A NEW AND IMPROVED PRESSURE OR TEMPERATURE INDICATOR AND ALARM APPARATUS, TO BE EMPLOYED IN CON- NECTION WITH THE INTERIOR OF SHIPS, SUBTERRANEAN PASSAGES, COM- PARTMENTS, OR CAPACITIES
Year: 1875

page_text: LETTERS PATENT to Alan Charles Bagot, of Pembroke College,
Cambridge, for the Invention of "A NEW AND IMPROVED PRESSURE OR
TEMPERATURE INDICATOR AND ALARM APPARATUS, TO BE EMPLOYED IN CON-
NECTION WITH THE INTERIOR OF SHIPS, SUBTERRANEAN PASSAGES, COM-
PARTMENTS, OR CAPACITIES."
Sealed the 21st August 1875, and dated the 13th March 1875.
PROVISIONAL SPECIFICATION left by the said Alan Charles Bagot
at the Office of the Commissioners of Patents, with his Petition,
on the 13th March 1875.
I, ALAN CHARLES BAGOT, of Pembroke College, Cambridge, do
hereby declare the nature of my said Invention for "A NEW AND IMPROVED
PRESSURE OR TEMPERATURE INDICATOR AND ALARM APPARATUS, TO BE EMPLOYED IN
CONNECTION WITH THE INTERIOR OF SHIPS, SUBTERRANEAN PASSAGES, COMPART-
MENTS, OR CAPACITIES," to be as follows:
-
The Invention is designed for the purpose of enabling persons in
authority, or others, on board ship, coal pits, mines, warehouses, hotels,

page_text: dwelling houses, and the like, to ascertain or be warned of the stato of
pressure or heat of the atmosphere in any one or more compartments,
subterranean passages, capacitics, or confined spaces locally situated near
to or at a distance remote from the place where the indication, warning,
or alarm is given.
In order that the Invention may be clearly understood I will proceed
to describe as an example its application to the interior of a ship or
sailing vessel, at the same time remarking that the said description will
be equally applicable and similar in its arrangement and adaptation for
like purposes in warehouses, hotels, buildings, or coal pits.
The Invention as applied to vessels at sea may be thus described :—
I place in any one or more compartments, cabins, holds, or places about
the ship, or even intermixed with the cargo, ordinary metallic thermo-
meters and metallic ancroid barometers, a pair of cach in any one
or more of the said localities. Apart from these instruments and
conveniently situated in some other portion of the vessel I place a
"Leclanche" or other battery, and in the captain's cabin or other
special locality I fix an electrical indicator and bell or other alarm.
Tho indicator is provided with drop cards or movable discs which have
marked upon their surfaces, or otherwise expose when acted upon as
herein-after described, the names or numbers of the various compart-
ments and localities where the aforesaid thermometrical and ancroid
barometrical instruments are placed. One pole of the battery is always
in direct communication with the indicator and bell or other alarm
apparatus, and the other pole of the battery is similarly connected with a
fixed portion of each of the thermometrical and ancroid barometrical
instruments at a distance some little removed from the sensitive metallic
moter or moters of those instruments when in their normal state. Thus
it will be seen that when there is no undue pressure or heat in any ono
compartment, or more, of the vessel, the electric circuit with the battery
is incomplete or broken at the points separated by the termination of the
conducting wires from the battery, and the sensitive metallic moters of
the instruments before mentioned; but in the event of any one or more
of the compartments, spaces, or capacities in which the instruments are
placed becoming heated or surcharged with gas so as to assume an undue
presence of pressure, then and in such case the sensitive metallic moters
of the instruments would be acted upon by such heat or pressure, an

page_text: consequently advance in the direction of the wire communicating with
the battery, and so automatically close the electric circuit by making
contact with such wire.
Whether such contact be made by the thermometer and aneroid
barometer together, or by one only, the circuit or current would be closed
and effect instant and simultaneous action to the indicating and alarm
apparatus, shewing at once through the medium of the dropping printed
cards or tablets, or by the removal of the discs before mentioned the
exact locality or localities from whence the alarm was transmitted, thus
giving instant and positive direction where danger was developing or
assistance required.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alan Charles Bagot in the Great Scal Patent
Office on the 13th September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALAN
CHARLES BAGOT, of Pembroke College, Cambridge, send grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of March, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alan Charles Bagot, Her special
licence that I, the said Alan Charles Bagot, my executors, admini-
strators, and assigns, or such others as I, the said Alan Charles
Bagot, 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 Inven-
tion for "A NEW AND IMPROVED PRESSURE OR TEMPERATURE INDICATOR AND
ALARM APPARATUS, TO BE EMPLOYED IN CONNECTION WITH THE INTERIOR OF SHIPS,
SUBTERRANEAN PASSAGES, COMPARTMENTS, OR CAPACITIES," upon the condition
(amongst others) that I, the said Alan Charles Bagot, my executors or
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the

