Improvements in and Connected with Electric Lamps for Use for Lighting in Mines, Railway Carriages, and other Places, and Means for Indicating the Presence of Fire Damp or Explosive Gases in Mines or other Places.
Year: 1886

page_text: Date of Application, 11th Feb., 1886
Complete Specification Left, 11th Nov., 1886-Accepted, 28th Jan., 1887
Improvements in and Connected with Electric Lamps for Use for
Lighting in Mines, Railway Carriages, and other Places, and
Means for Indicating the Presence of Fire Damp or Explosive
Gases in Mines or other Places.
1 JOSEPH WILSON SWAN of Laureston Bromley in the County of Kent Gentleman
do hereby declare the nature of this Invention to be as follows :-
My Invention has for its principal object to provide means for the safe illumination
by electricity of coal mines gunpowder mills, petroleum stores railway carriages and
other places where a safe and portable light is required. It consists in the combination
with a portable primary or secondary battery of an incandescent electric lamp or lamps
and other appliances including if desired a fire damp indicator as hereinafter described
and giving great convenience in construction and freedom from danger of ignition of
When I employ a
combustibles, gases, or other materials by the lamp when in use.
secondary battery for the purposes of my Invention, I prefer to construct it in the
well known manner of a Planté battery or upon that principle, but preferably of a
cylindrical form with the peroxide or negative element in the centre and the lead or
positive element surrounding it and leaving an annular space between the two elements
for containing the Electrolyte. When I use a primary battery, I use the same arrange-
ment, but with a tube of Zine amalgamated with mercury instead of a tube of lead.
I prefer to form the body of the lantern or battery receptacle out of a Cylindrical or
other shaped block of ebonite, gutta-percba, wood, Earthenware, porcelain, glass or
other suitable material capable of holding and resisting the action of the Electrolyte,
and in the said block, I form, (by boring or moulding, according to the nature of the
material,) apertures, preferably of a Cylindrical form for the reception of the elements.
Or I may form the block of wood or other material, which of itself is not capable of
containing or resisting the action of the Electrolyte, and in that case I either render
the wood impervious to the action of the said electrolyte, (for example, by impregnating
it with paraffin wax,) or I line the compartments with a thin lining of Ebonite, India-
rubber, Gutta-percha, or other insulating compound, such for example, as Chatterton's
compound, marine glue or compounds of these with other substances in such a way as
to form a strong block with several liquid-tight compartments for containing the
Electrical elements. The numbers of the pairs of Elements combined together in series
in the body of the lantern may be varied, according to circumstances, but generally,
from two to eight, will be found most convenient. When the lamp or lantern is used

page_text: for a miner's lamp, I prefer to employ four pairs of elements, and to connect them
together by conducting lead wires, soldered or fused together, or pressed into contact
at their junctions by screws of ebonite or other non-conducting and noncorrodable
material, screwing into the block over and pressing upon the connecting wires,
where they intersect or are in juxtaposition.
wires down from the top of the body of the lantern to the bottom thereof, through
I also prefer to carry the terminal
holes or channels in it, and when employing a secondary battery, I prefer to form at
the bottom of the battery block or lantern body, metallic contact plates or sockets, to
facilitate the making of connection between the battery terminals and charging main.
The descending wires, in any case, serve for the attachments of branch wires for
enabling the switch and lamp to be joined in the circuit, in such a manner that the
said branch wires are not exposed to the action of the Electrolyte. Preferably, I
attach the Electric lamp to the side of the battery block, and cover it with a strong
cap of glass.
I provide a switch, by means of which the current from the battery may be turned
on or off the lamp and to protect the button or handle of this switch I embed or
countersink it partially or wholly in the body of the lantern. When the lamp is to
be used for the lighting of Railway carriages or the like I may provide it with a
fastening to enable it to be secured in position. When a
I prevent the spilling of the electrolyte out of the cells during transport or by
secondary battery is used
upsetting by covering or plugging the vent holes of each cell after charging I do
this either by means of separate plugs of India rubber or ebonite or equivalent
material or I close the apertures simultaneously by means of a disc of India rubber
pressed down by the lid of the-lantern or by plugs attached to to a plug plate which
when the lid is screwed on or otherwise fastened will hold down the plugs upon the
vent holes.
