| 80 | 81 | 82 | 83 | 84 |
| 1 | 306 | 613 | 919 | 1225 |
|
dark room intersect at a point which is nearer to the opening in
proportion as the opening is narrower. To prove this let a b be an
object in light and shade which sends not its shadow but the image
of its darkened form through the opening d e which is as wide as
this shaded body; and its sides a b, being straight lines (as has
been proved) must intersect between the shaded object and the
opening; but nearer to the opening in proportion as it is smaller
than the object in shade. As is shown, on your right hand and your
left hand, in the two diagrams a b c n m o where, the
right opening d e, being equal in width to the shaded object a
b, the intersection of the sides of the said shaded object occurs
half way between the opening and the shaded object at the point c.
But this cannot happen in the left hand figure, the opening o
being much smaller than the shaded object n m.
It is impossible that the images of objects should be seen between
the objects and the openings through which the images of these
bodies are admitted; and this is plain, because where the atmosphere
is illuminated these images are not formed visibly.
When the images are made double by mutually crossing each other they
are invariably doubly as dark in tone. To prove this let d e h
be such a doubling which although it is only seen within the space
between the bodies in b and i this will not hinder its being
seen from f g or from f m; being composed of the images a
b i k which run together in d e h.
8
2
Page
Quick Jump
|