And this situation of them being a circumstance
which usually attends the vision of distant objects, we may from hence
account for (what is commonly observed) an object's appearing of
different magnitude, even with respect to its horizontal extension, on
the top of a steeple, for example, an hundred feet high to one standing
below, from what it would if placed at an hundred feet distance on a
level with his eye. For it hath been shown that the judgment we make on
the magnitude of a thing depends not on the visible appearance alone, but
also on divers other circumstances, any one of which being omitted or
varied may suffice to make some alteration in our judgment. Hence, the
circumstances of viewing a distant object in such a situation as is
usual, and suits with the ordinary posture of the head and eyes being
omitted, and instead thereof a different situation of the object, which
requires a different posture of the head taking place, it is not to be
wondered at if the magnitude be judged different: but it will be demanded
why an high object should constantly appear less than an equidistant low
object of the same dimensions, for so it is observed to be: it may indeed
be granted that the variation of some circumstances may vary the judgment
made on the magnitude of high objects, which we are less used to look at:
but it does not hence appear why they should be judged less rather than
greater? I answer that in case the magnitude of distant objects was
suggested by the extent of their visible appearance alone, and thought
proportional thereto, it is certain they would then be judged much less
than now they seem to be (VIDE sect.
Pages:
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62