Of Copying
82. The two last-mentioned sources of excellence in the work
produced by machinery depend on a principle which pervades a very
large portion of all manufactures, and is one upon which the
cheapness of the articles produced seems greatly to depend. The
principle alluded to is that of copying, taken in its most
extensive sense. Almost unlimited pains are, in some instances,
bestowed on the original, from which a series o
copies is to be
produced; and the larger the number of these copies, the more
care and pains can the manufacturer afford to lavish upon the
original. It may thus happen, that the instrument or tool
actually producing the work, shall cost five or even ten thousand
times the price of each individual specimen of its power.
As the system of copying is of so much importance, and of
such extensive use in the arts, it will be convenient to classify
a considerable number of those processes in which it is employed.
The following enumeration however is not offered as a complete
list; and the explanations are restricted to the shortest
possible detail which is consistent with a due regard to making
the subject intelligible.
Operations of copying are effected under the following
circumstances:
by printing from cavities by stamping
by printing from surface by punching
by casting with elongation
by moulding with altered dimensions