nd where
it lies long and feeds the moss; and he will be careful, however few
slates he draws, to mark the way they bend together towards those
hollows (which have the future fate of the roof in them), and crowd
gradually together at the top of the gable, partly diminishing in
perspective, partly, perhaps, diminished on purpose (they are so in most
English old houses) by the slate-layer. So in ground, there is always
the direction of the run of the water to be noticed, which rounds the
earth and cuts it into hollows; and, generally, in any bank or height
worth drawing, a trace of bedded or other internal structure besides.
Figure 20 will give you some idea of the way in which such facts may be
expressed by a few lines. Do you not feel the depression in the ground
all down the hill where the footsteps are, and how the people always
turn to the left at the top, losing breath a little, and then how the
water runs down in that other hollow towards the valley, behind the
roots of the trees?

108. Now, I want you in your first sketches from Nature to aim
exclusively at understanding and representing these vital facts of form;
using the pen--not now the steel, but the quill--firmly and steadily,
never scrawling with it, but saying to yourself before you lay on a
single touch,--"_that_ leaf is the main one, _that_ bough is the guiding
one, and this touch, _so_ long, _so_ broad, means that part of
it,"--point or side or knot, as the case may be. Resolve always, as you
look at the thing, what you will take, and what miss of it, and never
let your hand run away with you, or get into any habit or method of
touch. If you want a continuous line, your hand should pass calmly from
one end of it to the other without a tremor; if you want a shaking and
broken line, your hand should shake, or break off, as easily as a
musician's finger shakes or stops on a note: only remember this, that
there is no general way of doing _any_ thing; no recipe can be given you
for so much as the drawing of a cluster of grass. The grass may be
ragged and stiff, or tender and flowing; sunburnt and sheep-bitten, or
rank and languid; fresh or dry; lustrous or dull: look at it, and try to
draw it as it is, and don't think how somebody "told you to _do_ grass."
So a stone may be round or angular, polished or rough, cracked all over
like an ill-glazed teacup, or as united and broad as the breast of
Hercules. It may be as flaky as a wafer, as powdery as a field
pu