The body of the lantern is provided with a lid of ebonite or other suitable material
which screws on or is otherwise attached to it and serves to cover the cells and also
where necessary serves for the attachment of the handle by means of which the
lantern is carried. Where the lamp is used in coal mining and it is desired to
indicate the presence of fire damp I combine therewith a fire damp indicator which
may be constructed on the principle of what is well known as Leveing's fire damp
indicator in which two platinum wires are employed the one enclosed in a normal
atmosphere of air and the other exposed to the variable atmosphere of a mine, these
two wires being heated by the passago of an electric current in such a way that if
fire damp be not present the exposed and covered wires are heated and become
luminous to an equal degree but if fire damp be present in appreciable proportion
the exposed wire becomes hotter and the difference in degree of illumination is an
index to the proportion of fire damp in the atmosphere surrounding the lamp or
lantern. Where I adopt this principle I prefer to construct the indicator as follows.
The two indicating wires are enclosed in two adjacent chambers the one open and
the other closed. The open one is a glass tube fitted at each end with a metallic
casing tube cemented to the glass. The casing tubes nearly meet on the glass tube
their ends are contracted and extend beyond the ends of the glass. A diaphragm of
wire gauze is fitted within each casing tube and rests upon the end of the glass tube.
The indicating wire is fixed in the axis of the glass tube by cross wires resting on
the ends of the glass tube. A portion of the casing tubes are cut away to allow the
indicating wire to be seen. The closed chamber is constructed like the open chamber
except that the indicating wire is contained within a hermetically sealed tube through
the ends of which the terminals protrude. This is placed in the axis of the chamber
and the terminals of the indicating wire are connected respectively to the encasing
tubes. The electrical circuit is formed by connecting one of the encasing tubes of
the open chamber and one of the incasing tubes of the closed chamber together by
a metallic pole plate to which they are soldered the other ends of the incasing tubes
being attached to separate sole plates. One of these goes to the switch and thence
to one of the terminals of the battery and the other goes to the other terminal of
the battery.

page_text: In order to prevent danger of the gases in the mine being ignited by the heat of
the wire of the indicator which produces the combustion I have devised a special
indicator in which the said wire is not in communication with the atmosphere of the
mine whilst being heated by the electric current. In a transparent chamber I enclose
the wire and connect it to the electric circuit. The said chamber is normally open
for the entry thereinto or passage therethrough of the atmosphere of the place where
it is situated and the electric circuit is normally broken but I arrange an eccentric
button or other suitable device in such-wiso that it closes the passage or passages
giving communication with the atmosphere and afterwards makes contact for
completing the electric circuit through the wire the initial degree of heating of
which beyond that maintained after a few seconds closure of the circuit will indicate
the proportion of combustible gas in the portion of the surrounding atmosphere which
was enclosed in the chamber when the passage or passages thereinto was or were
closed. Wire gauze may cover the said passage or passages as a precaution if desired
in case by any accident the electric current be passed through the wire before the
chamber is closed. Any suitable relief device may be provided to compensate for
an explosion that may occur in the chamber. I may modify this arrangement by
providing in addition to the transparent chamber above described a second transparent
chamber permanently closed and containing ordinary atmospheric air and a wire
similar to that contained in the first named chamber for the purpose of comparison.
The above described indicator may be employed in conjunction with a voltaic
battery or other source of electricity separately from or combined with the electric
safety lamp.
Where accurate measurements of the proportion of fire damp present in the
atmosphere of a coal mine are required I combine with the lamp an apparatus which
indicates on a principle different from that herein before described the presence of fire
damp. The principle upon which this fire damp indicator acts is as follows:-A
portion of the air to be tested is burnt by the action of a hot platinium in a closed
vessel and the amount of shrinkage which ensures as indicated on a gauge tube is
the measure of the proportion of fire damp present. I construct this apparatus of
two adjacent tubes the one being the combustion tube and the other the gauge
protector tube. The combustion tube contains a platinium wire which can be included
in the battery circuit (so as to cause it to become red hot) by the action of a switch.
