Dioptrics

...ph, original: "triumphum"; completing the word "triumph" from the previous page. for when six years ago I had published the Optical Part of Astronomy original: "Opticam Astronomiae partem"; referring to Kepler’s 1604 work Ad Vitellionem paralipomena., in which I discussed the nature of vision by a new method and, as far as I know, was the first of all to argue such points about spectacles original: "perspicillis"; used here to mean lenses or eyeglasses. that remain unshaken to this day: it was fitting that I should show that those same foundations, upon which I had built the theory of vision and the effects of simple spectacles, were also sufficient to support the combination of different transparent lenses into a single tube original: "arundinem"; literally "reed," a poetic or technical term for the telescope tube.. And indeed, it could not be otherwise (which is the proof of truth) than that this demonstration be carried out by any principles other than those I have used. And since Euclid made Catoptrics original: "Catoptricen"; from the Greek word for "mirror." The study of light reflection. a branch of Optics, which deals with the reflected ray—a name derived from the primary instrument of this kind, the Mirror; and their wonderful and pleasing variety—after this example, the name Dioptrics original: "Dioptrice"; from the Greek dioptra, meaning "to see through." The study of light refraction. was born for my little book. For it deals primarily with the ray refracted by dense transparent media, both natural ones in the human eye and artificial ones in the variety of lenses; by this subject it is distinguished from Catoptrics, as one species from another. Yet Dioptrics is primary and Catoptrics secondary; because Catoptrics deals with images which cannot be understood at all without the knowledge of the eye that must be sought from Dioptrics.

      For which reason I also repeated the nature of vision and of simple original: "sim-[plicium]"; the catchword "plicium" completes the word "simplicium" (simple) at the start of the next page.