An introduction to perspective, drawing, and painting in a series of pleasing and familiar dialogues between the author's children : illustrated by appropriate plates and diagrams, and a sufficiency of practical geometry : and a compendium of genuine instruction ... (1815)
Hayter, Charles, 1761-1835 · London : Black, Parry and Co. · leaf 252
197 Whenever you would make a small copy of a picture, divide the original by whole numbers, so that the copy may measure exactly one half, one third, fourth, fifth, sixth, seventh, or eighth, &c., part of the original, both in height and width, because a fractional size will not produce an… … touches the diagonal, and from that point the corresponding width or length, will be truly determined. J. Innes, Printer, Wells-street, Oxford-street, London.
Perspective · Drawing · Painting · Color
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.