IMPROVE- MENTS IN THE MEANS OF INDICATING THE PRESENCE OF FIRE-DAMP OR CHOKE-DAMP IN MINES, AND OF DISPERSING FIRE-DAMP, AND ALSO OF TELEGRAPHING IN MINES
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Frederic Newton Gisborne and
Henry Wickens at the Office of the Commissioners of Patents, with
their Petition, on the 8th March 1862.
We, FREDERIC NEWTON GISBORNE, of No. 3, Adelaide Place, London
Bridge, in the City of London, Engineer and Electrician, and HENRY
WICKENS, of No. 4, Tokenhouse Yard, Bank, in the City of London,
Gentleman, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE MEANS OF INDICATING THE PRESENCE OF FIRE-DAMP OR CHOKE-DAMP
IN MINES, AND OF DISPERSING FIRE-DAMP, AND ALSO OF TELEGRAPHING IN MINES,"
to be as follows:-
The fire-damp or carburetted bydrogen gas which is generated in a coal mine
is of less weight or specific gravity than the atmospheric air, and the choke-
damp or carbonic acid gas in a mine is of greater weight or specific gravity
than the atmospheric air, and our Invention consists in the employment in
combination with suitable apparatus of those relatively lesser or greater weights
to connect an electric circuit, and thereby cause the required indications or
signals to be given.
We will explain some of the modes in which we employ such weight. or
pressure for the above-mentioned purposes, but it will be obvious that we can
employ it in other modes as regards the details of the arrangements without
departing from the general principles of our said Invention. We suspend in
a glass vessel or chamber, which is open at one end, a delicately poised lever,
and we close the mouth of such vessel or chamber, and render it air-tight by
means of a double layer of very thin india-rubber strained over a ring, so as
to leave a clear space of about half an inch between the two layers, and we
insert a small stud of metal in the inner layer immediately over the upper end

page_text: of the lever, and a wire from the battery is passed through the side of the
vessel or chamber into the space between the two layers, so that the point
thereof may nearly touch the metal stud, and a wire is also passed through the
side of the vessel or chamber below the inner surface of the inner layer, and its
point brought nearly to the lower end of the lever, so that when the atmo-
spheric air in the vessel or chamber is expanded by the agency of lighter gases
the inner layer is pressed upwards, and the metal stud is brought into contact
with the wire between the layers, and the circuit is thus connected, and on
the other hand when the upper surfaces of the layers are deflected by the
agency of heavier gases thereon, the upper end of the lever is depressed, and
the lower end being thereby brought into contact with the wire in the chamber
the circuit is completed. We obtain the like results by means of the pressure
of the gases on a vacuum chamber similar to that in an aneroid barometer,
giving motion to a hand or indicator, and thereby connecting the circuit, and
in a similar way by a metallic barometer. We employ the like pressure
contact to connect an electric circuit through a Ruhmkorff coil and condenser,
and by causing the current to pass thence between two metal points placed in
vacuo in the interior of a glass bulb or chamber to illuminate such bulb or
chamber, and we employ the like pressure contact to connect an electric
circuit from a battery at the surface, and by an electro-magnet or galvano-
meter withdraw an opaque slide from the front or back of a colored bull's-eye
in a Davy lamp, and expose the colored light. We employ the drawal and
withdrawal of the said slide in a Davy lamp by the means mentioned, and also
the illumination of the bulb or chamber, for the purpose of telegraphing or
communicating signals from one part of a mine to another part thereof to and
from the interior of the mine from and to the surface or pit's mouth by
arbitrary signs; thus, for example, a continuous red light may be used to
signify "danger from fire-damp;" two movements may mean "send down the
cage," and so on, and in like manner one, two, or more flashes or illuminations
in vacuo may be used to signify pre-arranged sentences.
We also employ the pressure contact above mentioned to give signals by
releasing or moving an electro-magnet to sound an alarum, ignite an explosive
compound (at the surface of course) or otherwise indicate danger. The
fire-damp may be dispersed by firing it as it is generated by means of the
pressure contact completing the circuit and igniting some explosive compound.