Mechanical Processes of Engraving. 447 
feea, ME. Vial, of Paris, read a paper before the So- 
ciety of Arts, “On a Method of Instantaneous (?) En- 
graving on Metal.” This was based on the well known 
fact that by plunging a piece of one kind of metal 
into a saline solution of some metal opposite in character, 
the solution becomes decomposed, and the metal in 
solution is at once deposited upon the other piece of 
metal. In this process the artist executes his drawing 
with a metallic ink, which enables it to be transferred by 
pressure to a metal of the required opposite character, on 
which it appears in relief. This relief was then increased 
by the action of acids, or by voltaic electricity, and the 
engraving in relief was completed. None of these 
processes, however, appear to have been successfully 
adopted. 
I now come to the most recently introduced and most 
successful of processes intended to take the place of wood 
engraving, the Graphotype. This was invented by a very 
talented American artist, Mr. De Witt Clinton Hitchcock. 
The hint from which this discovery sprung was, as is not 
uncommon, given accidentally. Desiring to correct an 
error in a wood drawing with white, and having none of 
that pigment handy, Mr. Hitchcock used the white enamel 
of a glazed visiting card. As he removed the compo- 
sition forming the enamel, he found that the ink on the 
surface protected the parts beneath them from the action 
of his brush, so that the letters were soon in bold relief. 
The possible application of such a simple discovery directly 
flashed into the artist’s mind, and he at once commenced 
experiments, from which sprang the graphotype. This 
process was taken up in New York, and carried on so 
successfully, that its inventor brought it over to England, 
and about twelve months ago a company (limited of course) 
was organised to work it. The process is a very simple 
one, and as it has not been fully described to you before 
I will hastily go through it. : 
An artificial tablet of smooth chalk is obtained by re- 
ducing the finest French chalk to powder, and mixing it 
with water to the consistence of cream, separating the parts 
that precipitate, and repeating the operation several times 
to ensure an impalpable powder, capable of forming by 
compression a smooth, uniform substance. This is spread 
evenly upona smooth, flat plate of zinc, over which a flat 
plate of steel, with a finely-polished surface, is laid above 
the chalk, which rests between the two metal plates. 
NEW SERIES.—VOL, I. OO 