It is open at both ends and may or may not also contain diaphragms of wire gauze
within the end openings of the tube. It is connected with the adjacent gange
protector tube by the gauge tube which branches from the combustion tube and
passes through and goes to near the bottom of the gauge protector tube. Opposite
each of the openings of the combustion tube there is a plug or valve which opens or
closes automatically by the action of revolving or pressing the switch button. Except
when a test is being made the valves are open and therefore the air within the
combustion tube is the same as that outside. To make a test the switch button is
turned on its axis until the valves close and until at a point slightly beyond that of
complete closure of the valves the electric circuit is completed and the wire becomes
red hot. The switch is retained in this position until combustion is complete and
then the button is released and by the action of a spring on its axle it is slightly
brought backward towards its original position. The electric circuit is thus broken
and the valves remain closed and they are allowed to remain closed until the tube has
cooled and until after the alteration in the position of the liquid in the gauge tube has
been read off. Then the button is turned so as to reopen the valves and they remain
open until another test is to be made. It may sometimes be more convenient to have
the valve opening and closing mechanism separately from the switch which opens and
closes the electric circuit in which the combustion wire is included.

page_text: Improvements in and Connected with Electric Lamps for Use for
Lighting in Mines, Railway Carriages, and other Places, and
Means for Indicating the Presence of Fire Damp or Explosive
Gases in Mines or other Places.
1 JOSEPH WILSON SWAN of Laureston Bromley in the County of Kent Gentleman
do hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
My Invention has for its principal object to provide means for the safe illumination
by electricity of coal mines, gunpowder mills, petroleum stores, Railway Carriages
and other places where a safe and portable light is required. According to my
Invention employ a group or battery of primary or secondary cells and an
incandescent electric light giving portion constructed or arranged and combined as
hereinafter described whereby I obtain great convenience in construction and freedom
from danger of ignition of combustible gases or other materials by the lamp when in
use. There is also included as part of my Invention and combined with the lamp if
desired an indicator of fire damp or the like as hereinafter described.
Figure 1 of the accompanying drawings is a vertical section of one form of lamp
constructed according to my Invention. Figure 2 is a side elevation, Figure 3 is a
plan with the lid or cover removed, Figure 4 is a transverse section (on the line 12
figure 2) and figure 5 is a section of a part of the lamp shewing the plan of one form
of an indicator of fire damp or the like as hereinafter described. When 1 employ
secondary cells for the purposes of my Invention I prefer to construct them in the
well known manner of the Planté cell, or upon that principle, with the peroxide or
negative element a in the centre of and surrounded by the lead or positive element b
leaving an annular space c between the two elements for containing the electrolyte.
When I employ primary cells I use the same arrangement but instead of lead for the
positive element I use zinc amalgamated with mercury.
I prefer to form the body of the lamp out of a block D of ebonite, gutta-percha,
earthenware, porcelain, glass, or other suitable material, capable of holding and
resisting the action of the electrolyte and in the said block D I form (by boring, or
moulding, according to the nature of the material, and the form of the lamp)
apertures constituting cells for the reception of the elements and electrolyte. Or the
block may be formed of wood or other material which of itself is not capable of
containing or resisting the action of the electrolyte and in that case either render
the wood impervious to the action of the said electrolyte (for example by impregnating
it with paraffin wax) or I line the compartments with a thin lining of ebonite india
rubber, gutta-percha, or other insulating compound such for example as Chatterton's
compound, marine glue, or compounds of these with other substances, in such a way
as to form a strong block with liquid tight compartments for containing the elements
and electrolyte. The cells are covered at the upper part by a disc of ebonite or
other suitable material with a vent hole therein this disc being securely held in

page_text: place which may be effected by cementing it in with Chatterton's compound or in any
other suitable way. The number of the couples in series in the body of the lamp may
be varied according to circumstances but generally from two to eight will be found
most convenient. When the lamp is used as a miner's lamp I generally employ four
couples and connect them together by conducting wires (or their equivalents)
soldered or fused together or pressed into contact at their junctions by screws f of an
incorrodable material screwing into the block D and pressing upon the connecting
wires where they overlap or are in juxtaposition (see figure 3). I also prefer when
employing a secondary battery to carry the terminal conductors down from the top
of the body of the lamp to the bottom thereof through holes or channels in it (see 3.
