the subject.

The third method of producing an engraving from a drawing is by means of
what is known as the wax process. Drawings for this process should be
made on thin paper, for the following reasons: The process consists,
briefly stated, in coating a copper plate with a layer of wax about 1/32
inch deep, and in drawing upon the wax the lines to compose the
engraving, which lines are produced by means of tools that remove the
wax down to the surface of the copper.

The plate and wax are then placed in a battery and a deposit of copper
fills in the lines and surface of the wax, thus forming the engraving.
Now if the drawing is made on thin paper, the engraver coats the surface
of the drawing with a dry red pigment, and with a pointed instrument
traces over the lines of the drawing, which causes them to leave a red
imprint on the surface of the wax, and after the drawing is removed the
engraver cuts these imprinted lines in the wax. If the drawing is on
thick paper, this method of transferring the drawing to the wax cannot
be used, and the engraver may take a tracing from the drawing and
transfer from the tracing to the wax. It is obvious, also, that for wax
engravings the drawing should be made of the same size that the
engraving is required to be, or otherwise the tracing process described
cannot be used. Figure 297 represents an engraving made by the wax
process from a print from a wood engraving, and it is obvious that since
all the lines drawn on the wax sink down to the surface of the copper
plate, the shading is virtually composed of lines, the black surfaces
being where the lines have been sufficiently close together and broad to
remove all the wax enclosed within those surfaces.

[Illustration: Fig. 297.]

[Illustration: Fig. 298.]

The wax process is, however, more suitable for engravings in plain
outline only, and is especially excellent when the parts are small and
the lines fall close together; as, for example, in Figures 298 and 299,
which are engravings of a boiler drilling machine, and were produced
for the _American Machinist_ by tracing over a wood engraving from
London, "Engineering" in the manner already described. The fineness and
cleanness of the lines in the wax process is here well illustrated, the
disposition of the parts being easily seen from the engraving, and
easily followed in connection with the following description:

The machine consists of two horizontal bed-plates A 1 and A 2, m