Burn, Robert Scott · London : Ingram, Cooke, and Co. · leaf 66
cil is called its axis (c d, fig. 12); that the axis of anypencil in passing through a lens undergoes so little divergence or refrac-tion, that it may practically be said to continue a straight line ; and lastly,that with a double lens equally convex on both sides, the distance of thefocus will be… … fig. 13. of its innumerable radiating points, imagine three pencils of rays (A C B,A D B, A E B) to fall upon the lens. From the nature of a convex lens,as just explained, the axis of each pencil will pass straight through the lens,but its diverging rays will be collected on the axis in a focal…
Drawing · Wood-engraving
Internet Archive · Getty Research Institute · Public Domain Mark 1.0. Free to use for anything.
