80

the present, to describe the main features
of it; so, if you will allow me to inter-
rupt for a moment the thread of my
story about the proof-sheet, which
comes next in order, I will give you this
description.

A great part of the entire press is
iron. The principle on which it acts, is
that of the lever. There is a great
pressure to be applied to the form; and,
of course, the’ object is to get the great-
cst amount of power, with the least ex-
pense of manual force. In old times,
when I was a little boy, they used to
employ a screw-press, as the best adapt-
ed for this purpose, But the lever, ad-
justed as it is in modern presses, is
much better than a screw. The press-
ure is given, by bringing forward that |
horizontal bar whieh you see somewhat |
above the middle of the press, measuring
from top to bottom. As this bar is
brought forward, the coils in the spiral
springs, which you notice on each side,
are brought nearer together ; the upright
bar, which is composed of two pieces,
one end of one serving as a socket for
one end of the other, and which, when
the press is not in motion, inclines a few
degrees horizontally, is brought into a
perpendicular position, and thus the im-
pression is made. As soon as this pro-
cess is effected, the pressman—so the
man is called whose business it is to do
this part of the work—gradually takes
off the pressure. If he should let go the
bar suddenly, such is the tendency of
the spiral springs; now in a forced posi-
tion, to get back as they were before,
that the bar would fly backward with
great force, and injure the press. So he
keeps hold of the bar, and lets it return
gradually.

THE YOUTH’S CABINET.

But I have not told you yet how the
sheet is placed upon the form, and how
the form gets in a position so as to re-
ceive the impression. On the right
hand of the press, you see two frames,
joined at the ends, the upper frame
reaching upward farther than any other
part of the press. The lower one is
called the tympan. The inside of the
frame is composed of cloth, with a sheet
of white paper pasted over it. The
pressman lays the sheet to be printed
on this tympan, and brings down the
upper frame, which he calls a frisket, and
which is connected with the tympan by
hinges, thus confining the sheet upon
the tympan. The frisket has also an-
other use. There are strips of paper
pasted across it, as you perceive. The
pressman has to arrange these strips of
paper differently for every new form that
is placed upon the press. They are de.
signed tocover the blank places between
the pages, so that when the form has
been supplied with ink, and the furniture
has received, as it must receive, more or
less of it, the paper, except where the
printing comes, can be kept clean.

The form lies below, on what is called
the bed of the press. The tympan is
connected with the bed by hinges; and
when the frisket has been brought
down upon the tympan, the two to-
gether are closed over the bed, which
contains the form to be printed. Just
below the bed, you see a crank. By
means of this, the bed, which is made
to run easily in grooves, is forced under
the horizontal plate of iron connected
with the spiral springs and the lever. This
iron plate, which has a perfectly smooth
Surface on its under side, and which

, Taust be large enough to cover the bed,