A text book of physics, for the use of students of science and engineering (1918)
Duncan, John, d. 1941, Starling, Sydney George, 1873- · London Macmillan · leaf 633
Fig. 560.—Short-sight and its correction. Ill v dY \ 608 LIGHT CHAP. Now let f1 be the focal length of the lens L required to make v thefocal length of the combination (Fig, 560 (&)), so that the eye withthe lens in front can see clearly points <at infinity. Then 1 1 / 599). … On comparing these two equations, we see that fi = d, or, the focallength of lens required to correct this eye, is equal to the distance of the farpoint from the eye. Hypermetropia, or long-sight. In this case the focal length of thelens of the eye is too great, or the eye-ball is too short, so…
Physics
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
