AN IMPROVEMENT OR IMPROVEMENTS ON MACHINERY APPLICABLE TO THE IMITATION OF MEDALS, SCULPTURE, AND OTHER WORKS OF ART EXECUTED IN RELIEF
Year: 1832

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN BATE,
of the Poultry, in the City of London, Optician, send greeting.
WHEREAS His present Majesty King William the Fourth, by His Letters
Patent under the Great Seal of the United Kingdom of Great Britain and
Ireland, bearing date at Westminster, the Ninth day of April now last past,
did give and grant unto me, the said John Bate, His especial licence, full
power, sole privilege and authority, that I, the said John Bate, my executors,
administrators, and assigns, and such others as I, the said John Bate, my
executors, administrators, or assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term of years
therein expressed, should and lawfully might make, use, exercise, and vend,
within England, Wales, and the Town of Berwick-upon-Tweed, my Invention
of "AN IMPROVEMENT OR IMPROVEMENTS ON MACHINERY APPLICABLE TO THE
IMITATION OF MEDALS, SCULPTURE, AND OTHER WORKS OF ART EXECUTED IN
RELIEF;" in which said Letters Patent there is contained a proviso obliging
me, the said John Bate, by an instrument in writing under my hand and seal,
particularly to describe and ascertain the nature of my said Invention, and in
what manner the same is to be performed, and to cause the same to be
inrolled in His said Majesty's High Court of Chancery within six calendar

page_text: months next and immediately after the date of the said recited Letters
Patent, as in and by the same, reference being thereunto had, will more fully
appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Bate, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, is described and ascertained by
the Drawings hereunto annexed, and as follows, that is to say :-
Drawing 1, Figure 1, represents a side elevation of my improvement on
machinery applicable to the imitation of medals, sculpture, and other works of
art executed in relief. A, A, represents a fragment of a board or table, and
B shews a vertical section of a brass socket fixed thereto. C is a square brass
standard made to slide up and down within the socket, being very accurately
fitted. D is a steel screw, having a micrometer attached at its lower end, by
which means it can be turned so as to move the standard C at equal distances,
either ascending or descending. E shews a plate of metal fixed to the
standard C, and inclined to the horizontal plane of the table or board A, A, at
an angle of forty-five degrees. The upper edge of this plate has a groove
formed in it to receive two bevilled rollers of a carriage, now to be described.
F represents a carriage, which moves very freely on the plate E by means of
three rollers, two of which are bevilled so as to enter the groove formed to
receive them or the upper edge of the plate E. In this view only one of the
bevilled rollers a can be seen, the other being immediately behind it. These
rollers are made with long axes, and very accurately fitted in their bearings,
so as to move freely without shake. The lower part of this carriage is sup-
ported and moves on a single roller. b, the axis of which is placed at right
angles to those already described, the periphery revolving and resting upon
the ledge c. d, d, represents a sliding plate, which is made very true and
parallel on, two of its edges, and these are bevelled on each side so as to
produce a double prism. The champhered edges edges so formed enter the
grooves of four rollers fixed in the carriage F; two of these rollers are seen
near e, e, the other two being placed immediately behind cannot be seen in this
Figure. By these means the sliding plate d, d, is made to move very freely,
and yet with great accuracy. f represents a point fixed to the sliding plate
d, d; this is used to trace over any medal or any other suitable work of art
that is required to be copied. G shews a section of a portion of a sphere
rising from a plane surface, and similar to a medal in its general form. Any
such subject may be fixed to the supporting frame H by any suitable cement,
care being taken that its plane be placed in a proper position. I is a metal
guide fixed at its lower end to the sliding plate d, d; the upper portion of this

