Improvements in and relating to Safety-lamps.
Year: 1889

page_text: Date of Application, 16th Feb., 1889
Complete Specification Left, 24th July, 1889-Accepted, 31st Aug., 1889
PROVISIONAL SPECIFICATION.
Improvements in and relating to Safety-lamps.
I, JAMES THORNE, of 85 Gracechurch Street in the City of London, Merchant do
hereby declare the nature of this invention to be as follows:-
My invention relates to safety lamps and its chief objects are to provide for
increasing the illuminating power of such lamps and to obviate more effectually than
heretofore the liability to explosions of fire damp in coal mines.
One of the most important features of my said invention is the construction of the
lamp in such a manner that it will give a bright steady light which will be com
paratively unaffected either by strong currents of air in which the lamp may be
used or by the ordinary handling of the lamp, or by the inclination thereof; but
which can nevertheless be very readily extinguished if necessary without opening the
lamp.
To accomplish this result, I employ a lamp cone, that is to say, a conical or other
suitably shaped casing which surrounds the wick tube or burner of the lamp. This
lamp cone is provided with suitable orifices round its base for supplying air, and
concentrates the flow and increases the supply of air to the flame and thus promotes
the combustion of the illuminant.
The said lamp cone filling up the space between the wick case and the glass
cylinder provides a combustion chamber of comparatively small capacity thereby
avoiding or obviating the liability to the production of lambent flames around the
wick tube or burner.
•
My improved lamp is, moreover, so constructed that the air requisite for supporting
combustion must first pass upward into the space between an ordinary metal-cap or
bonnet and an ordinary wire gauze cylinder, then through the latter and downward
between two hollow glass concentric cylinders which surround the combustion
chamber or.space and then upward within and through or around the said lamp coue.
It follows that any back draught from the lamp must take the reverse course and
must also pass through the wire gauze. The liability to ignition of the fire damp
in the mine by reason of back draught from the lamp is thus obviated.
In some cases two wire gauze cylinders may be employed.
Another important feature of iny said invention is the provision of improved
devices hereinafter referred to for locking the lamp, which devices are so arranged
that the various parts of the lamp must be properly fitted and secured together before
the lamp can be locked. The danger which frequently arises, with many of the
lamps heretofore constructed, by reason of the lamp being taken down into a mine
with the parts improperly fitted and secured is thus avoided.
Another feature of my said invention is the employment of a reversible; reflector
which can be readily applied to the lamp, without unlocking the same, so as to reflect
the light either upward or downward as may be required.
My said invention, moreover, comprises other improvements hereinafter mentioned.
My said invention is conveniently and advantageously carried into practice as
follows, that is to say :-The frame of the lamp comprises upper and lower rings or
annular pieces firmly connected by means of rods or pillars. The lower ring is
screwed upon the oil reservoir which forms the base of the lamp, in such a manner
that it can be readily unscrewed therefrom, except when the lamp is locked as herein-
after described.
Between the said rings or annular pieces are firmly secured two hollow glass
cylinders one of which is arranged within the other, a suitable annular space being
left between the said cylinders for the passage of air as hereinafter mentioned. The
ends of the said cylinders are ground truly parallel and are securely held in place by

page_text: a perforated ring or annular plate screwed into the aforesaid lower ring of the lamp
frame, washers of asbestos or other suitable material being placed at the ends of the
said glass cylinders to ensure tightness of the joints. When it is desired to withdraw
the glass cylinders for cleaning or other purposes, the said annular plate must be
removed from the lower ring or annular piece of the lamp frame, it is not, however,
necessary to remove or disturb the said annular plate and glass cylinders in order to
trim the lamp, as access to the wick tube or burner can be readily obtained by
unscrewing the lower ring from the oil reservoir and lifting off the lamp cone.
The lamp is provided with a long conical or taper chimney with a small aperture
at the top.
This chimney is made with a perforated flange, whereby it is securely
held between the upper ends of the glass cylinders and the upper ring or annular
piece of the lamp frame. The said chimney can be readily cleaned when the oil
reservoir is detached from the lower ring of the lamp frame without disturbing the
joints at the ends of the glass cylinders.
The perforations in the said flange of the chimney and those in the aforesaid annular
plate at the lower end of the glass cylinders open into the annular space between the
said glass cylinders.
