IMPROVEMENTS IN STREET AND OTHER LAMPS AND LANTERNS
Year: 1865

page_text: LETTERS PATENT to John William Gregg, of. 18, Upper Sackville
Street, in the City of Dublin, Lamp Manufacturer and Gasfitter, for
the Invention of "IMPROVEMENTS IN STREET AND OTHER LAMPS AND
LANTERNS,"
Sealed the 14th July 1865, and dated the 18th January 1865.
PROVISIONAL SPECIFICATION left by the said John William Gregg,
at the Office of the Commissioners of Patents, with his Petition, on
the 18th January 1865.
I, JOHN WILLIAM GREGG, of 18, Upper Sackville Street, in the City of
Dublin, Lamp Manufacturer and Gasfitter, do hereby declare the nature of
the said Invention for " IMPROVEMENTS IN STREET AND OTHER LAMPS. AND
LANTERNS," to be as follows:-
This Invention relates to improvements in lamps or lanterns intended
either for in-door or out-door use, the object to be attained being increased.
illuminating power, whether using gas, oil, or other inflammable fluid,. without
increasing the cost of burning, and without materially adding to the expense
of construction.
According to this Invention it is proposed to make the glass of the lamp
or lantern, or that part which encloses and surrounds the flame, of a shpae
tapering downwards, and to form the sides thereof of bent glass in lieu of

page_text: flat panes as hitherto adopted in street lamps, whereby less resistance is offered
to the wind. The top or dome of the lamp or lantern consists of an earthen-
ware or china reflector, which is curved or otherwise shaped to suit the angle
of reflection according to the position of the lamp. This reflector may or may
not project or overhang beyond the circumference of the top of the lamp, and
such projecting part may be made of tin or other bright metal on the under
side. When gas is used the tap or regulator may be situate near the centro
of the lamp, and this tap may either be of the ordinary construction, or it may
consist of two concentric tubes, one moving up or down inside the other, and
having a slot formed therein to serve as a guide; the gas is let in through the
inner tube when it is drawn down, and is shut off by pushing up that tube
until it is arrested by a stop. At the bottom of the lamp or lantern there is
fitted a trap door composed of metallic gauze, which admits air freely, and
affords access to the interior of the lamp or lantern when lighting or cleaning
The hot air escapes through suitable apertures at the top. The
addition of the reflector, which can be readily cleaned by simply wiping the
same, greatly augments the lighting power obtained from a given flame by
directing and concentrating the rays of light downward into the street or in
any other direction required, in lieu of allowing a large proportion to be
diffused in directions in which they are not required. The lamp may be
supported in a ring or band suspended to the ceiling supported by a wall
bracket, or attached to a bracket secured to a pillar or other support, and as
there is less metal work underneath the lamp or lantern than in any other at
present in use, shadows will be almost entirely avoided.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John William Gregg in the Great Seal Patent Office on
the 14th July 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
WILLIAM GREGG, of 18, Upper Sackville Street, in the City of Dublin, Lamp
Manufacturer and Gasfitter, send greeting.:
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of January, in the year of our Lord
Oue thousand eight hundred and sixty-five, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John William Gregg, Her special license that I, the said
John William Gregg, my executors, administrators, and assigns, or such

page_text: others as I, the said John William Gregg, my executors, administrators,
or 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 King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of Man,
an Invention for "IMPROVEMENTS IN STREET AND OTHER LAMPS AND LANTERNS,"
upon the condition (amongst others) that I, the said John William Gregg,
my executors or administrators, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the 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 John William Gregg, do hereby
declare the nature of my said Invention, and in what manner the same is to bo
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say:-
My said Invention relates to improvements in lamps or lanterns intended
either for in-door or out-door use, the object to be obtained being increased
illuminating power, whether using gas, oil, or other inflammable fluid, without
increasing the cost of burning, and without materially adding to the expense
of construction.
According to this Invention it is proposed to make the glass of the lamp
or lantern, or that part which encloses and surrounds the flame, of a shape
tapering downwards, and to form the sides thereof of bent glass in lieu of
flat panes as hitherto adopted in street lamps, whereby less resistance is offered
to the wind. The top or dome of the lamp or lantern consists of an earthen-
ware or china reflector, with or without a metallic covering, which is curved
or otherwise shaped to suit the angle of reflection according to the position of
the lamp. This reflector may or may not project or overhang beyond the
circumference of the top of the lamp, and such projecting part may be made of
tin or other bright metal on the under side, or painted white. When gas is
used the tap or regulator may be situate near the centre of the lamp, and this
tap may either be of the ordinary construction, or it may consist of two con-
centric tubes, one moving up or down inside the other, and having a slot
formed therein to serve as a guide; the gas is let in through the inner tube
when it is drawn down, and is shut off by pushing up that tube until it is
arrested by a stop. At the bottom of the lamp or lantern there is fitted a.trap

