Pedro Nunes (pĕ´drŏŏ nōō´nəsh), Lat. Petrus Nonius, 1502–1578, Portuguese mathematician, geographer, and writer on navigation and geometry. He was the first (1534) to demonstrate an instrument for measuring angles and was the reputed inventor of the rhumb line. He became royal cosmographer in 1529. From 1544 to 1562 he was professor of mathematics at Coimbra. Two of his works are De crepusculis (1542) and De arte atque ratione navigandi (1546).
"Nunes, Pedro." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (February 17, 2018). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/nunes-pedro
"Nunes, Pedro." The Columbia Encyclopedia, 6th ed.. . Retrieved February 17, 2018 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/nunes-pedro