Cox, David: A series of progressive lessons intended to elucidate the art of painting: with introductory illustrations on perspective and drawing with pencil (London, 1845)

The original intent of the Series of Progressive Lessons was, that it might be found
of utility in the absence of a good Drawing Master : how far this end has been accomplished,
is evinced by the demand for another Edition.
But in order to explain the system adopted in the present improved state of the Art, it
was necessary to discard the preceding Work altogether, and to produce another entirely new.
In the present Work, new exertions have been made towards improvement; the subjects
(all drawn from nature) are treated progressively in Pencil, Sepia, and Colours, and executed
in a style to render them Fac Similes of the original Drawings. In the elucidation of the
processes by which these examples are executed, the aim has been to simplify the whole, and
to render it accessible to those who are inclined to consider it worthy of that persevering
attention which is certain to subdue every difficulty.