12559on PERSPECTIVE.
drawn upon the Geometrical Plane, and the
principal Points of the Objects without the ſaid
Plane, need only be thrown into Perſpective.
Which being once obtained, he may make uſe
of theſe Appearances ſo found, as a Rule where-
by the reſt may be compleated by the Eye, with-
out running the Riſque of committing ſome
conſiderable Fault, which by this Means may be
avoided.
principal Points of the Objects without the ſaid
Plane, need only be thrown into Perſpective.
Which being once obtained, he may make uſe
of theſe Appearances ſo found, as a Rule where-
by the reſt may be compleated by the Eye, with-
out running the Riſque of committing ſome
conſiderable Fault, which by this Means may be
avoided.
CHAP. IV.
Of the Practice of Peſpective upon the Per-
ſpective Plane ſtill conſider’d as being upright.
ſpective Plane ſtill conſider’d as being upright.
IT often happens that Painters offend all
Rules of true Appearance when they paint
Pictures to ſtand aloft, to be ſeen Sideways, or at
a confiderable Diſtance. Their Cuſtom is to
paint Pictures to be view’d, after the ſame Man-
ner as they themſelves look at them when they
are working; whence in the following Caſes,
this Practice of theirs will be uſeleſs; and ſo to
avoid enormous Faults, they are neceſſitated to
have recourſe to Perſpective But what has been
ſaid in the laſt Chapter, does not reach theſe
particular Caſes; therefore we ſhall here add ſome
new Problems, which together with the former
ones, will take in all Caſes.
Rules of true Appearance when they paint
Pictures to ſtand aloft, to be ſeen Sideways, or at
a confiderable Diſtance. Their Cuſtom is to
paint Pictures to be view’d, after the ſame Man-
ner as they themſelves look at them when they
are working; whence in the following Caſes,
this Practice of theirs will be uſeleſs; and ſo to
avoid enormous Faults, they are neceſſitated to
have recourſe to Perſpective But what has been
ſaid in the laſt Chapter, does not reach theſe
particular Caſes; therefore we ſhall here add ſome
new Problems, which together with the former
ones, will take in all Caſes.
Problem I.
75.
To throw Figures which are in the Geometri-
cal Plane into Perſpective, when the Eye is at ſo great
a Diſtance that it cannot be denoted in the
cal Plane into Perſpective, when the Eye is at ſo great
a Diſtance that it cannot be denoted in the
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