The geography of the heavens : and class-book of astronomy : accompanied by a celestial atlas (1860)
Burritt, Elijah H. (Elijah Hinsdale), 1794-1838, Mattison, Hiram, 1811-1868 · New York : Mason Brothers · leaf 313
DOUBLE CONVEX—FOCAL DISTANCE. … 674. What is a lens? Draw and describe different kinds. 675. Refracting power ofdouble-convex lens? Focal distance? Diagram, and illustrate. 676. How focal dis-tance governed ? Diagram, and illustrate. 677. What is the focal distance of a REFLECTION AND REFRACTION OF LIGHT. 311 It must be borne in…
Constellations · Stars
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
