of a properly graded modern series containing the
usual sizes. In fact, on account of the laws of optics, which cannot
be gone into here, only one size of a series is cut in absolutely
exact proportion to the patterns.

As it is impossible to describe these machines clearly without the aid
of many diagrams and much technical language, only a brief description
of their operation will be given.

When the letters are to be engraved in steel, blocks or "blanks" are
cut from soft steel and finished to the proper size. A blank is then
fastened in the "holder," the machine for cutting the letter in relief
adjusted to the proper leverage, and the pattern clamped to the "bed."
The long arm of the lever, containing the proper "tracer" or follower,
is moved by the operator around the outside of the pattern on the
copper-faced metal plate, causing the blank to be moved by the
shorter arm around and against a rotating cutting tool. This operation
is repeated several times with different sizes of tracers and
different adjustments to enable the cutting tool to cut at different
depths, until finally a steel letter in relief is produced, engraved
the reverse of the pattern and very much smaller. After being hardened
and polished, this is called a steel punch, and, when driven into a
flat piece of copper, it produces what is known as a "strike" or
unfinished matrix.

If in the same machine type metal is used for blanks, the resulting
originals are placed in a "flask," or holder, and submerged in a bath,
where they receive on the face of the letter a thick coating of
nickel, electrically deposited. As soon as the deposit is of
sufficient thickness, they are removed and the soft metal letters
withdrawn, leaving a deep facsimile impression in the deposited metal,
which also is an unfinished matrix.

The machine for engraving a matrix in intaglio is operated in much the
same manner as that for engraving a punch in relief. The same patterns
are used, but the operator traces on the inside of the raised outline
instead of on the outside. Besides following the outline, the operator
guides the tracers over all the surface of the pattern within the
outlines; otherwise the letter would appear in the matrix in outline
only. The matrices are cut in steel and in watchmakers' nickel, and
the work is so accurately done that about half the labor of finishing
is saved.

It will be noted from the foregoing that all three processes of
engraving end