hade, shutting the light gradually up, and
putting in the dark cautiously on the dark side. You need not plague
yourself about accuracy of shape, because, till you have practised a
great deal, it is impossible for you to draw that shape quite truly, and
you must gradually gain correctness by means of these various exercises:
what you have mainly to do at present is, to get the stone to look solid
and round, not much minding what its exact contour is--only draw it as
nearly right as you can without vexation; and you will get it _more_
right by thus feeling your way to it in shade, than if you tried to draw
the outline at first. For you can _see_ no outline; what you see is only
a certain space of gradated shade, with other such spaces about it; and
those pieces of shade you are to imitate as nearly as you can, by
scrawling the paper over till you get them to the right shape, with the
same gradations which they have in Nature. And this is really more
likely to be done well, if you have to fight your way through a little
confusion in the sketch, than if you have an accurately traced outline.
For instance, I was going to draw, beside _a_, another effect on the
stone; reflected light bringing its dark side out from the background:
but when I had laid on the first few touches, I thought it would be
better to stop, and let you see how I had begun it, at _b_. In which
beginning it will be observed that nothing is so determined but that I
can more or less modify, and add to or diminish the contour as I work
on, the lines which suggest the outline being blended with the others if
I do not want them; and the having to fill up the vacancies and conquer
the irregularities of such a sketch, will probably secure a higher
completion at last, than if half an hour had been spent in getting a
true outline before beginning.

In doing this, however, take care not to get the drawing too dark. In
order to ascertain what the shades of it really are, cut a round hole,
about half the size of a pea, in a piece of white paper, the colour of
that you use to draw on. Hold this bit of paper, with the hole in it,
between you and your stone; and pass the paper backwards and forwards,
so as to see the different portions of the stone (or other subject)
through the hole. You will find that, thus, the circular hole looks like
one of the patches of colour you have been accustomed to match, only
changing in depth as it lets different pieces of the stone be se