Figure 4) and to form at the bottom of the lantern body metallic contact plates or
sockets (preferably of platinum) in connection with these wires to facilitate the making
of connection between the battery terminals and the charging main. The descending
conductors in any case serve for the attachments of branch conductors for enabling
the switch G and the bulb or illuminating portion of the lamp to be joined in the
circuit in such a manner that the said branch conductors are not exposed to the action
of the electrolyte 1 hold the bulb or illuminating portion H in spring clips h' as shewn
and cover it with a strong cap of glass.
1 provide a switch G by means of which the electric circuit may be completed or
interrupted so as to produce or extinguish the light and I prefer to protect the button
or handle of this switch by embedding or countersinking it partially or wholly in the
body of the lamp as shown clearly in figure 4. It may be retained in position by any
suitable catch or other means. I prevent the spilling of the electrolyte by covering
or plugging the vent holes of the cells after charging. I do this either by means of
separate plugs of India rubber or ebonite or equivalent material for each vent hole or
I close all the apertures as shewn in figure 6 by means of one disc of In lia rubber !
or equivalent material pressed down by the cap or lid Dan the screwed rod and
nut the said rod i carrying the eye for the handle; or I may effect the closure by
pieces of India rubber I attached to a plate 12 wich when the lid is screwed on will
hold down the pieces I upon the vent holes as shewn in Figure 1. This Figure shews
a modification in the form of handle.
Figure 7 is an elevation of a modification of lamp constructed according to my
Invention in which the light giving portion is on the top instead of on the side.
Figure 8 is a plan of the upper end of the lamp with the top portion removed and
Figure 9 is a side elevation of the said top portion Figures 10 and 11 are a cross
section and plan respectively of the elastic closing pad I used for closing the cells.
In this modification the light giving portion H is carried upon the ebonite cover D².
which corresponds in size to the top of the body part 1 of the lamp. The conductors
which proceed from the spring clips which hold the bulb pass through the cover D²
so that when the disc is placed on the end of the case or body part Dan presse i
down contact with the terminals of the battery is made by the upper en is of the
wires (to which the connections of the cells are led) entering the recesses at c and
making metallic contact with the wires c. The disc I of India rubber forms simple
and efficient means of automatically breaking this contact when required to extinguish
the lamp. This india rubber disc I I prefer to make with pieces at i to close
firmly the tops of the cells and a piece at to surround the boss d on the part D
which boss enters a recess in the centre of the top of the body part D as shewn in
Figure 7. The india rubber I not only forms a closure for the battery cells but by its
resiliency serves as a spring to break the contacts between 3 and so that the light
is not produced until the disc 1 is forced down so as to compress the in lia rubber an!
force the terminals f³ of the battery into contact with the plates of the terminals ²
of the lamp and so light the lamp. A convenient way of forcing the disc I downwards
is to provide a dise G at the opposite end or bottom of the case Dan 1 furnished with
screw passing axially through the body part D and engaging in a nut formed in the
boss dot the cover D above. The lamp is provided with a handle by which it can
be carried or suspended and this may be arranged by being centered at so that th
amp may be carried or supported with the light giving portion either above or below.

page_text: The terminals from the battery being connected to the wires (which pass through
from end to end of the body of the lamp on each side thereof) contacts with the
Baid wires can be made at each end of the lamp the one set for contact with the
terminals of the lamp filament as aforesaid and the other set being in openings as at
to make contact with the terminals of the charging dynamo by simply placing the
battery of the lamp upon a plate or table through which the terminals from the
dynamo pass.
