DOI Page / Citation link:
https://doi.org/10.11588/diglit.18826#0078
58 ON PERSPECTIVE. [LECT. II.
right lines, have little difficulty ; fmce we have accu-
rate data to conduct us: but, circular, or curved,
lines offer no fuch data, and therefore oblige us to call
in affiftance from our worthy friends, whofe tendency
is regular and determinate.
A circle, is a figure fo complete and perfect in itfelf,
that it eludes every attempt to difcover to what point
in perfpect.ive any part of its line has any peculiar re-
jation: any relation ot which we may take advantage:
the readied way therefore to obtain the reprefentation
of a circle, is, by infcribing it in a fquare of equal dia-
meter, and, taking advantage of thofe points where-
in the two figures correfpond ; hereby we obtain a
fketcb, or fkeleton, of the circle; which is capable of
more, or lets, accuracy, according to the divifions,
and fab divifions, of the original fquare. Eight points
are generally thought fufficient in practice ; but more
may eafily be obtained, if the fquare be large enough
to render them necelfarv.
Nor on this occafion onlv is a fquare of great uti-
lity ; a little confideration will find it a very confe-
quential figure ; as well, becaufe its form is perpetu-
ally occurring, (as is likewife a circle) as becaufe any
other figure infcribed within it, by properly fub-
dividing the fquare, may be reprefented with little
trouble.
Having faid a fquare, and a circle, are figures per-
petually occurring, give me leave to authenticate my
pofition. If we examine objects in the ftreet;—the
fronts ofhoufes are fquare, their windows fquare, their
doors
right lines, have little difficulty ; fmce we have accu-
rate data to conduct us: but, circular, or curved,
lines offer no fuch data, and therefore oblige us to call
in affiftance from our worthy friends, whofe tendency
is regular and determinate.
A circle, is a figure fo complete and perfect in itfelf,
that it eludes every attempt to difcover to what point
in perfpect.ive any part of its line has any peculiar re-
jation: any relation ot which we may take advantage:
the readied way therefore to obtain the reprefentation
of a circle, is, by infcribing it in a fquare of equal dia-
meter, and, taking advantage of thofe points where-
in the two figures correfpond ; hereby we obtain a
fketcb, or fkeleton, of the circle; which is capable of
more, or lets, accuracy, according to the divifions,
and fab divifions, of the original fquare. Eight points
are generally thought fufficient in practice ; but more
may eafily be obtained, if the fquare be large enough
to render them necelfarv.
Nor on this occafion onlv is a fquare of great uti-
lity ; a little confideration will find it a very confe-
quential figure ; as well, becaufe its form is perpetu-
ally occurring, (as is likewife a circle) as becaufe any
other figure infcribed within it, by properly fub-
dividing the fquare, may be reprefented with little
trouble.
Having faid a fquare, and a circle, are figures per-
petually occurring, give me leave to authenticate my
pofition. If we examine objects in the ftreet;—the
fronts ofhoufes are fquare, their windows fquare, their
doors