Hall, Edwin Herbert, 1855-1938 · New York, H. Holt and company · leaf 151
to find it by experiment. For this purpose we need to havethe light come to the lens in rays nearly parallel to eachother and to the principal axis. This we can do by takingthe light from any small spot of any distant but distinctobject; for instance, a chimney or a church-spire outlinedagainst the… … Fig. 105. First Method.—Place the lens and the screen upon the rod, as in Fig. 105, and point the rod at some distant object, seen against the sky, in such a way that the light from this object will pass from the lens and then fall upon the screen. Move the screen back and forth * Bee Appendix I,…
Physics
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