For this purpose the disc Gamay have openings in it as at g which can be made
to coincide with the openings at when the battery is to be charged but at other
times are turned away therefrom so that the openings are covered by the disc G.
J is a strap by which the lamp can be slung over the shoulders of the miner.
The bulb is also here shewn as being held between spring clips which make
contact with the terminals protruding from the bulb but I do not necessarily limit
myself to any particular make or arrangement of bulb and attachments in either of
the forms of lamp herein described.
The cell connecting wires are in all the arrangements preferably protected from
corrosion by covering them with caoutchouc tubing and they are embedded in the
body part of the apparatus and where embedded they may be surrounded with
Chatterton's compound or some analogous and resisting material.
The cover or lid D2 may be of ebonite or other suitable material and may be screwed
on or be otherwise attached to the lamp. Figure 12 represents in elevation Figure 13
in plan and Fig. 14 in cross section a square form of lamp constructed according to
my invention there being in it two cells. The fastening for the lid D² is here shewn
as consisting of a strap, 8 passing around the lamp body Dand having a cross piece 8
extending over the lid D through a screw hole in which strap a screw is passed to
press upon the lid 13 and force it down so as to securely close the cells by squeezing
the india rubber pad I substantially as herein before described, the handle is shewn as
an ordinary loop passed through an eye at the top of the screw . The cross piece 8ª
instead of being made with a strap extending around the lamp body may have turned
down ends 8 with claws or projections 8 at the extremities engaging under lugs or
ribs at the top of the lamp body D as shewn in Figure 15. In these square lamps I
do not limit myself to the use of two cells.
When the lamp is used in places where it is desired to indicate the presence of fire
damp or like explosive gases I combine therewith an indicator which may be constructed
on the principle of what is well known as Liveings fire damp indicator in which two
platinum wires are employed the one enclosed in a normal atmosphere of air and the
other exposed to the variable atmosphere of a mine or other place, these two wires
being heated by the passage of an electric current in such a way that if fire damp or
other gases be not present the exposed and covered wires are heated and become
luminous to an equal degree but if fire damp or the like be present in appreciable
proportion the exposed wire becomes hotter and the difference in degree of illumination
of the two wires is an index to the proportion of fire damp in the atmosphere
surrounding the lamp. Where I adopt this principle I prefer to construct the indicator
as follows and as shewn at K in Figures 2 and 5 attached to the lamp. The two
indicating wires x and y are inclosed in two adjacent chambers the one open and the
other closed. The open one is a glass tube / fitted at each end with a metallic casing
tube m cemented to the glass. The casing tubes m nearly meet on the glass tube,
their ends are contracted and perforated and extend beyond the ends of the glass l. A
diaphragm n of wire guaze is fitted within each casing tube m and rests upon or
against either end of the glass tube /. The indicating wire is fixed in the axis of the
glass tube by cross wires p resting on the ends the glass tube / and in electrical
connection with the tubes m respectively. A portion of the casing tube is cut away as
shewn in Figure 2 to allow the indicating wire to be seen. The closed chamber is
constructed like the open chamber except that the indicating wire y is contained
within a hermetically sealed tube q through the ends of which the terminals protrude.
This tube q is placed in the axis of the chamber and the terminals of the indicating
wire y are connected respectively to the encasing tubes or caps m². The electrical

page_text: circuit is formed by connecting one of the encasing tubes m of the open chamber and
one of the encasing tubes m² of the closed chamber together by a metallic plate m³ to
which they are electrically connected by solder or otherwise the other of the encasing
tubes be attached to separate metal plates m one of these plates is connected
electrically with the switch and thence to one of the terminals of the battery and the
other plate is electrically connected to the other terminal of the battery.
