to be available for engraving. To-day annealed steel is almost
exclusively used for this purpose. Annealed steel is steel which has
been softened without being decarbonized. The surface is carefully
ground and polished to a mirror-like brightness. Any work which is to be
reproduced many times, such as postage stamps and parts of bank-notes,
is made on small pies of steel called dies.

If the design to be used is in the shape of a drawing or engraving, a
sheet of gelatin may be laid over it and the outlines traced with a
sharp-pointed instrument. More often a photograph is taken on a
ferrotype plate and the outlines scratched into the plate. These
outlines are filled with vermilion. A piece of paper is then laid on the
plate and the two passed through a hand-press. This is called "pulling"
an impression. While the ink of the impression is still moist it is
sprinkled with powdered vermilion to strengthen the lines. The block of
steel is then covered with an etching ground (a composition of
asphaltum, wax, resin and ether) and the impression is transferred to
this. The outlines are cut through the etching ground and bitten into
the steel with acid. The coating is then removed from the block and the
artist proceeds with the engraving. The mechanical details and various
methods of engraving are highly interesting but time will not permit
their discussion.

An engraver is seldom expert in more than one style of work. Each makes
a specialty of some branch, portraiture, lettering, scroll-work, etc.
For this reason several engravers are usually employed on each die for a
postage stamp. And in this inability of one individual to do all styles
of work equally well lies one of the great securities against
counterfeiting.

In the course of making a die, proofs are usually taken and these are
much prized by collectors.

The die being finished, it is placed in a bath of cyanide of potassium
and heated until the vessel containing it is red hot. This process
occupies from fifteen minutes to half an hour for dies but may take as
much as an hour for a large plate. The die is then transferred to a bath
of oil, to cool and temper it. By this process it is thoroughly
hardened.

[Illustration: From "The Popular Science Monthly," Vol. XLVI, No. 5.
Copyright, 1895, by D. Appleton & Co.]

In the case of postage stamps, where it is desired to exactly duplicate
the design many times on a plate, recourse is had to transfer rolls. A
transf