Robson, William: Grammigraphia; or the Grammar of Drawing. (London, 1799)

Painting can beftow its abundant pleasures but on a
few; while this is easily acquired, continually needful,
and quickly performed.

Though it may not be necefiary to recommend the
particular taste or manner of any master, as every one
having adopted the principles, will by practice form
their own stile ; yet observation should be made of all that
have excellence in Lines.

Properties of a Grammigraphic Drawing.

First.
Perfect Proportion^
Which determines the relative size and place of the
large masses, and the proportionate sub-divisions of these
into the smallest parts.

Second.
"Just Position^
Both of the figures of each mass, and of their sub-,
divisions, which includes the correct perspective repre-
sentation of the appearance of the seven real situations ;
and their parallelism to the several planes in every
variety.