IMPROVEMENTS IN RAT AND MICE TRAPS
Year: 1862

page_text: LETTERS PATENT to Harper Twelvetrees, of Bromley, in the County of
Middlesex, Manufacturer, for the Invention of "IMPROVEMENTS IN RAT
AND MICE TRAPS."
Sealed the 10th February 1863, and dated the 18th August 1862.
PROVISIONAL SPECIFICATION left by the said Harper Twelvetrees
at the Office of the Commissioners of Patents, with his Petition, on
the 18th August 1862.
I, HARPER TWELVETREES, of Bromley, in the County of Middlesex, Manu-
facturer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN RAT AND MICE TRAPS," to be as follows:-
My Invention consists of a long-shaped box made wholly or in part of wood,
zinc, tin, galvanized iron, wire, or other suitable material, that for mice being
about nine inches long by three and a half inches wide, and that for rats
about twenty-four inches long by eight inches wide. At one end of this box
is mounted a flat tin, iron, or wood board, termed a balance board, and upon
this is fixed a slanting or partially perpendicular plate extending from side to
side of the trap. Immediately above the centre of this balance board are two
holes cut in the sides of the trap, and so disposed that when the balance board
is not acted upon the partially perpendicular plate is in the same line as two
corresponding sides of the holes, and when a mouse or rat steps upon the

page_text: balance board and moves a little out of the centre thereof, as the end is
depressed with the weight of the animal, the slanting plate falls in a line with
the other sides of the entrance holes, thus preventing his return, and com-
pelling him to go forward into the body of the trap. Underneath the balance
board is fixed a plate of tin or iron extending between the two sides of the
trap, to prevent the vermin from making their escape in that direction. By
preference I allow the whole or a portion of the width of the entrance holes to
be left open across the top of the trap, so that the vermin may enter either at
the top or at the sides. I also form the entrance end of perforated zinc or
open wirework, and inside this end of the trap, upon the surfaces which can be
seen through the open worked end, I fix some corn, seeds, or other bait.
Inside the trap at the end of the balance board which falls down I dispose a
tin, iron, or zinc plate from side to side, and upon this plate I fix some small
hooks for attaching suitable food to act as a bait for the vermin, and thus, as
they are compelled to step upon the balance board to reach the bait, the
instant they move out of the centre the end falls down with their weight, and
finding they cannot return, owing to the slanting plate having closed the
entrance holes, they pass forward, and the same instant the balance board
returns to its original position. I prefer to form the greater part of the top of
the trap of an openwork zinc or wire plate, such plate being made to slide in
grooves. I also prefer to make the rat traps of galvanized iron, but they may
be made of any other suitable material. I further provide a piece of sponge
or other absorbing material to suspend upon one of the bait hooks after being
dipped in oil of rhodium.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Harper Twelvetrees in the Great Seal. Patent Office on
the 11th February 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HARPER
TWELVETREES, of Bromley, in the County of Middlesex, Manufacturer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of August, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Harper Twelvetrees, Her special licence that I, the said Harper
Twelvetrees, my executors, administrators, and assigns, or such others as I,

page_text: the said Harper Twelvetrees, my 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
"IMPROVEMENTS IN RAT AND MICE TRAPS," upon the condition (amongst
others) that I, the said Harper Twelvetrees, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their hands.
and seals, 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 Harper Twelvetrees, do hereby declare,
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the Sheet of Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
A rat or mouse trap according to my Invention consists of a long-shaped
box made wholly or in part of wood, zinc, tin, galvanized iron, wire, or other.
suitable material, that for mice being about nine inches long by three and
a half inches wide, and that for rats about 24 inches long by eight inches
wide. At one end of this box is mounted a flat tin, iron, or wood board,
termed a balance board, and upon this is fixed an inclined plate moving
beyond the vertical position in either direction, and extending from side to
side of the trap. Immediately above and coincident with the central balance
of this board are two holes cut in the sides of the trap, and so disposed that
when the balance board is not acted upon the raised inclined plate is, in the
same line as the two corresponding sides of the holes, and when a mouse or
rat enters upon the balance board and moves a little out of the centre thereof,
as the end is depressed with the weight of the animal, the slanting plate falls
in a line with the other sides of the entrance holes, thus preventing his return,
and compelling him to go forward into the body of the trap. Underneath the
balance board is fixed a plate of tin or iron extending between the two sides.
of the trap to prevent the vermin from making their escape in that direction..
By preference I allow the whole or a portion of the width of the entrance
holes to be left open across the top of the trap, so, that the vermin may enter.
either at the top or at the sides. I also form the entrance end of perforated
zinc or open wirework, and inside this end of the trap, upon the surfaces which;
can be seen through the openwork end, I fix some corn, seeds, or other. bait..

