udiorum_ is precisely
analogous to that of Holbein. The lines of these etchings are to
trees, rocks, or buildings, absolutely what these of Holbein are; not
suggestions of contingent grace, but determinations of the limits of
future form. You will see the explanatory office of such lines by
placing this outline over my drawing of the stone, until the lines
coincide with the limits of the shadow. You will find that it
intensifies and explains the forms which otherwise would have escaped
notice, and that a perfectly gradated wash of neutral tint with an
outline of this kind is all that is necessary for grammatical
statement of forms. It is all that the great colorists need for their
studies; they would think it wasted time to go farther; but, if you
have no eye for color, you may go farther in another manner, with
enjoyment.

35. Now to go back to Turner.

The _first_ great object of the _Liber Studiorum_, for which I
requested you in my sixth Lecture[7] to make constant use of it, is
the delineation of solid form by outline and shadow. But a yet more
important purpose in each of the designs in that book is the
expression of such landscape powers and character as have especial
relation to the pleasures and pain of human life--but especially the
pain. And it is in this respect that I desired you (Sect. 172) to be
assured, not merely of their superiority, but of their absolute
difference in kind from photography, as works of disciplined design.

[Footnote 7: "Lectures on Art, 1870," Sec. 170.]

[Illustration: NEAR BLAIR ATHOL.

From the painting by Turner.]

36. I do not know whether any of you were interested enough in the
little note in my catalogue on this view near Blair Athol, to look for
the scene itself during your summer rambles. If any did, and found it,
I am nearly certain their impression would be only that of an extreme
wonder how Turner could have made so little of so beautiful a spot.
The projecting rock, when I saw it last in 1857, and I am certain,
when Turner saw it, was covered with lichens having as many colors as
a painted window. The stream--or rather powerful and deep Highland
river, the Tilt--foamed and eddied magnificently through the narrowed
channel; and the wild vegetation in the rock crannies was a finished
arabesque of living sculpture, of which this study of mine, made on
another stream, in Glenfinlas, only a few miles away, will give you a
fair idea. Turner has absolutely stripped the