The Elements of Perspective / arranged for the use of schools and intended to be read in connection with the first three books of Euclid

by John Ruskin

Let A B, [Fig. 28.], be the curve.

Inclose it in a rectangle, C D E F.

Fix the position of the point C or D, and draw the rectangle. (Problem VIII. [Coroll. I.])[Footnote 20] ]

Let C D E F, [Fig. 29.], be the rectangle so drawn.

Fig. 29.

If an extremity of the curve, as A, is in a side of the rectangle, divide the side C E, [Fig. 29.], so that A C shall be (in perspective ratio) to A E as A C is to A E in [Fig. 28.] (Prob. V. [Cor. II.])

Similarly determine the points of contact of the curve and rectangle

e

,