page_text: Inside the trap at the end of the balance board which falls down I dispose a
tin, iron, or zinc plate from side to side, and upon this plate I fix some small
hooks for attaching suitable food to act as bait for the vermin, and thus they
are compelled to step upon the balance board to reach the bait; the instant
they move out of the centre the end falls down with their weight, and finding
they cannot return, owing to the slanting plate having closed the entrance
holes, they pass forward, and the same instant the balance board returns to its
original position. I prefer to form the greater part of the top of the trap of
an openwork zinc or wire plate, such plate being made to slide in grooves. I
also prefer to make rat traps of galvanized iron, but they may be made of any
other suitable material. I further provide a piece of sponge or other absorbing
material to suspend upon one of the bait hooks after being dipped in oil of
shadium but other kinds of bait may be used

page_text: in that position affords easy access for, say, a mouse; so soon as the mouse enters
and its weight is fairly on the balance board, which it must be to reach the
bait, its weight causes the balance board to preponderate at that end, whereby
it and the flap k assume the position shown dotted. In this position the flap k
prevents any egress by the ingress aperture, as the mouse cannot remove his
weight from the balance board except by escaping under the hinged flap h,
which he naturally does, and is there securely trapped; the trap at same time
again sets itself for a repetition of the process, the balance board assuming its
original position, and so on.
Fig. 5 represents a side elevation, Fig. 6 a longitudinal vertical section,
Fig. 7 a plan, with the top removed, and Fig. 8 a transverse section on line
1, 2, Fig. 6, of a mouse or rat trap, being a modification of the foregoing,
according to my Invention. In this case the balance board p is equally balanced
on its fulcrum pin q, and remains down on whichever side it is depressed;
ingress to the trap by the vermin is had through openings r, r, in the sides.
On the balance board p there are side pieces s, s, erected, which close the
openings on that side of the balance board which is down, but leave it open
on the other for the ingress of the mouse or rat. Bait is applied at u in the
centre of the balance board, and it may also be placed in the perforated trays
or receptacles v, v, but which is difficult to get at through the perforations.
The mouse or rat in attempting to get at the bait u overbalances the board p
towards that side on which he is, thereby cutting off his retreat by the opening
at which he entered; on passing over the balance board it will again prepon-
derate on the opposite side, and so on it will oscillate as often as the animal
may cross over, and thus always cutting off its escape by the ingress aperture.
Failing in this, the animal will then try other means of escape, and will pass
under the hinged flap g of the partition h separating the ultimate receptacle f,
in which the vermin will be securely trapped, and leaving at same time
the trap in position to catch another rat or mouse, as the case may be, and
afterwards a third, and so on.
In the trap shown in Figs. 5. 6, 7, and 8 the ends are represented solid,
and with the sliding cover d passing from end to end. w is a catch for fast-
ening the cover d in position, but this may be variously arranged and made, as
also the other parts of the box or enclosure, without departing from my Inven-
tion. a, x, are pieces fixed on the bottom of the trap to prevent the vermin
lifting the flap h or balance board p.
Having described the nature of my Invention, and the manner of per-
forming the same, I declare that what I claim as my Invention, to be protected
by the herein-before in part recited Letters Patent, is, the arrangement and

page_text: combination of parts represented in the Drawings annexed, and herein-before
described, constituting and operating as apparatus, for entrapping or catching
rats and mice.
In witness whereof, I, the said Harper Twelvetrees, have hereunto set
my hand and seal, this Eleventh day of February, in the year. of our
Lord One thousand eight hundred and sixty-three.
HARPER TWELVETREES. (L.S.)