The lamp cone is placed upon the oil reservoir and surrounds the wick tube or
burner; the lower edge of the said cone is preferably fitted into a circular groove
in the top of the oil reservoir. The upper end of the said cone has formed therein a
central elongated hole such as is usually employed in petroleum lamps through which
the flame of the lamp will pass. The said cone is made with a shoulder or flange
against which bears the inner edge of the aforesaid annular plate, when the parts of
the lamp are fitted together, thus firmly holding the said cone in its place. Beneath
the said shoulder or flange, the said cone is perforated as above mentioned to permit
the passage into the same of the air requisite for supporting the combustion of the
illuminant.
Small perforations are, moreover, made in the said cone above the said shoulder or
flange to permit the passage of a small quantity of air from the interior of the cone
into the space above it.
The combustion of the illuminant is greatly increased by the said cone so that a
strong bright light will be produced which by reason of the rapid flow of air between
the flame and the edge of the elongated hole in the said cone, will not be materially
affected by the ordinary rough handling of the lamp. By reason of the more perfect
combustion of the illuminant, there will be less liability to the production of smoke
and soot than in the safety lamps heretofore. constructed.
The wire gauze cylinder or cylinders placed over and around the aforesaid metal
chimney are formed with flanges at their lower ends, whereby they are clamped
between a screw threaded extension of the upper ring or annular piece of the lamp
frame and a flanged ring which is screwed thereon so that it can be readily detached
therefrom except when the lamp is locked as hereinafter described.
By this arrangement the wire gauze cylinder or cylinders can be readily removed
and replaced without disturbing the aforesaid glass cylinders. The said flanged ring
has firmly secured thereto the metal cap or bonnet which encloses the wire gauze
cylinders; and this cap or bonnet is provided on opposite sides with small slots or
windows closed by pieces of mica or other suitable transparent material, so that the
miner can at any time inspect the wire gauze cylinder without removing the said
cap or bonnet.
The upper ring or annular piece of the lamp frame is perforated with a circular
series of holes, and the said flanged ring is formed with elongated apertures. The
air for supporting combustion enters, as above described, through these holes in an
upward direction between the metal cap or bonnet and the outer wire gauze cylinder
or cone; it then passes through the wire gauze and downward through holes in the
flange of the metal chimney an I between the two glass cylinders then through the
perforated annular plate and into and through the aforesaid cone. The air is con-
ducted by the lamp cone directly towards the flame of the lamp; therefore, should
there be sufficient fire damp mixed with the supplied air to form an explosive or

page_text: dangerous mixture, this mixture will either burn and cause an elongation of the
flame of the lap or will explode within the lamp cone with just sufficient force to
extinguish the light and without causing the ignition of the explosive mixture
outside of the said lamp cone, so that no gas will be left burning within the lamp.
The lamp therefore affords clear indications of the presence of fire damp in a
mine.
It will be seen that any back draught from the lamp must pass through the wire
gauze cylinder or cylinders; the lamp, can therefore be used with safety in dangerous
mines. Moreover it can be used in a strong current of explosive mixture without
explosion thereof, and although the light will not be extinguished when the lamp is
subjected to strong currents of air in a mine, it can nevertheless be extinguished
intentionally, if necessary, by suddenly or rapidly raising and lowering it in the air
in a vertical position and thereby causing a concussion of the supplied air.
The metal chimney is preferably made taller than those heretofore employed in
ordinary safety-lamps, in order to increase the draught and consequently the
illuminating power of the lamp and the steadiness of the flame.
By constructing the lamp in the manner above described, I provide for enabling it
to be used with very heavy mineral oils, thus effecting considerable economy whilst
ensuring great safety in the use of the lamp.
Moreover the wick is not consumed to the same extent as in safety lamps hereto-
fore used. Therefore wick composed of wire or asbestos can be employed.
For adjusting the wick, a spindle provided with one or more toothed or roughened
wheels is employed. This spindle extends through the lamp cone.
A hollow spindle
provided with a milled head is passed through a hole in the lower ring of the lamp
frame and engages with the aforesaid spindle so that the wick can be adjusted or the
flame extinguished from the exterior of the lamp, without the necessity for opening
the same.
