library.
Keywords: Astrolabes