acts. The sketch preserves for him the evanescent
effects of nature, which the study would not so entirely, because not
so simply, grasp. The sudden storm approaches; the fleeting cloud
shadow; or the last gleam of afterglow; these, as well as the more
permanent, but equally charming effects of mass against mass of wood
and sky, or of meadow and hill, he can only store up for future use or
reference in his sketches.

=Main Idea Only.=--In the making of the sketch, then, no problem
should come in but that of the expression of the main idea,--no
problem of drawing or of manipulation of color. To get the idea
expressed in the most direct and immediate and convenient way,
anything will do to sketch on or with; that which presents the least
difficulty is the best. The matter of temperament, of course, comes
in largely, and technical facility. That which you can use most
freely, use in your sketching, and keep for other occasions the new
means or medium. Use freely, if you can, black and white for whatever
black and white will express, and pigment for all color effects. Oil
for greatest certainty and facility of correction.

=Quick Work.=--Make your sketch at one sitting, or you will have
something which is not a sketch. Work long enough, and it may be a
study; but more than one sitting makes it neither one thing nor the
other. To say nothing of the fact that the conditions are unlikely to
be exactly the same again, you are almost sure on the second working
to have lost the first impression,--the freshness and directness of
purpose which the first impress gives; and this is the very heart of a
sketch. You must never lose sight of what was the original purpose of
it; never forget what it was which first made you want to paint it. No
matter what else you get or do not get, if you lose this you lose all
that can give it life or reality.

The very fact that you have limited yourself to one working makes you
concentrate on that which first caught your attention, and that is
what you want to seize.

Overworkings and after-paintings will only interfere with the
directness and force with which this is expressed.

Remember that nature is never at rest. You must catch her on the wing,
and the more quickly you do it the more vivid will be the effect.

[Illustration: =The River Bank.= _D. Burleigh Parkhurst._
Half-hour sunset sketch.]

"Nature is economical. She puts her lights and darks only where she
needs them." Do the same,