IMPROVEMENTS. IN SAFETY LAMPS FOR MINES
Year: 1863

page_text: PROVISIONAL SPECIFICATION left by William Edward Gedge at the
Office of the Commissioners of Patents, with his Petition, on the 14th
September 1868.-A communication from abroad by François Chapuis
and Léonce Decombette, both of the Rue du Faubourg Saint Martin,
Paris, France.
I, WILLIAM EDWARD GEDGE, of the Firm of John Gedge and Son, of
No. 11, Wellington Street, Strand, in the County of Middlesex, Patent Agent,
do hereby declare the nature of the said Invention for "IMPROVEMENTS. IN
SAFETY LAMPS FOR MINES," (a communication to me from abroad by François
Chapuis and Léonce Decombette, both of the Rue du Faubourg Saint Martin,
Paris, France,) to be as follows:-
The improvements, the subject of this Invention, are applied to the
ordinary Davy lamp, with the object of causing the light to become extin-
guished in fire-damp, or, what comes to the same thing, in hydrogen even
mixed with air. The apparatus which it is proposed to add to the Davy lamp
is illustrated on the accompanying Sheet of Drawing forming part of this
Provisional Specification. Figure 1 represents a complete lamp; A, lamp;
G, G, G, G, G, the safety wire gauze cover, colored blue. Within the wire
gauze cover is screwed (above the lamp) an iron rod C, C, C, C, C, shaped
as shewn, Figures 1, 2, and 3, Figure 3 shewing the top of the rod, which is
of semicircular form. A disc B hinged to the end of a tube T, T, furnished
with a spring R, which tends to lower it, is fixed above the lamp, as shewn,
Figure 1, so that when lowered it extinguishes the flame F, taking its place,
that is to say, coming down on the wick holler. To put this lamp in working

page_text: order, the disc B must be raised (so that the flame may exist) and held in a
vertical direction, as at Figure 1, by means of a copper wire (or a wire of
other metal which will fuse more rapidly than iron) of smaller diameter than
the wire of the gauze cover G, G, G, G, G, passing over the hook H, from
thence into a groove at the back of the rod C, C, C, C, C, then forming the
cord of the semicircle, Figure 3, and finally attached at C". A notch C¹
serves to fix the end of the copper wire which is colored red in the Drawing.
The disc may be polished and act as a reflector, and a lens L hooked on
exteriorly to give more light. It is well known that when the fire-damp
arrives in a mine, its presence is made evident by the flame of all the lamps
turning blue, lengthening and licking the top of the wire gauze cover,
bringing it to a red heat, and shortly after to a state of fusion, upon which
explosions occur; and it will be readily understood, that if this phenomenon
occur in lamps constructed as above described and illustrated in the annexed
Drawing, the copper wire would be fused long before the wire gauze cover
would arrive at a red heat, and that the disc B would fall on the flame F and
extinguish it; the flame scarcely assumes a blueish appearance before it is
extinguished. This improved lamp may also be used as an alarm to signalize
the advance of the fire-damp before it reaches the miners in the following
manner-Suppose a lamp to be hooked to the vault of the gallery, the fire-
damp being lighter than the air occupies the upper region, and this lamp
would be extinguished before those held by the miners, but as they might
possibly not immediately observe the putting out of the light hanging above,
it is proposed to place at the bottom of the lamp an alarm, to be set in motion
by the fall of the disc B, which striking the rod I will release a bell catch,
and by means of an electric wire the same action may be made to commu-
nicate to the office that fire-damp has reached one of the galleries being
worked, so that assistance may be at once sent or proper precautions taken.