SCHEINER, Christoph. Oculus, hoc est: fundamentum opticum. Innsbruck: Daniel Agricola, 1619. 4o (198 x 151 mm). Engraved allegorical plate, numerous woodcut diagrams in text. (Small repair at upper inner blank margin on title, text washed.) Modern morocco. Provenance: Alain Brieux (bookplate). FIRST EDITION. "Scheiner, a Jesuit astronomer, was a pioneer in physiological optics. He demonstrated how images fall on the human retina, noting the change in curvature of the lens during accommodation, and devised the pin-hole test ('Scheiner's test') to illustrate accommodation and refraction" (Garrison-Morton 1480). NLM/Krivatsy 10364; Waller 8585. VERY RARE.