St Nicholas [serial] . ough the hole on clown to where it strikes thecardboard (C), and of course makes a tiny whitespot. The ray (J-K) from the body of the candlewill not be so bright, because the body of the can-dle is not as bright as the body of the flame. Theblack wick will not cast any rays at all and sowill appear black on the screen. The backgroundfor the same reason will be black. There are millions of rays radiating from eachpoint of the candle, and if they all struck thescreen (C) the images of the many points wouldso overlap that there would result merely anilluminated surface, as
St Nicholas [serial] . ough the hole on clown to where it strikes thecardboard (C), and of course makes a tiny whitespot. The ray (J-K) from the body of the candlewill not be so bright, because the body of the can-dle is not as bright as the body of the flame. Theblack wick will not cast any rays at all and sowill appear black on the screen. The backgroundfor the same reason will be black. There are millions of rays radiating from eachpoint of the candle, and if they all struck thescreen (C) the images of the many points wouldso overlap that there would result merely anilluminated surface, as you can readily see if youremove the cardboard (B). When this screenis in place, only a single ray can pass through thehole from each point, say D-D, for the others from that point, as D-E, D-F,D-G, D-H, etc., are stopped by the screen. This be able to bend all the rays that come from apoint so they will meet at a common point on thescreen on which the image is thrown. The imageis then said to be in FIG. I. diagram to show course of the rays. is also the case with the millions of points form-ing the surface of the candle. This pinhole does not let enough light through,but if we make it larger so many rays comethrough from the same point as to blur theimage. To use a larger opening we need a lens,which is a piece of clear glass so formed as toVol.
Size: 2331px × 1072px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, bookidstnicholasserial371dodg
