AN IMPROVED STAFF OR INSTRU- MENT TO BE USED TO ASCERTAIN THE IRREGULARITIES IN THE SURFACES OF MILLSTONES WITH A VIEW TO THEIR CORRECTION
Year: 1868

page_text: LETTERS PATENT to Potto Brown, of Houghton, and Bateman Brown,
of Huntingdon, for the Invention of "AN IMPROVED STAFF OR INSTRU-
MENT TO BE USED TO ASCERTAIN THE IRREGULARITIES IN THE SURFACES OF
MILLSTONES WITH A VIEW TO THEIR CORRECTION."
Sealed the 18th December 1868, and dated the 23rd June 1868.
PROVISIONAL SPECIFICATION left by the said Potto Brown and
Bateman Brown at the Office of the Commissioners of Patents, with
their Petition, on the 23rd June 1868.
We, POTTO BROWN, of Houghton, and BATEMAN BROWN, of Huntingdon,
do hereby declare the nature of the said Invention for "AN IMPROVED
STAFF OR INSTRUMENT TO BE USED TO ASCERTAIN THE IRREGULARITIES IN THE
SURFACES OF MILLSTONES WITH A VIEW TO THEIR
THEIR CORRECTION," to be as
follows:-
This Invention has for its object an improved staff or instrument to be
used to ascertain the inequalities in the surfaces of millstones with a
view to their correction. At the present time a single straightedge of

page_text: wood is used for this purpose; it has a thin coating of color given to
it, and it is then applied to the stone. The object of the workman in
applying the staff is to mark the high parts of the stone, but great care
and skill are required in producing a plane or true surface by the indi-
cations of this instrument as the staff will also color the low sides of the
stone, provided there is a hollow extending across the stone from side
to side.
Now according to our Invention in place of forming the staff as a
single straightedge so that it gauges the stone only in one straight line
across it we so form the staff as to gauge the stone simultaneously in
several lines so arranged that should the stone be low on any side the
staff may be sure to take a bearing on the high side only and be
prevented from falling into the hollows to color them. We prefer to
construct the staff of two parallel straightedges connected together by
a circle somewhat smaller in diameter than the stone; the whole is built
up of wood in such manner as to ensure it as far as possible against
warping, and the face which comes in contact with the stone is made of
mahogany. This face is wrought truly to form and is corrected from a
true metal surface as frequently as may be necessary.
When the instru-
ment is in use color is applied to the straightedge, or it may be to the
whole of its face, and the instrument is applied to the stone with one of
the straightedges on either side of the centre or eye. These edges (if
they alone be colored, as we prefer) communicate the color to the high
parts on which they may chance to bear; but should it so happen that
the highest parts are not beneath the edges then the ring sustains them
out of contact with the face of the stone. The form of the instrument
may be to some extent varied, but it will be observed that whereas the
staff heretofore employed is a straightedge taking its bearings along
one line only, our improved staff is in principle an extended skeleton
surface which however it may be applied takes its bearing on the high
side and high parts of the stone only. This skeleton surface or frame is
very portable and convenient in use, it is kept true without difficulty,
and is easily coated with color, advantages which a complete surface
would not have, and the absence of which renders a complete surface
inapplicable.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Potto Brown and Bateman Brown in the Great
Seal Patent Office on the 23rd December 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, POTTO
BROWN, of Houghton, and BATEMAN BROWN, of Huntingdon, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of June, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said Potto Brown and Bateman Brown, Her
special licence that we, the said Potto Brown and Bateman Brown, our
executors, administrators, and assigns, or such others, as we, the said
Potto Brown and Bateman Brown, our executors, administrators, and
assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "AN IMPROVED STAFF OR INSTRUMENT TO
BE USED TO ASCERTAIN THE IRREGULARITIES IN THE SURFACES OF MILLSTONES WITH
A VIEW TO THEIR CORRECTION," upon the condition (amongst others) that
we, the said Potto Brown and Bateman Brown, our executors or
administrators, by an instrument in writing under our or their hands
and scals, or under the hand and seal of one of us or them,
should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Bateman Brown, on behalf of
myself and the said Potto Brown, do hereby declare the nature of the
said Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement
thereof, that is to say:-
This Invention has for its object an improved staff or instrument to be
used to ascertain the inequalities in the surfaces of millstones with a

page_text: view to their correction. At the present time a single straightedge of
wood is used for this purpose; it has a thin coating of color given to
it and it is then applied to the stone. The object of the workman in
applying the staff is to mark the high parts of the stone, but great skill
and care are required in producing a plane or true surface by the indi-
cations of this instrument as the staff will also color the low sides of the
stone, provided there is a hollow extending across the stone from side
to side.
Now according to our Invention in place of forming the staff as a
single straightedge so that it gauges the stone only in one straight line
across it we so form the staff as to gauge the stone simultaneously in
several lines at the same time, and so arranged that should the stone be
low on any side the staff may be sure to take a bearing on the high side
only and be prevented from falling into the hollows to color them. We
prefer to construct the staff of two parallel straightedges connected
together by a circle somewhat smaller in diameter than the stone; the
whole is built up of wood in such manner as to ensure it as far as
possible against warping, and the face which comes in contact with the
stone is made of mahogany. This face is wrought truly to form, and is
corrected from a true metal surface as frequently as may be necessary.
When the instrument is in use color is applied to the straightedge, or it
may be to the whole of its face, and the instrument is applied to the stone
with one of the straightedges on either side of the centre or eye. These
edges (if they alone be colored, as we prefer) communicate the color to
the high parts on which they may chance to bear; but should it so
happen that the highest parts are not beneath the edges then the ring
sustains them out of contact with the face of the stone. The form of
the instrument may be to some extent varied, but it will be observed
that whereas the staff heretofore employed is a straightedge taking its
bearings along one side only, our improved staff is in principle an
extended skeleton surface which however it may be applied takes its
bearing on the high side and high parts of the stone only. This skeleton
surface or frame is very portable and convenient in use, it is kept true
without difficulty, and is easily coated with color, advantages which a
complete surface would not have, and the absence of which renders a
complete surface inapplicable.
In the Drawings hereunto annexed is shown a staff constructed in the
We nuafor for carrying out our Invention

page_text: Figure 1 is a face view of the staff, and Figure 2 a transverse section
of the same taken at the line A, B.
a, a, are two parallel straightedges, each composed of layers or
thicknesses of mahogany held together with screws, the object of so
constructing the straightedges being to avoid warping. The two straight-
edges are connected together by a circle 6 which is somewhat smaller
in diameter than the stone; this circle is also built up of layers of
mahogany held together by screws, each layer being composed of
numerous segments, as shown. The segments of one layer are also made
to break joint with the segments of the layer next to it so that the ring
may be of equal strength throughout..
At the points where the straightedges are connected to the circle both
the circle and the straightedges have notches cut into them, as shewn
at Figures 3 and 4, Figure 3 showing the form of the notch cut into the
circle, and Figure 4 the form of the notch cut in the straightedges. The
circle and straightedges with notches so cut into them are placed
together and attached one to the other by metal angle pieces c, c, as
shewn. The ends of the straightedges are also connected to one another
by wooden cross bars d, d, which serve as handles by which the staff
may be held when in use. When the staff has been put together as
above described the face of the straightedges and of the circle are by
the aid of a true metal surface reduced to an even plane, and this
plane surface is from time to time corrected as frequently as may be
necessary.
In witness whereof, I, the said Bateman Brown, have hereunto
set my hand and seal, this Eleventh day of December, in the
year of our Lord One thousand eight hundred and sixty-eight.