Note 357 — BOOK V.
William Julius Mickle translation
That sage device.—The astrolabe, an instrument of infinite service in navigation, by which the altitude of the sun, and distance of the stars is taken. It was invented in Portugal during the reign of John II. by two Jewish physicians, named Roderic and Joseph. It is asserted by some that they were assisted by Martin of Bohemia, a celebrated mathematician.—Partly from Castera. Vid. Barros, Dec. 1. lib. iv. c. 2.