To provide for securely locking or fastening together the parts of the lamp, so that
the opening of the lamp cannot be effected without the certainty of detection, the
following devices are employed, viz. :-One of the pillars of the lamp-frame is made
hollow or tubular and a bolt is fitted therein and is adapted to enter a hole in the
flanged ring forming the base of the metal cap or bonnet, thus preventing the
unscrewing of the said cap or bonnet from the upper ring of the lamp-frame. The
said boit may with advantage be arranged directly above the hole formed in the lower
ring of the said frame for the reception of the aforesaid hollow spindle of the wick-
adjusting device, so that, when this spindle is in place, the said bolt cannot be with--
drawn from the flanged ring or base of the cap or bonnet. Moreover, by reason of
the engagement of the said hollow spindle with the inner spindle of the wick-
adjusting device, the lower ring of the lamp-frame cannot be unscrewed from the
oil-reservoir until the said hollow spindle is withdrawn.
.It will, therefore, be seen that the parts of the parts of the lamp must be properly
fitted together and the said bolt caused to engage with the said flanged ring before
the hollow spindle can be inserted.
Any suitable device is provided for preventing the withdrawal of the said hollow
spindle except by an authorized person. A convenient device for this purpose.consists.
of a bayonet-joint in which the said hollow spindle is fitted to rotate but is prevented
from endwise movement. The moveable part of this bayonet-joint is provided with an
arın having a bole forined therein; a corresponding hole is formed in the oil reservoir
or base of the lamp in such a position that, when the said bayonet joint is closed, a
lead rivet can be passed through these two holes and secured therein by clinching or
sealing in the ordinary manner, thus preventing the opening of the said bayonet-
joint without destruction of, or injury to the said rivet or seal. Other devices,may,
if desired, be used for fastening the said bayonet-joint in its closed position.
The reversible reflector which, as above mentioned, is sometimes employed, is
preferably inale of conical form. It is moreover so made that it can be slightly
expanded and placed upon the lamp and then contracted so that its inner edge enters
notches formed for the purpose in the pillars uniting the upper and lower rings of

page_text: the lamp-frame; and a screw or other suitable device is provided for securing the said
reflector when contracted.
The lamp is, in some instances, provided with one or more parabolic or other suitable
lenses for more effectually concentrating the light in any desired direction. The said
lenses are preferably secured to the frame of the lamp either permanently or so that
they can be readily removed and replaced.
It is obvious that the construction of the improved lamp can be somewhat modified
without departing from the nature of the said invention.
The oil reservoir is sometimes provided with an extension for permitting the filling
of the same without disconnecting the parts of the lamp, the said extension being
formed with a hole which is closed by a cap or plug.
Dated this 16th day of February 1889.
ABEL & IMRAI,
Agents for the Applicant.
.
COMPLETE SPECIFICATION.
Improvements in and relating to Safety-lamps.
I, JAMES THORNE, of 85 Gracechurch Street, in the City of London, Merchant,
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 relates to Safety-lamps and its chief objects are to provide for
increasing the illuminating power of such lamps and to obviate more effectually than
beretofore the liability to explosions of fire-damp in coal-mines.
One of the most important features of my said invention is the construction of the
lamp in such a manner that I am enabled to employ therein with great advantage a
lamp-cone, that is to say, a conical or other suitably shaped casing which surrounds the
wick-tube or burner of the lamp, and which is formed with an elongated aperture for
the passage of the flame of the lamp, and with suitable orifices around its base for
the supply of air. This lamp-cone concentrates the flow and increases the supply of
air to the flame and thus promotes the combustion of the illuminant, so that very
heavy mineral oils can be used in the lamp, and the lamp will give a bright steady
light which will be comparatively unaffected either by strong currents of air in
which it may be used, or by dust, or by the ordinary handling of the lamp, or by
the inclination thereof, but which can nevertheless be very readily extinguished if
necessary without opening the lamp.
I am aware that attempts have heretofore been made to construct safety-lamps
with ordinary lamp-cones and with other devices for deflecting or concentrating the
air supplied to the flame, so that mineral oils might be advantageously used in such
lamps; but these attempts have failed by reason of defects in the construction of
the lamps.
Now by iny invention I obviate the above mentioned defects and provide a safety
lamp which has been proved by actual trials to be well adapted for burning heavy
mineral oils.