page_text: is formed into a straight edge at 9 and stands perpendicular to A, A.
K represents a vibrating lever, the arms of which are equal; this swings freely
on two conical points, one of which is seen in the arm L fixed upon the
carriage F. The upper end of the vibrating lever has a friction roller h
placed in it, which is always kept in contact with the straight edge of the
guide g, by the spring i, while the lower end of the lever moves the frame M,
at the end of which the diamond point is fixed, as shewn at j. perpendicular
to the surface of the copper plate N, which lies parallel with A, A. The
left-hand end of the point frame M is jointed on each side to the lower end
of the vibrating lever K, forming an elbow joint therewith, the pivots or
bearings being made conical, so as to avoid friction as much as possible.
p represents a small barrel fixed on an axis, one end of which turns in the
end of the arm q, and is retained in any position by friction. The other end
has a flat button formed on it by which it may be turned. r shews a small
silk cord; one end of this is coiled round the barrel p, and the other is attached
to the point frame M. By these means the diamond point may be raised
from the plate and kept suspended at pleasure. 0 represents a metal plate
fixed to the bracket p, which is firmly attached to the inclined plate E.
There are two such brackets, one is supposed to be removed, to shew the
parts that would otherwise be hidden. Q represents the plate carriage, which
has three friction rollers placed in frames under it. Two of these rollers are
bevelled and run in a groove formed in a plate O; the other roller is plain,
and rolls on the surface of the same metal plate. k is a steel chain, one end
attached to the arm R and the other, at 7, to a stud projecting from the under side
of the plate carriage Q. m shews a cord made fast at one end to the stud near
1, and passing over the pulley n, it hangs down and has the weight O appended
to it, by which means the carriage will be drawn along in the direction of the
dart, whenever C is lowered by the micrometer screw D. When this machine
is to be used, the micrometer screw D should be placed in the centre of its
range, as shewn at D in Figure 1, and then the medal or other object to be
traced over must be placed at such a height that the tracing point may be
brought just in contact with the centre of the medal or other object.
When the sliding plate d, d, is placed in the centre of the limits or rango
that it has to move in between the rollers that confine it, the centre of the
copper plate N must at the same time be placed immediately under the
diamond point with its edges parallel to the plate Q. The machine and plate
being thus adjusted, the micrometer screw D must be made to raise the
standard C, and all the parts combined therewith, until the tracing point f will
nearly reach the top of the medal or other subject G, at s. The tracing point

page_text: f.must then be laid hold of by the hand, and brought into contact with the
surface at s (moving the screw D as may be required, to bring the tracing
plate d, d, into its mean position) by means of the combined motions of d, d,
and F. The machine will then be in the proper position for beginning the
first line, when the button t must be turned, and the diamond point gently let
down upon the copper plate, and the tracing' point f being then passed
very carefully over that part of the medal which presents itself to it, the
diamond point will then be found to have etched a line on the copper plate
exactly corresponding to the undulations which the tracing point has passed
over on the medal. The diamond point must then be raised from the plate,
and the micrometer screw must be turned so as to produce such a space
between the lines on the copper plate as may have been previously determined
upon, and the same movements repeated, until the whole surface of the metal
has been traced over. When sculpture and other works of art are to be traced
over, and the undulations of the tracer transmitted to a plate so as to produce
a copy thereof, such works must be placed before the tracer f, in a vertical
position, and the mode of setting and adjusting the machine, and also the
copper plate, must be adopted as before described, and then if the tracer f be
made to pass over every part that the tracing point will reach, such undulations
will be transmitted to the copper plate, and a correct representation will be
the result. In some works that are executed in very high relief, it would be
quite impossible to reach many parts that are in deep recesses with a point of
the ordinary conical form, but for such purposes I have invented the following
instrument, which I call a tracing blade.
Figure 2 represents a side elevation of a tracing blade, combined with the
tracing plate, a fragment of which is shewn upon a larger scale at d, d. u, u,
represents the edge of the blade, which is exactly in a line with the axis v; this
axis is placed in a socket, where it turns freely, but without shake, being
secured therein by a screw and washer at the upper end. Tis a weight or
counterpoise that serves to balance the weight of the blade, which, it may be
seen, terminates in a point. When parts are to be traced that lay in deep
recesses, the point of this blade must be used for that purpose, the edge u, u,
being always brought in contact with those parts that are elevated, and when
the edge of the blade is in its passage sufficiently raised upon any projecting
part so as to give the point thereof a fair bearing, then the blade should be
gradually turned round as the point advances, so as to make it descend on the
opposite side of the projecting part of the same relative position as it assumed
when it was raised. In descending into any recess to trace the undulations
of deep-seated projections, the edge of the blade will be found of great use in

