leave the building; so that only by a widespread plot could all these
safeguards be successfully eluded.

[Illustration: THE ENGRAVING-ROOM.]

The little party was now shown into a very long room, at one end of
which was ranged a row of compartments like sentry-boxes. In each of
these sat a silent engraver, bent over the small square of steel upon
which he was cutting some part of the design for paper money or stamps.
The plates from which the stamps were formerly printed are the property
of the government, so that the old designs, with a slight modification,
are still in use. This modification consists of a trefoil mark placed in
the upper corner of the new stamps, which will serve to distinguish them
from the old issues printed by the American Bank-note Company. The work
of the engravers is necessarily so painstaking and slow that the
original dies are considered too expensive to use in the
printing-presses. Thus, after the engraver has completed a die, it is
subjected to a hardening process, and the design multiplied indefinitely
upon soft steel plates by what is known as the transfer-press. The
children were shown a long row of these presses, as well as the great
vaults where all the designs, dies, and plates are locked up after the
day's work. From the silence of the engravers' department they were led
into the din and clatter of the press-room below. Here they found the
new steam-presses as well as old-fashioned hand-presses in operation,
and were able to see every detail of the actual printing of stamps.

[Illustration: TAKING SHEETS OFF THE PRESSES.]

The hand-presses are worked by a plate-printer and one assistant, the
printer first inking and polishing the engraved plate over a series of
small gas-jets, after which it is placed on the press. His assistant
now lays a dampened sheet of paper upon the plate, the printer gives the
press a turn, and a sheet of bright new stamps is drawn out at the other
side. This work is done quickly and accurately, but it is a very slow
process compared with that of the steam-presses, which turn out sheets
of four hundred stamps each at the rate of one hundred thousand stamps
an hour. The steam-presses carry four plates on an endless chain around
the sides of a large square, in the circuit of which the plates are
automatically heated to the proper temperature, inked, wiped off, and
printed. The blank paper is laid on the plates by one assistant, while a
second helper takes out