In my improved lamp, provision is made for so directing and controlling the flow
of the air requisite for supporting combustion that it must pass through wire-gauze
then downward between two hollow glass concentric cylinders, then through a
horizontal perforated metal plate arranged beneath the said glass cylinders and then
upward within and through the said lamp-cone. In cases where the lamp has to be
used in nines where the velocity of.the air currents is great, or say over twenty feet
per second, I provide my lamp with an annular piece of wire-gauze above or below
the said perforated plate so that any back current or draught must pass through the
annular piece. The liability to ignition of the fire-damp in a mine by Lack-draught
from the lamp is thus obviated. My lamp thus constructed will be found to fulfil all
the conditions required by the Royal Commissioners appointed to enquire into

page_text: accidents in mines and he a completely safe lamp. In some cases, two wire-gauze
rings may be employed one above and the other below the glass cylinders. I also
provide a taper chimney or flue for the escape of products of combustion. This
chimney or flue extends upward within the metal cap or bonnet nearly to the top
thereof. Therefore the ingress for the supplied air and the egress for products of
combustion, although both in the upper part of the lamp, are nevertheless separate and
distinct from each other.
Another important feature of my said invention is the construction of the lamp so
that the oil-reservoir or base and the upper part thereof comprising the ordinary
metal cap or bonnet and the ordinary wire-gauze cylinder or cylinders can be readily
removed to permit the cleaning of the inner glass cylinder and the metal chimney
or flue, or for other purposes, without disturbing the joints at the top and bottom of
the said glass cylinders.
Moreover by reason of the improved construction of my lamp, it is self-extinguish-
ing in an explosive mixture of fire-damp and air, any inflammable mixture entering
the lamp-cone being ignited by the flame of the lamp and consumed before it reaches
the chimney, and the said flame and that of the inflammable mixture so ignited
being automatically extinguished without the possibility (under any circumstances at
all likely to occur in the working of coal) of igniting the inflammable mixture outside
of the lamp, even when this mixture is passing at a high velocity.
Another feature of my said invention is the provision of improved devices herein-
after described for locking the lamp, which devices are so arranged that the various
parts of the lamp must be properly fitted and secured together before the lamp can
be locked. The danger which frequently arises, with many of the lamps heretofore
employed, by reason of the lamp being taken down into a mine with the parts
improperly fitted and secured, is thus avoided.
My said invention, moreover, comprises other improvements hereinafter described.
In the accompanying drawings, I have shown how my said invention may be con-
veniently and advantageously carried into practice.
Figure 1 is an elevation of one form of iny improved lamp.
Figure 2 is a vertical section on the line x, x, Figure 1, the lamp being shewn
locked.
Figure 3 is a horizontal section on the line r¹, ¹, Figure
,
and
Figure 4 shews a portion of Figure 2, the lamp being shewn unlocked as hereinafter
described.
Figure 5 is a vertical central section, and
Figure 6 a horizontal section on the line ³, x³, Figure 5, illustrating various
modifications of my invention.
Figure 7 is a vertical central section illustrating further modifications thereof.
Like letters of reference indicate corresponding parts throughout the drawings.
a is the oil-reservoir, which forms the base of the lamp. The frame of the lamp
comprises upper and lower rings or annular pieces b, c, firmly connected by means
of rods or pillars d. Or the said rings may be connected by other suitable means.
The lower ring 6 is screwed upon the oil-reservoir a in such a manner that it can
be readily unscrewed therefrom except when the lamp is locked as hereinafter
described. Between the said rings or annular pieces b, c, are firmly secured two
hollow glass cylinders e, f one of which is arranged within the other, a suitable annular
space being left between the said cylinders for the passage of air as hereinafter
described. The ends of the said cylinders are ground truly parallel and the said
cylinders are securely held in place by a perforated ring or annular plate g screwed
into the lower ring b of the lamp-frame, washers of asbestos or other suitable
material being placed at the ends of the said glass cylinders to ensure tightness of
the joints.
The lamp is provided with a long conical or taper chimney or flue h with a
comparatively small aperture at the top. This. chimney or flue is made with a
perforated flange h¹ whereby it is securely held between the upper ends of the glass.
cylinders and the upper ring or annular piece c of the lamp-frame. The perforations

page_text: in the said flange of the chimney and those in the annular plate g at the lower end
of the glass cylinders open into the annular space between the said glass cylinders.