In order to prevent danger of the gases in the mine being ignite by the heat of the
wire of the indicator which produces the combustion I have devised a special indicator
in which the said wire is not in communication with the atmosphere of the mine
whilst being heated by the electric current. In a transparent chamber I enclose the
wire and connect it to the electric circuit. The said chamber is normally open for the
entry there-into or passage there-through of the atmosphere of the place where it is
situated and the electric circuit is normally broken but I arrange an eccentric button
or other suitable device in such-wise that it closes the passage or passages giving
communication with the atmosphere and afterwards makes contact for completing the
electric circuit through the wire the initial degree of heating of which beyond that
maintained after a few seconds closure of the circuit will indicate the proportion of
combustible gas in the portion of the surrounding atmosphere which was enclosed in
the chamber when the passage or passages there into was or were closed.
may cover the said passage or passages as a precaution if desired in case by any
accident the electric current be passed through the wire before the chamber is close I.
I may modify this arrangement by providing in addition to the transparent chamber
above described a second transparent chamber permanently closed and containing
ordinary atmospheric air and a wire similar to that contained in the first named
chamber for the purpose of comparison as described with reference to Figures 2 and 5.
The above described indicator may be employed in conjunction with a voltaic
battery or other source of electricity separately from or combined with the electric
safety lamp.
Wire guaze
Where more accurate measurements of the proportion of fire damp or like gas
present in the atmosphere of a coal mine or other place are required I use an apparatus
which indicates, on a principle different from that hereinbefore described, the
presence of fire-damp or like gas. The principle upon which this indicator acts
is as follows: A portion of the air to be tested is burnt by the action of a hot
platinum wire in a closed vessel, and the amount of shrinkage which ensues is the
measure of the proportion of fire-damp present and is indicated on
a gange
tube. Figures 16 to 20 illustrate a construction of indicator which will serve
to explain the several modifications hereinbefore described. Figure 16 being a
front view, Figure 17 a Section through the combustion tube. Figure 18 a Section
through the gauge tube. Figure 19 a plan and Figure 20 an elevation of the
combustion tube alone with the valves open. The particular modification which I
have selected for illustration in these Figures is that in which a gauge tube is used
in combination with a combustion tube, from which however the construction of the
indicator, having a closable combustion tube as already described will be readily
understood. I construct the apparatus shewn in the aforesaid Figures of two adjacent
glass tubes with metal end tubes or cap-pieces m and m³, as described with regard to
the first arrangement, the one being the combustion tube and the other the tube
which encloses the gauge. The combustion tube contains a platinum wire which
can be included in the battery circuit, (so as to cause it to become red hot,) by the
action of a switch the contact pieces of which are represented at rº, s. This wire is
connected to the cross-wires, with which the metal tubes or caps m, are in contact,
as in the first described arrangement. The tubes or caps m are open at m³ and may
or may not also contain diaphragms n of wire gauze within the openings of the
tubes m.
The interior of the combustion tube is connected with the adjacent gauge
enclosing tube by the tube which branches from the combustion tube and passes
through and goes to near the bottom of the gauge-enclosing tube where its end is
open and dips into liquid at u. Opposite each of the openings m³ of the combustion
tube, there is a plug or valve v both of which open or close simultaneously by the
X,

page_text: action of an excentric w, on the revolving axis, w², by which the switch is also operated,
the said axis having an arm to, which presses the contact-piece r, against the contact
pieces. Except when a test is being made, the valves are open, being pressed open
by the springs and therefore the air from outside passes freely to within the
combustion tube. The excentric w, acts on one side or end against one of the valves v,
and on the other against the strap 3, which passes around the apparatus, and supports
the other valve v. To make a test, the axis of the switch is turned, until the
valves, are closed by the eccentric w as shewn in Figures 16 and 17, and until at a
point slightly beyond that of complete closure of the valves e, the contacts ŕ and s, are
pressed together and the electric circuit is completed, and the wire r, becomes red hot.
