light from a portion ofthe source, the amount of lightincreases as the points approachG and F, the outer boundary ofthe shadow. Consider any pointbetween E and G; join this pointto C and produce the line tomeet AB, then clearly light fromany portion of the source betweenA and the line so drawn… … B 10 LIGHT. [CH. I lines AC, BD converge and may meet before reaching thescreen; suppose they do meet, as at K. Then if the screenwere placed between the opaque object and K there wouldbe umbra and penumbra as before; if the screen passedthrough K the umbra would be reduced to a point, and ifthe…
Heat · Light
Internet Archive · California Digital Library · Public Domain Mark 1.0. Free to use for anything.