The said chimney should be suitably proportioned to produce the requisite draught
through the lamp without permitting the passage of flame into the wire-gauze
cylinder.
The lamp-conej is placed upon the oil-reservoir and surrounds the wick-tube
or burner a; the lower edge of the said cone is preferably fitted into a circular
groove a² in the top of the oil-reservoir. The said cone is similar to those usually
employed in petroleum-lamps, having formed in its upper end a central elongated
hole through which the Hame of the lamp will pass; but the said cone is made
with a shoulder or flange j2 against which bears the inner edge of the annular plate g,
when the parts of the lamp are fitted together, thus firmly holding the said cone
in its place. Beneath the said shoulder or Hange, the said cone is perforated to
permit the passage into the same of the air requisite for supporting the combustion of
the illuminant. Small perforations j³ are, moreover, made in the said cone above the
said shoulder or flange to permit the passage of air to facilitate the ignition and
promote the combustion of the illuminant.
The combustion of the illuminant is greatly increased by the said lamp-cone so
that a strong bright light will be produced, which, by reason of the rapid flow of air
between the flame and the edge of the elongated hole in the said cone, will not be
materially affected by the ordinary rough handling of the lamp.
Moreover by
reason of the more perfect combustion of the illuminant, there will be less liability
to the production of smoke and soot than in the safety-lamps heretofore used.
When it is desired to withdraw the glass cylinders for cleaning or other purposes,
the said annular plate g must be removed from the lower ring or annular piece b;
it is not, however, necessary to remove the said annular plate or disturb the joints at
the ends of the glass cylinders in order to trim or clean the lamp, as access to the
wick-tube or burner al and also to the interior of the chimney can be readily obtained
by unscrewing the oil-reservoir from the lower ring b.
1
is the wire-gauze cylinder, which is placed over and around the metal chimney
or flue h. This cylinder is formed with a flange at its lower end whereby it is
clamped between a screw-threaded extension c¹ of the upper ring or annular piece c
and a flanged ring 7, which is screwed thereon so that it can be readily detached
therefrom except when the lamp is locked as hereinafter described. By this arrange
ment, the wire-gaaze cylinder can be readily removed and replaced without disturbing
the aforesaid glass cylinders. The said flanged ring bas firmnly secured thereto
the metal cap or bonnet m which encloses the wire-gauze cylinder k.
The upper ring or annular piece c of the lamp-frame is perforated with a circular
series of holes c and the said flanged ring is formed with suitable apertures . The
air for supporting combustion enters through these holes in an upward direction
between the metal cap or bonnet m and the wire-gauze cylinder ; it then passes
through the wire-gauze and downward through the holes in the flange of the metal
chimney or flue h and between the two glass cylinders e, f, then through the perforated
annular plate g and into and through the lamp-cone 7. The air is conducted by the
lamp-cone directly to the flame of the lamp; therefore any inflammable mixture of
fire-damp and air entering the lamp will burn and cause an elongation of the flame
of the lamp, thus indicating the presence of danger; or should there.be sufficient.fire-
damp mixed with the air to forin an explosive mixture, it will explode within the
lamp-cone with just sufficient force to extinguish the flame, so that no gas-will.be
left burning within the lamp and an explosion cannot be caused by the lamp under
any circumstances likely to occur in the working of coal.
For adjusting the wick, a spindle n provided with one or more toothed or roughened
wheels is employed. This spindle extends through one side of the lamp-cone j.
A spindle p provided with a milled head p² and with a socket p is passed through a
hole in the lower ring b of the lamp-frame and engages with the spindle n so that the
wick can be adjusted or the flame extinguished from the exterior of the lamp without
the necessity for opening-the same.

page_text: To provide for securely locking the parts of the lamp, when properly fitted together,
so that the opening of the lamp cannot be effected without the certainty of detection,
the following devices are employed, viz. :-One of the pillars d of the lamp-frame is
made hollow or tubular and a bolt q is fitted therein and is adapted to enter a hole in
the flanged ring forming the base of the metal cap or bonnet m, thus preventing the
unscrewing of the said ring and cap or bonnet from the upper ring c of the lamp
frame. The said bolt is arranged, as shown, directly above and at right angles to the.
hole formed in the lower ring for the reception of the spindle p of the wick-adjusting
device, so that, when this spindle is in place, the said bolt q cannot be withdrawn
from the flanged ring or base of the cap or bonnet m. Moreover by reason of the
engagement of the said spindle p with the spindle n, the lower ring b of the lamp-.
frame cannot be unscrewed from the oil-reservoir a until the said spindle p is with
drawn.