page_text: 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 Alan Charles Bagot, 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 and accompanying Drawings :-
The Invention is designed for the purpose of enabling persons in
authority, or others, on board ship, coal pits, or other mines, warehouses,
hotels, dwelling houses, conservatories, and the like, to ascertain or be
warned of the state or changes in the pressure or heat of the atmosphere,
or of the heat or temperature of mineral or vegetable produce stowed
away or contained in any one or more compartments, subterranean
passages, capacities, or confined spaces locally situated near to or at
a distance from the place where the indication warning or alarm is
given.
In carrying out my Invention I place a metallic thermometer and a
metallic barometer singly or in pairs, in any one or more compartments
of a dwelling house or other building, or in the subterrancan passages
or workings of a coal pit or other mine, or in the cabins or holds of
vessels, intermixed with the cargo or otherwise, or in contact with mineral
or vegetable produce, such as grain, hay, jute, cotton, coal, and the like,
whereever stowed or warehoused. In electrical connection with these
instruments and in a position convenient thereto, I place a "Leclanche "
or other battery, and again in some other special locality I fix an
electrical indicator and bell or other alarum or signal apparatus.
The indicator is provided with drop cards, movable discs or tablets,
which have marked upon their surfaces, or otherwise expose or signal
when acted upon as herein-after described, the names or numbers of the
various compartments and localities where the aforesaid thermometrical
and barometrical instruments are placed. One pole of the said battery
is always in direct communication with the indicator and bell, or other
alarum apparatus, and the other pole of such battery is similarly con-
nected with a fixed portion of each of the thermometric and barometric
instruments at an adjustable point some little distance removed on either

page_text: side from the sensitive metallic motor, of one or both of those instru-
ments when in their normal state, in which position the electrical circuit
is broken or incomplete, or as an equivalent may be maintained for the
purpose of being broken.
In order that the arrangement and action of the apparatus may be
well understood and explained in detail, I have hereunto annexed
diagram illustrations of the apparatus which, for example, are arranged
for indicating heat or pressure in any locality where such apparatus is
placed, whether on land or aboard ship.
In these explanatory diagrams, Fig. 1, A is a chamber or capacity,
which may be the compartment of a warehouse, dwelling house, or hotel,
the cabin or hold of a vessel, the subterranean working of a coal pit or
other mine; or any other place where it is desirable that the state of
the atmosphere or material contained in such place is required to be
automatically indicated. In any one or more of such chambers or
capacities I place a thermometric and a barometric instrument, singly or
in pairs, the construction or form of which I prefer to be similar to that
shewn at Figs. 2 and 3, in which it will be seen that the junction a with
the wire forming connection with one pole of the battery through
the medium of the indicating finger of the dial is fixed to the metallic
casing b, and the other sliding insulated junction c forming connection
with the other pole is provided with a projecting metallic finger o which
is arranged to move in a direction described by the circular traverse of
the indicating finger of the dial, so that its position thereon may be
adjusted to rest at any number indicating a certain degree of temperature
or pressure. At this determined point the projecting adjustable finger of
forms a metallic abutment, the space between which and the point of the
indicating hand or finger of the dial forms the break in the circuit of the
electric current, but so soon as such finger (which is actuated by the
sensitive motor of the instrument) is caused by change of temperature or
pressure to form contact with the adjustable projecting finger o, the
electric current is closed. At any desired and convenient distance from
these instruments I place the battery B, and removed from this again I
place an electrical indicator and bell or other alarum, by preference
similar to that shewn at C and D.
..
1
1 Ram and alamm

page_text: will best suit the circumstances in which the apparatus is to be employed.
It will thus be seen that so long as there is no undue pressure or heat in
any one or more of the localities or places where the instruments are
placed the electric circuit with the battery is broken or incomplete at the
points of separation formed on the dials of the instruments between the
sensitive metallic motors thereof and the adjustable sliding finger o
before mentioned, but in the event of any one or more of the compart-
ments, spaces, or capacities in which the instruments are placed becoming
heated or surcharged with gas so as to assume an undue presence of
pressure or heat, or the reverse, the sensitive metallic motors move the
indicating fingers of the dials in the direction of the metallic abutment o,
as the case may be, until contact therewith is effected, at which time the
electric circuit is closed or complete, and will be maintained so long as
the change continues, so that whether such contact is made by the
thermometer or barometer together, or by only one of such instruments,
the circuit would be equally closed and maintained synchronally with the
changed conditions of heat and of pressure, and cause instant and
simultaneous action in the indicating and alarum apparatus C, shewing
at once through the medium of the altered positions of the cards or lablls,
or exposed numbers 1, 2, 3, 4, on such apparatus, the exact locality or
localitics, and whether from pressure or heat, from whence the alarum
was transmitted, thus giving instant and positive indication where
danger was developing or assistance required.
I would further remark that the apparatus is applicable and equally
servicable as a means for indicating heat or pressure of gas produced by
chemical action arising from decomposition, spontaneous combustion, or
similar causes, as the heat so generated would produce the effect necessary
to put the metallic motor of the thermometer in action so as to close the
electric current or similarly close circuit in the barometer.
Having now described the nature of my said Invention, together with
the means of carrying the same into practical effect, I would wish it to
be distinctly understood in conclusion that I claim as of my Invention,
the novel and peculiar arrangement of apparatus in connection with a
"Leclanche" or other battery whereby I am enabled to break and close
or maintain the circuit of the electric current automatically through the
medium of the sensitive metallic motors of thermometric and barometric
instruments, when arranged in the manner and employed for the purpose

page_text: as herein-before substantially described, set forth, and fully illustrated in.
the Drawings annexed.
In witness whereof, I, the said Alan Oharles Bagot, have
hereunto set my hand and seal, this the 25th day of August, in
the year of our Lord One thousand eight hundred and seventy-
five.
ALAN CHARLES BAGOT. (L.S.)