Dewsbury.
_Camera Lucida_ (Vol. viii., p. 271.).--With my camera lucida I received a
printed sheet of instructions, from which the following extract is made, in
answer to CARET:
"Those who cannot sketch comfortably, without perfect distinctness of
both the pencil and object, must observe, that the _stem_ should be
drawn out to the mark D, for all distant objects, and to the numbers 2,
3, 4, 5, &c. for objects that are at the distances of only 2, 3, 4, or
5 feet respectively, the stem being duly inclined according to a mark
placed at the bottom; but, after a little practice, such exactness is
wholly unnecessary. The farther the prism is removed from the paper,
that is, the longer the stem is drawn out, the larger the objects will
be represented in the drawing, and accordingly the less extensive the
view.
"The nearer the prism is to the paper, the smaller will be the objects,
and the more extensive the view comprised on the same piece of paper.
"If the drawing be two feet from the prism, and the paper only one
foot, the copy will be half the size of the original. If the drawing be
at one foot, and the paper three feet distant, the copy will be three
times as large as the original: and so for all other distances."