It will therefore be seen that the parts of the lamp must be properly fitted together;
and the bolt q caused to engage with the flanged ring before the hollow spindle p
can be inserted.
I sometimes provide the spindle p with a pin or stop for preventing its complete
withdrawal from the ring b and thus avoiding loss of the said spindle.
ment.
!
Any suitable device is provided for preventing the unlocking of the lamp except
by an authorized person. A convenient device; for this purpose consists of a bayonet-
joint in which the spindle p is fitted to rotate but is restrained from endwise move-
The movable part of this bayonet-joint is provided with an arm r having,
a hole formed therein. A corresponding hole is formed in the part a of the oil-
reservoir or base a of the lamp in such a position that, when the said bayonet-joint
is closed, a lead rivet s can be passed through these two holes and secured therein
by clinching or sealing in the ordinary manner, thus preventing the opening.
of the said bayonet-joint without, destruction of or injury to the said rivet
or seal.
Other devices may, if desired, be used for fastening the said bayonet-joint in the.
closed position.
I find it advantageous, as before mentioned, to provide my lamp with a horizontal
ring or annular piece g³ (Figure 5) of wire-gauze beneath the glass cylinders e, f.
This ring is secured between the said glass cylinders and the perforated ring or
annular plate g, as shown. In some cases, a horizontal ring of wire-gauze may be.
employed above as well as below the said glass cylinders. If desired, the lamp-
cone is connected by a hinge-joint to the oil-reservoir a as shown in
Figure 5.
In some instances, I provide a shield or guard v of wire-gauze in the lower end.
of the metal cap or bonnet m, as shown in Figure 5, to prevent the too rapid ascent,
of the air entering the cap or bonnet m through the holes in the ring 1. Or
in place of the said shield or guard I employ a ring of wire-gauze secured within the
metal cap or bonnet and surrounding the wire-gauze cylinder k, or any other
equivalent device
The metal chimney or flue is preferably made taller than those heretofore employed
in ordinary safety-lamps and of the taper or conical form shown in the drawing, in
order to increase the draught and consequently the illuminating power of the lamp and,
the steadiness of the fame.
I sometimes make the wire-gauze cylinder so that it extends above the lower
edges of the lateral apertures at the top of the bonnet m, as shown in Figure 5 ;
I am thus enabled to use a long chimney without greatly increasing the height of
the lamp.
The spindle n of the wick-adjusting device is preferably provided with a milled
head n² to facilitate the adjustment of the wick when the lamp is open.
The lamp shown in Figure 5 is in other respects constructed in a substantially
similar manner to that described with reference to Figures 1 to 4.
When my improved lamp is constructed as above described with a ring of wire-
gauze beneath the glass cylinders, this ring and the taper chimney or flue are

page_text: sufficient without the wire-gauze cylinder to prevent the passing of the flame so is
to cause an explosion. Therefore should the said wire-gauze cylinder be omitted, the
lamp will still be safe.
In Figure 7 I have shown another modification of my invention, wherein the
vertical bolt is held in its locking position by a shoulder a* on the oil reservoir
or base a, and the lower ring b of the lamp-frame is locked to the said reservoir by
an ordinary locking device comprising arms a, b projecting from the oil-reservoir
and from the said ring b, and provided with corresponding holes to receive a lead
rivet s or the like. A hole or depression is formed in the shoulder a* of the oil-
reservoir in such a position that, by turning the lamp-frame through a certain
angle in unscrewing it from the oil-reservoir, the bolt g will be brought in line with
the said holes or depression and can, therefore, be moved downward to unlock the ring
from the ring c. Or the parts are so constructed that the oil-reservoir must be removed
to permit the unlocking of the ring l.
In the lamp shown in Figure 7, moreover, I employ a modified arrangement of the
wick-adjusting device; the spindle n has fixed thereon a bevel-wheel t which is geared
with another bevel-wheel u fixed upon a vertical spindle u' extending through a tube a
fixed in the oil-reservoir. This spindle has fixed 'upon it below the said oil-reservoir a
milled head or wheel 2 for turning it.
