Gage, Alfred P. (Alfred Payson), 1836-1903, Fessenden, C · Toronto : W.J. Gage · leaf 375
er of the lens. If the paper is kept at the principal focus for a shorttime it will takefire. Hence, thisis the focus ofheat as well as ofligJit. The reasonis apparent whyconvex lenses aresometimes calledburning glasses.A pencil of raysemitted from the principal focus F (Fig. 265), as a…
Physics
Internet Archive · University of Toronto Libraries · Public Domain Mark 1.0. Free to use for anything.