page_text: door composed of metallic gauze, which admits air freely, and affords access
to the interior of the lamp or lantern when lighting. The hot air escapes
through suitable apertures at the top. The addition of the reflector, which
can be readily cleansed by simply wiping the same, greatly augments the
lighting power obtained from a given flame by directing and concentrating the
rays of light downward into the street or in any other direction required, in lieu
of allowing a large proportion to be diffused in directions in which they are not
required. The trap door, which is weighted to cause it to close of itself, enables
the lamp to be lighted by a small lamp on the end of a pole which is inserted
upwards through the trap door for that purpose, thus dispensing with the use
of a ladder except for the purpose of cleaning the same, the tap or regulator
being opened and closed by the pole used in lighting. The lamp may be sup-
ported in a ring or band suspended from the ceiling, supported by a wall
bracket, or attached to a pillar or other support, and as there is less
metal work underneath the lamp or lantern than in any other at present
in use, shadows will be almost entirely avoided. The whole is put together
or taken asunder by three screws at each end of the ribs or sashes of the
lantern.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the Sheet of Drawings hereunto annexed, the
same letters of reference indicating corresponding parts in all the corresponding
Figures.
Figure 1 of my Drawings is a Diagram showing the principle upon which
my lamp is constructed; Figure 2 is a vertical sectional elevation of my
improved lamp provided with a gas burner, and intended for use as a street
lamp; Figure 3 is a sectional plan of the same taken along the line 1-2
in Figure 2; and Figure 4 is a vertical section of the tap or cock which I
prefer to use in my improved gas lamp.
In the Diagram, Figure 1, A is the flame forming the centre of a circle
(shown in dotted lines), the diameter of such circle varying according to the
size of the lamp to be produced. A, G, and A, F, are rays at angles of 45°
from the vertical impinging the circumference at the points G and F. C, D, A,
is a quadrant subdivided equally by the point F from which the line F, H,
perpendicular to the plane G, F, is drawn, and as A, F, H, is the angle of
incidence, H, F, I, will consequently be the angle of reflection, the reflected
rays being indicated by the lines G, K, and F, I. G is the centre of the
segment C, B, and therefore the segment G, C, F, is equal to one-fourth the
circumference of the circle B, C, D, E. G, F, is the chord of the arc G, C, F,

page_text: and the right lines G, L, and F, M, forming the sides of the lamp, are each
equal to the right line G, F. The top of the lamp is formed by the arc
G, C, F, and the bottom by the right line L, M, consequently L, G, C, F, M,
will appear as the outline or contour of the lamp or lantern.
In Figures 2 and 3, A represents the glass sides of the lamp which are fitted
into light metal frames B, and are tapered and bent in lieu of being flat, so
as to form a circle in horizontal section, and afford less resistance to the wind
than when flat sides are employed. C is a curved earthenware or china
reflector, and may or may not have a metallic covering constructed so as to
suit the angle of reflection desired, and forming the top or dome of the lamp.
This reflector I prefer to make so as to project slightly beyond the sides of
the lamp as shewn. D is the gas burner which is situate near the centre of
the lamp, and E is a sliding tap (shown in enlarged detail at Figure 4) for
turning on and shutting off the supply of gas. This tap consists of an inner
tube F, to which the burner is screwed, sliding gas-tight in the end of the
outer tube G which is fixed. The bottom of the inner tube is closed by a
screwed cap or otherwise, and a number of lateral perforations are made in
the tube near its lower end. A projecting arm I attached to the tube F
enables it to be easily raised or lowered by means of a pole employed in
lighting the lamp, a small lantern being fitted to the end of such pole when
used for that purpose.
When the tube F is pushed up the gas will be shut
off, as the perforations will be closed by being concealed within the contracted
part a of the outer tube, and when the tube F is drawn down to the position
shown in the Drawing the gas will have free passage through it to the burner.
The upward and downward play of the tube F is controlled or checked by the
pin and slot at a. Any suitable packing may be employed at a¹, as shown
in the Drawing, to ensure the tightness of the sliding joint. The bottom of
the lamp is composed of finely perforated metal or wire gauze K (Figure 3),
one half of which is hinged so as to open upwards, as shown in the form of
a trap door c, the door or flap being so weighted as to close by its own
gravity. This openwork bottom, in combination with suitable outlets at the
upper part of the lamp, ensures a constant supply of air to the burner. The
object of the hinged flap c is to admit of the end of the lighting pole being
introduced for the purpose of turning on the gas and lighting the same, or of
turning it off, whereby the necessity for a ladder is obviated. One of the
panes of glass may be made to open for the facility of cleaning the interior of
the lamp.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried

page_text: into effect, I would observe in conclusion that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent is,―
First, the peculiar form and construction of lamp or lantern, and the com-
bination therewith of the reflector C, sliding tap E, wire gauze bottom K, and
flap or door c, substantially as herein-before described and illustrated by my
Drawings.
Second; the peculiar construction of sliding tap or cock, and its application
to gas lamps, as herein-before described.
In witness whereof, I, the said John William Gregg, have to this my
Specification set my hand and seal, the Sixth day of July, in the year
of our Lord One thousand eight hundred and sixty-five.
JOHN W. GREGG. (L.S.)