DOI Page / Citation link:
https://doi.org/10.11588/diglit.8#0199
{ 19S j
will correct; and experience certainly• evinces the truth
of his assertion : though Perrault combats the princi-
ple, and attempts to prove the optical effect of approxi-
mation, would be the reverse, as the increased shade
would, when columns are very close together, cause
them to appear less in diameter : but this is little better
than chicanery; for, though columns of a sable hue will,
doubtless, appear smaller than columns of white or very
light coloured marble ; the question is, in Vitruvius's
reasoning, not about the hue of the columns, but of the
reduction or lessening of the glare of the ambient light,
the degrees of which are diminished in proportion, as
the intervals are contracted ; but no change is caused in
the colour of the columns themselves. And_daily expe-
rience evinces, that objects, with which we are familiar
only as standing in the open air, suppose statues or vases,
on a lawn, when brought into a hall, or a saloon, will
appear very considerably larger, than we before judged
them to be. This principle of optical effects, therefore,
is sound and true; and not of the fallacious nature of
our master's other notions of optics, which induced him
to order the changes of attitude, from erect to over-
hanging, in order to appear perpendicular; and columns,
50 feet high, to be contracted in their top diameter only
5 minutes, from the notion that the great height will
induce a persuasion of the contraction being 10 minutée
as in columns of about 15 feet high. Perrault has suc-
cessfully combated these erroneous conclusions in the 8
chap. 2 part of his treatise on the five kinds of columns,
made English by Mr. James of Greenwich, in the year
1708. And, though many ingenious artists have imbi-
bed something of these ancient dregs of false optics, yet
it appears not that the ancients themselves practised
sucb
will correct; and experience certainly• evinces the truth
of his assertion : though Perrault combats the princi-
ple, and attempts to prove the optical effect of approxi-
mation, would be the reverse, as the increased shade
would, when columns are very close together, cause
them to appear less in diameter : but this is little better
than chicanery; for, though columns of a sable hue will,
doubtless, appear smaller than columns of white or very
light coloured marble ; the question is, in Vitruvius's
reasoning, not about the hue of the columns, but of the
reduction or lessening of the glare of the ambient light,
the degrees of which are diminished in proportion, as
the intervals are contracted ; but no change is caused in
the colour of the columns themselves. And_daily expe-
rience evinces, that objects, with which we are familiar
only as standing in the open air, suppose statues or vases,
on a lawn, when brought into a hall, or a saloon, will
appear very considerably larger, than we before judged
them to be. This principle of optical effects, therefore,
is sound and true; and not of the fallacious nature of
our master's other notions of optics, which induced him
to order the changes of attitude, from erect to over-
hanging, in order to appear perpendicular; and columns,
50 feet high, to be contracted in their top diameter only
5 minutes, from the notion that the great height will
induce a persuasion of the contraction being 10 minutée
as in columns of about 15 feet high. Perrault has suc-
cessfully combated these erroneous conclusions in the 8
chap. 2 part of his treatise on the five kinds of columns,
made English by Mr. James of Greenwich, in the year
1708. And, though many ingenious artists have imbi-
bed something of these ancient dregs of false optics, yet
it appears not that the ancients themselves practised
sucb