ted from electrotype plates in
the latter year. Many improvements in detail have been added since,
in the processes as well as the appliances. Robert Murray introduced
graphite as a coating for the form moulds. He first communicated his
discovery to the Royal Institution of London, and afterward received a
silver medal from the Society of Arts.

BLACKLEADING THE FORM.

The process of electrotyping is as follows: The form is locked up very
tightly, and is then coated with a surface of graphite, commonly known
as blacklead, but it is a misnomer. This is put on with a brush, and
may be done very evenly and speedily by a machine in which the brush
is reciprocated over the type by hand-wheel, crank, and pitman. A
soft brush and very finely powdered graphite are used; the superfluous
powder being removed, and the face of the type cleaned by the palm of
the hand.

TAKING THE MOULD.

A shallow pan, known as a moulding pan, is then filled with melted
yellow wax, making a smooth, even surface, which is blackleaded. The
pan is then secured to the head of the press, and the form placed on
the bed, which is then raised, delivering an impression of the type
upon the wax.

The pan is removed from the head of the press, placed on a table, and
then built up, as it is termed. This consists in running wax upon
the portions where large spaces occur between type, in order that
corresponding portions in the electrotype may not be touched by
the inking roller, or touched by the sagging down of the paper in
printing.

MAKING THE DEPOSIT.

The wax mould being built, is ready for blackleading, to give it a
conducting surface upon which the metal may be deposited in the bath,
superfluous blacklead being removed with a bellows. Blacklead, being
nearly pure carbon, is a poor conductor, and a part of the metal of
the pan is scraped clean, to form a place for the commencement of
the deposit. The back of the moulding is waxed, to prevent deposit of
copper thereon, and the face of the matrix is wetted to drive away
all films or bubbles of air which may otherwise be attached to the
blackleaded surface of the type.

The mould is then placed in the bath, containing a solution of
sulphate of copper, and is made a part of an electric circuit, in
which is also included the zinc element in the sulphuric-acid solution
in the other bath. A film of copper is deposited on the blacklead
surface of the mould; and when this shell is sufficiently th