The degree of excellence of the copy increases
in proportion as it is smaller than the original. The die of a
crown-piece will furnish by copy a very tolerable die for a
sixpence. But the chief use to be expected from this lathe is to
prepare all the coarser parts, and leave only the finer and more
expressive lines for the skill and genius of the artist.
151. Shoe-last making engine. An instrument not very unlike
in principle was proposed for the purpose of making shoe lasts. A
pattern last of a shoe for the right foot was placed in one part
of the apparatus, and when the machine was moved, two pieces of
wood, placed in another part which had been previously adjusted
by screws, were cut into lasts greater or less than the original,
as was desired; and although the pattern was for the right foot,
one of the lasts was for the left, an effect which was produced
by merely interposing a wheel which reversed the motion between
the two pieces of wood to be cut into lasts.
152. Engine for copying busts. Many years since, the late Mr
Watt amused himself with constructing an engine to produce copies
of busts or statues, either of the same size as the original, or
in a diminished proportion.
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