Page 202

                            SKETCHING AND STUDYING
so very readily by chalking the thread, and rapping it against the picture,
precisely as a carpenter
uses his chalk-line.  Vanishing-points which may fall out of the lijrnits
of the picture may be man-
aged in the same manner.
  It is frequently desirable, in the progress of a work, to recover certain
perspective lines and
points which may have become obliterated, or worked out of place; and, to
this end, a thread will
be generally found most serviceable, as it can he applied even over moist
oil-colors, without
injury.   Where we merely require the guidance of a horizontal line, a fine
thread, stretched in its
place, obviates all necessity for erasures, and can at any time be renewed.
 For this purpose.
the points on the edge of the picture, where such line falls, should always
be preserved.  If a
necessity for the recovery of a vanishing-point is likely to be of frequent
recurrence-as, for
instance, in a landscape with buildings, or in architectural subjects-the
picture, if on canvas,
tn~y be even pierced at such point with a fine needle, and a thread passed
through, for the pur-
pose, without injury-a touch of color, when it is no longer required, being
sufficient to obliterate
every trace of it.
  In making out perspective drawings, on paper stretched on a board or table,
much time may
be saved, and accuracy insured, by fixing fine needles at the points of sight,
principal vanishing-
points, distance, etc.
  These few, of many other expedients which might be suggested, have been
given in the hope
that they may tend to do away with the dread, which too many have, of encountering
"the worry
of perspective"-without which they may rest assured that no one ever
yet went far successfully
in art, and that no one ever will.
  43. There are many cases in which it may be required that the sketcher
should employ a sort
of short-hand method of securing memoranda, which may be afterward elaborated
quite as well,
if not better, under more convenient circumstances.  Thus, in sketching buildings,
it may be
enough to indicate the general forms and proportions, and, instead of laboring
over details, which
may be often repeated in the same subject, to elaborate such details in bits
here and there-or
perhaps on a larger scale, at the foot of the sketch, or on another piece
of paper.  Instead of
drawing in with equal care and precision all the windows, doors, cornices,
etc., of a building, it
may be sufficient to mark their position and number, and to finish carefully
one of each.
  44. In sketching views, it very frequently occurs that we are obliged to
get in the genei ar
effect and composition on a scale so small that, when we come to its details,
it is almost impossible
to express them with the distinctness which may be desirable.  In such cases,
it is always better