page_text: directing the point to such parts; and it should be observed, that whenever the
point of the blade has terminated its operation of tracing on the surface of any
projection, and begins to descend into any recess, that instant the diamond
point should be lifted, and kept suspended until the point of the blade comes
in contact with any other part of the surface over which it is to pass, and then
the diamond should be immediately let down upon the copper plate, by which
means the series of lines that produce the representation will be continued.
Figure 3 represents a front view of Figure 1, the same letters of reference
being placed upon the same parts wherever they can be seen. In this Figure
the standard C is omitted, and also the micrometer screw by which it is moved.
In former constructions the tracing point moved in a plane perpendicular to
the plane of the medal; now, in my construction, the tracing point moves in a
plane oblique to the plane of the medal, or, in other words, oblique to the
plane in which C moves. And the principle of my correction consists in
making the line described upon the copper (which is straight, so long as the
tracer describes the plane of the medal, and becomes diverted from the straight
line as the tracer rises above this plane), be diverted an equal quantity from
the straight line upon the copper, as the tracer is diverted from a plane per-
pendicular to the plane of the medal. The relative direction of the motions
required to produce this effect may be described by any right-angled triangle,
one motion being in the plane of the base, a second in the plane of the per-
pendicular, and a third in the plane of the hypothenuse, or in planes parallel to
the several planes respectively; and the proportion of apparent elevation in
the engraving will be to the elevation in the medal itself as the proportion of
the base of the triangle to its perpendicular.
In the triangle A, B, C, Figure 1, Drawing 2, the motion represented by
A, B, is effected in the machine by the edge g; that represented by A, C, is
effected by the sliding plate d, d; and the motion represented by B, C, is given
in the plane surface N. Also, in Figure 1, where the base and perpendicular
are equal, the engraving will appear as much elevated as in the medal itself.
In Figure 2, where the base is half the perpendicular, the engraving will
appear to have only half the elevation of the medal; and in Figure 3, where
the base is double the perpendicular, the engraving will appear to have double
the elevation of the medal. E, representing the medal; F, the plane of the
medal; and the triangles A, B, C, and m, n, o, being similar.
Figure 4 represents an impression from a plate which has been etched by
machinery of the usual description; the distortion of the features will be
evident upon a bare inspection. Figure 2 represents an impression from a plate
etched with my improved machine, the same subject having been used to trace

page_text: I over in both cases; a comparison of the two impressions will immediately shew
the superiority of the one produced by my improvements.
my
And I hereby declare, that whether the machinery or apparatus shewn in
the Drawing 1, Figure 1, at D and C, that is used to shift the tracing point
equal distances, moves either vertically, horizontally, or in any other direction,
Invention consists in making the tracing point move and operate upon
the medal or other work of art in a plane oblique to such motion, that being
the principle wherein my Invention differs from all other machinery now used
for producing similar effects. I also claim as my Invention the sole use of a
tracing blade of the description shewn in the Drawing 1, Figure 2, by the use
of which, when applied in the way I have described, sculpture or other works
of art executed in high relief, may be more advantageously traced over than
could be effected by any other instrument now in use for such a purpose.
In witness whereof, I, the said John Bate, have hereunto set my hand
and seal, this Ninth day of October, in the year of our Lord One
AND BE IT REMEMBERED, that on the same Ninth day of October,
in the year above mentioned, the aforesaid John Bate came before our Lord
the King in His Chancery, and acknowledged the Specification aforesaid, and
all and every thing therein contained, in form above written. And also the
Specification aforesaid was stamped according to the tenor of the Statute in
that case made and provided.
Inrolled the same Ninth day of October, in the year above written.