The botanist's companion; or, Directions for the use of the microscope (1860)
Balfour, John Hutton, 1808-1884. [from old catalog] · Edinburgh, A. and C. Black · leaf 9
nvex,— the concave lenses being employed to make certainmodifications in the course of the rays passing through convex lenses,whereby their performance is rendered more exact. The magnifyingpower of a single lens is its focal length. The principal focus is Figs. 1-6. Different kinds of lenses—1.… … SPHERICAL AND CHROMATIC ABERRATIONS. O the npint to which parallel rays converge after reflection or refractioD.The focus of a double convex lens is at half the distance of a plano-convex, having the same curvature on one side. Ten inches is themean focal length of the human eye. In the use of…
Botany · Microscopy
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