I sometimes provide a lip or flange on the wick-tube to prevent extinction
or diminution of the flame by rapid currents of air passing through the lamp-cone, for
example when the lamp is used in strong up-hill currents. This arrangement or other
suitable means for preventing extinction or diminution of the flame are essential to
the proper working of the lamp when the wire-gauze cylinder is omitted.
It will be seen that any back-draught from my improved lamp must, as above
stated, pass through the wire-gauze, the lamp can, therefore, be used with safety in
dangerous mines. Moreover it can be used in a strong current of explosive mixture
without explosion thereof; and although the light will not be extinguished when the
lamp is subjected to strong currents of air in a mine, it can nevertheless be
extinguished intentionally, if necessary, by suddenly or rapidly raising and lowering it
in the air in a vertical position and thereby causing a concussion of the supplied air.
will be seen, moreover, that, as above stated, the ingress for air and the egress
for the heated products of combustion, though both in the upper part of the lamp, are
separate and distinct from each other.
It
By constructing the lamp in the manner above described, I provide for enabling
it to be used with very heavy mineral oils, of a specific gravity of say '83 and
upward, and having a flashing point of about from 250 to 300 degrees Fahrenheit,
thus effecting considerable economy whilst ensuring great safety in the use of
the lamp.
Moreover the wick is not consumed to the same extent as in safety-lamps hereto-
fore used. Therefore wick composed of wire or asbestos can be employed.
To ensure the most favourable working of the lamp, the cone j, glass-cylinders e, f,
and chimney should be proportioned and arranged in relation to each other substan-
tially as shown in the drawings.
The oil-reservoir is sometimes provided with an extension for permitting the filling
of the same without disconnecting the parts of the lamp, the said extension being
formed with a hole which is closed by a cap or plug.
It is obvious that the construction of the improved lamp can, if desired, be somewhat
modified without departing from the nature of my said invention.
Having now particularly. described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed, I wish it understood that
I claim :-
First. A safety-lamp provided with a lamp-cone such as I have herein before
described and with concentric glass cylinders and so constructed that the base and
upper part of the lamp can be removed without disturbing the joints at the ends of
the said cylinders, substantially as herein before described.

page_text: Second. A safety-lamp provided with a lamp-cone such as I have hereinbefore
described, and so constructed that the air for supporting combustion must pass from
the exterior of the lamp downward through an annular space between two glass
cylinders and then through a horizontal or nearly horizontal perforated plate and ring
of wire-gauze beneath the said glass cylinders and into the said lamp-cone, substantially
as herein before described.
Third. The combination, with the oil-reservoir provided with the lamp-cone, of the
upper and lower rings of the lamp-frame connected by the pillars or their equivalents,
the taper chimney or flue having the perforated flange, the horizontal or nearly hori-
zontal perforated plate (with or without the wire-gauze ring) screwed into the said
lower ring, and the concentric glass cylinders secured between the said flange and the
perforated plate, substantially as, and for the purposes, set forth.
Fourth. The combination, in a miner's safety-lamp, of the lamp-conej, the concentric
glass cylinders e, f, the wire-gauze gl, and the taper chimney or Blue h, substantially as,
and for the purposes, above specified.
Fifth. The combination, in a miner's safety-lamp, of the lamp-conej, the concentric
glass cylinders e, f, and the wire-gauze g', substantially as, and for the purposes, above
specified.
Sixth. The employment, in my improved lamp, of the shield or guard of wire-gauze
or its equivalent over the apertures for the admission of air, substantially as, and for
the purpose, set forth.
Seventh. The combination, with a vertical bolt for locking the cap or bonnet to the
upper ring of the lamp-frame, of a wick-adjusting spindle formed in two parts one,
which serves as a horizontal bolt for locking the oil-reservoir to the lower ring of the
said frame, the said bolts being so arranged that the vertical bolt can be unlocked when
but not until, the horizontal bolt is withdrawn.
Eighth. The improved safety-lamp constructed substantially as described with
reference to Figures 1, 2, 3 and 4, or to Figures 5 and 6, or to Figure 7 of the
accompanying drawings and for the purposes above specified.
Dated this 24th day of Tul 1800
ABEL & IMRAY,
Agents for the Applicant.