e an untrue circle, else the line could not be
thicker in one place than another. Hence all "force," as it is called,
is gained by falsification of the contours; so that no artist whose eye
is true and fine could endure to look at it. It does indeed often happen
that a painter, sketching rapidly, and trying again and again for some
line which he cannot quite strike, blackens or loads the first line by
setting others beside and across it; and then a careless observer
supposes it has been thickened on purpose; or, sometimes also, at a
place where shade is afterwards to enclose the form, the painter will
strike a broad dash of this shade beside his outline at once, looking as
if he meant to thicken the outline; whereas this broad line is only the
first instalment of the future shadow, and the outline is really drawn
with its inner edge. And thus, far from good draughtsmen darkening the
lines which turn away from the light, the _tendency_ with them is rather
to darken them towards the light, for it is there in general that shade
will ultimately enclose them. The best example of this treatment that I
know is Raphael's sketch, in the Louvre, of the head of the angel
pursuing Heliodorus, the one that shows part of the left eye; where the
dark strong lines which terminate the nose and forehead towards the
light are opposed to tender and light ones behind the ear, and in other
places towards the shade. You will see in Fig. 11. the same principle
variously exemplified; the principal dark lines, in the head and drapery
of the arms, being on the side turned to the light.

All these refinements and ultimate principles, however, do not affect
your drawing for the present. You must try to make your outlines as
_equal_ as possible; and employ pure outline only for the two following
purposes: either (1.) to steady your hand, as in Exercise II., for if
you cannot draw the line itself, you will never be able to terminate
your shadow in the precise shape required, when the line is absent; or
(2.) to give you shorthand memoranda of forms, when you are pressed for
time. Thus the forms of distant trees in groups are defined, for the
most part, by the light edge of the rounded mass of the nearer one being
shown against the darker part of the rounded mass of a more distant one;
and to draw this properly, nearly as much work is required to round each
tree as to round the stone in Fig. 5. Of course you cannot often get
time to do this; but if you