The switch is retained in this position during combustion, and when this has been
completely or sufficiently effected, the switch is released, and is brought slightly
backward towards its normal position. The Electric circuit is thus broken by the
contacts and separating, but the valves v, remain closed, and they are allowed to
remain closed until the combustion tube has cooled and until after the alteration in
the position of the liquid in the gauge tube has been read off. Then the axis w² is
turned so as to reopen the valves v, and they remain open until another test is to be
made. Figures 21, 22 and 23 are diagrams, shewing clearly how the before mentioned
operations are performed. Figure 21 shews the position when the valves are open
and the Electric circuit is broken. Figure 22 shews the position when the valves are
shut but the switch does not complete the Electric circuit, and Figure 23 shews the
position when the valves are shut and the electric circuit is completed. It may
sometimes be more convenient to have the valve opening and closing mechanism
separately from the switch which opens and closes the electric circuit in which the
combustion wire is included.
I may connect the indicator by flexible conducting connections to the battery so as
to allow of the indicator being conveniently swept along the top of the working or
other place in searching for explosive gas.
According to a modification of the indicator, Figures 16 to 20, I make the
combustion tube and the gauge tube of one piece of glass so as to simplify construction
and prevent leakage. In this modification, I arrange the combustion tube over the
gauge tube with the axis of the two tubes coincident. An arrangement on this plan
is shewn in Figure 24, in which the parts which correspond with those shewn in
figures 16 to 20 are marked with the same letters of reference; the parts 12 and t are all
made in one, the part being the combustion tube and that below being the gauge tube.
1, 1, is the base made to the curve of the lamp body, 2, 2, is a tube secured to the
base, 3, 3, is also a tube with its lower extremity closed, and also secured to the
base. The valve is constituted by the cap » having a rim of which is pushed down by
the cam w, actuated by the handle w². The upper portion of the cap is perforated
by holes, as at (say 12 of 1" diameter each). A spiral spring v³ tends to push the
valve open, when the pressure brought to bear by the cam to is removed. A washer
of India-rubber is cemented into the cap to ensure a tight closure. The glass tube !,
has a hole, (say about 6th inch diameter) at 4, and one, (say about th or 7th inch
diameter) at 5. The platinum wire spiral a, may be fitted into the tube 12 in a similar
manner to that hereinafter described, and the current may be turned on in the manner,
(by the turning of the handle w²) described with reference to figures 16 to 23.
may make the indicator of T form, as shewn in vertical Section in Figure 25, and in
cro Section in Figure 26, the combustion tube being in the position of the top line
of the T, and the gauge tube in that of the upright line of the T. In this case,
make the combustion tube and the gauge tube %, either of one piece of glass, or
partly of glass, and partly of metal. As shewn in the drawing the tube l² is of metal,
with which is cast an enclosure 13 for the tube l, which enclosure 13 has a slot for seeing
the indications of the gauge. In this form of the apparatus I may have either one or
both ends of the combustion tube 12 to open and shut and the opening and shutting
may be effected either by a valve or by valves similar to those described with reference
to Figures 16 to 20, or by means of a stop-cock or stop-cocks v, as illustrated in this
modification in which I shew openings and stop-cocks at both ends.
I

page_text: To facilitate the measurement of both small and large quantities of gas I may make
the lower part of the gauge tube of a smaller bore than the upper part as shewn in
Figure 25 and to render the level of the liquid in the gauge tube more easily visible,
I may back it or the tube which encloses it with white enamel. I sometimes make
the level of the column of indicating liquid adjustable for the purpose of bringing the
level of the liquid to the zero of the scale which I can accomplish by making a part of
the container capable of being moved relatively to the other part such as by making
the bottom thereof flexible and capable of being moved or by using a screwed plug to
constitute the bottom of tube, which plug can be screwed up or down to get the
required adjustment. In Figure 25 I have shewn for this purpose, a flexible bottom
to the tube at 6 and a screw 7 for adjusting it to regulate the height of the liquid. 2
are levers or arms fixed onto the ends of the plugs of the taps, and at an angle with
the axes of the taps. When the taps are closed the arm r makes contact between the
springs and the wire y² joined to one pole of the battery by reason of the said arm r
pressing (as it is turned) against the inclined surface of the piece s and the arm 72
makes contact with the wire y' going to the other pole of the generator thus completing
the electric circuit after the taps are closed the contacts should be so arranged that
continuity of the circuit is not made until after the taps are closed and so that the
contacts can be separated afterwards without opening the taps. Or the completion of
the circuit may be effected by the action of a separate switch. The current passes
from the spring s through the wire by the metal connections or carriers = 22 23
through the metal tube 12 and by the metal of the tap v through the metal arm 7².
