Ashmolean The Elements of Drawing, John Ruskin’s teaching collection at Oxford

Measure and copy this, with thick dry colour in your brush. It will show you in the outset, that refinement in design does not depend on the minuteness or fineness of work, but on its precision and care. These lines look coarse, but you will find they cannot be altered in the curvature even by a small fraction of an inch without losing grace, and that it is very difficult to follow their curvatures without altering them, owing to their continual subtlety of change.

Also, it is not possible to express the general characters of growth in noble vegetation, with fewer or simpler lines. It is easy to make leaves and stems graceful, but not to make them springy and vigorous as well: and the especial beauty of this group of foliage as terminating the rod of Apollo is the strength with which it is springing, and the visible presence in the god’s virgin sceptre of the life which in the king’s is lost. Look at the words of the vow of Achilles.

Note the quaint little leaf at the bottom, which you would think had been drawn wrongly. In vulgar design, everything is equally graceful; but in fine design, there are local uncouthnesses, as, in fine music, discords.

For the rest, the diminution of the stem for each leaf is much greater than it would be in reality: this is a necessary conventionalism, in order to terminate the strong rod within brief limits; but nothing can be more perfect than its rendering of the universal law of ramification; and even the apparent coarseness of the lines is only caused by enlargement of scale, for this example is much magnified; in the original it is only about an inch high, and the lines are thickened by cross strokes, not by deeper engraving.