DOI Page / Citation link:
https://doi.org/10.11588/diglit.25683#0039
¥ R A CTICAL P E It S P £ C T I V E .
in the same manner E Vb is laid on the horizontal line, and determines the point
Bb, by which any lines that tend to Yb may be proportioned
V. The cross is exactly opposite and parallel to the front of the abbey, and there-
fore tends to the same vanishing, points. The rest of the drawing may be completed by
the observation of the pupil, attention being paid to what was before noticed concerning
the figures in the last example.
O X.'
Sect. 8. As the upright stone on which the title is written in the title plate may also
illustrate the principles of this example, 1 shall here mention that it is drawn upon the
same oblique construction. The vanishing point of its front is out of the limits of the
paper, but the distance or proportion point of that vanishing point is-marked Db, Va is
the vanishing point of the side of the stone, and Da is its distance or proportion point.
By help of these distances the length and thickness of the stone are determined.. The Tine
NAM is drawn parallel to the horizontal line at the corner point A, taken at pleasure*
and because the stone is supposed to be three times as long as it is thick, three divisions
are laid from A to M, each division being § of what its length would be were it opposite
or parallel to the spectator. Then, because the bottom of the front tends to the vanishing
point Vb (which is out of the limits of the plate), a line drawn from Db to M will determine
the point L. For the thickness, one division is laid from A to N, and because the bottom
of the side tends to the vanishing point Ya, a line drawn from Da to N will determine
the point B. Then A L is the perspective length, and A B the perspective thickness of
the stone, in proportion to the distance of the eye of the spectator from those points in
the plane of the picture, which denote thse points in tiie ac tual horizon, to which the
sides of the stone are directed; and in proportion to the distances of the points A, L and B
in the real object, from the plane of the picture in the directions of the sides of the object
See observ. IX. § 2. also Prob. IX. of Georm
G
PLATE
in the same manner E Vb is laid on the horizontal line, and determines the point
Bb, by which any lines that tend to Yb may be proportioned
V. The cross is exactly opposite and parallel to the front of the abbey, and there-
fore tends to the same vanishing, points. The rest of the drawing may be completed by
the observation of the pupil, attention being paid to what was before noticed concerning
the figures in the last example.
O X.'
Sect. 8. As the upright stone on which the title is written in the title plate may also
illustrate the principles of this example, 1 shall here mention that it is drawn upon the
same oblique construction. The vanishing point of its front is out of the limits of the
paper, but the distance or proportion point of that vanishing point is-marked Db, Va is
the vanishing point of the side of the stone, and Da is its distance or proportion point.
By help of these distances the length and thickness of the stone are determined.. The Tine
NAM is drawn parallel to the horizontal line at the corner point A, taken at pleasure*
and because the stone is supposed to be three times as long as it is thick, three divisions
are laid from A to M, each division being § of what its length would be were it opposite
or parallel to the spectator. Then, because the bottom of the front tends to the vanishing
point Vb (which is out of the limits of the plate), a line drawn from Db to M will determine
the point L. For the thickness, one division is laid from A to N, and because the bottom
of the side tends to the vanishing point Ya, a line drawn from Da to N will determine
the point B. Then A L is the perspective length, and A B the perspective thickness of
the stone, in proportion to the distance of the eye of the spectator from those points in
the plane of the picture, which denote thse points in tiie ac tual horizon, to which the
sides of the stone are directed; and in proportion to the distances of the points A, L and B
in the real object, from the plane of the picture in the directions of the sides of the object
See observ. IX. § 2. also Prob. IX. of Georm
G
PLATE