Having now particularly described and ascertained the nature of my said Invention
and in what manner the same is to be performed I declare that what I claim is
First An Electric lamp for the purposes herein before described the said lamp
consisting of the parts arranged combined and constructed substantially as herein-
before described with reference to Figures 1 to 15 of the accompanying Drawings
whether secondary cells or primary cells be used as the generator of Electricity
substantially as hereinbefore described.
Second In electric lamps for the purposes hereinbefore described the combination
of a body part forming or containing the cells and a lid with intervening elastic plugs
discs or closures which are pressed down when the lid is secured so as to close the
cells and prevent escape of Electrolyte substantially as hereinbefore described and
illustrated in the accompanying Drawings.
Third In Electric lamps for the purposes hereinbefore described carrying the
terminals of the battery down through channels in the battery block or body of the
lamp to the bottom or near the bottom thereof substantially as and for the purpose
hereinbefore described.
Fourth An electric lamp and indicator for use in mines or places where the
atmosphere is to be tested for explosive or ignitable gases the said lamp and indicator
being combined in one article substantially as hereinbefore described.
Fifth The several arrangements and combinations of parts constituting the electric
safety or miners lamps severally illustrated by Figures 1 to 5 by Figure 6, by
Figures 7, 8 and 9 and by Figures 12 and 13 and by Figure 15 of the accompanying
drawings whether an explosive gas indicator be combined therewith or not
Sixth-An electric indicator for ascertaining the presence of explosive or ignitable
gases in mines or other places the said indicator having a chamber into which the
atmosphere to be tested passes in combination with an electric generator and circuit
and a resistance or ignition wire enclosed in the said chamber the said chamber being
closable so as to isolate its contents from the external atmosphere whilst the testing
current is on substantially as hereinbefore described and whether combined with a
lamp or not.
Seventh-An electric indicator for ascertaining the presence of explosive or
ignitable gases in mines or other places the said indicator having a chamter into
which the atmosphere to be tested passes in combination with an electric generator
and circuit and a resistance or ignition wire enclosed in the chamber and with a
B

page_text: switch or means whereby the chamber is first closed and afterwards the electric circuit
is completed substantially as hereinbefore described and whether combined with a
lamp or not.
Eighth An electric indicator for ascertaining the presence of explosive or ignitable
gases in nines or other places the said indicator having a chamber into which the
atmosphere to be tested passes in combination with an electric generator and circuit
and a resistance or ignition wire inclosed in the chamber and heated by the current
and with a switch or means whereby the chamber is first closed and afterwards the
electric circuit is completed and whereby on the backward movement of the switch or
the like the electric circuit is broken whilst the chamber still remains closed substan-
tially as herein before described and whether combined with a lamp or not.
Ninth An electric indicator for ascertaining the presence of explosive or ignitable
gases in mines or other places the said indicator being arranged or constructed as
claimed by either of the last preceding three claiming clauses and having combined
therewith on the same electric circuit a resistance situated in a normal atmosphere
substantially as and for the purpose of comparison with the resistance in the atmo-
sphere to be tested substantially as herein before described and whether combined with
a lamp or not.
Tenth An electric indicator for ascertaining the presence of explosive or ignitable
gases in mines or other places the said indicator being arranged or constructed as
claimed by either the sixth seventh and eighth claiming clauses and having combined
therewith a gauge substantially as and for the purpose hereinbefore described whether
combined with a lamp or not.
Eleventh-The several arrangements and combinations of parts hereinbefore
described constituting the several electrical indicators for testing atmospheres for
explosive or ignitable gases and as illustrated respectively in Figures 17 to 20 in
Figure 24 and in Figures 25 and 26 of the accompanying drawings.
J. HENRY JOHNSON,
Agent.