IMPROVEMENTS IN SIGNAL AND OTHER L.AMDO
Year: 1872

page_text: LETTERS PATENT to Thomas Linwood, of the City of Glasgow, in
the County of Lanark, North Britain, Tin Smith, for the Invention
of "IMPROVEMENTS IN SIGNAL AND OTHER L.AMDO"
Sealed the 17th January 1873, and dated the 24th July 1872.
PROVISIONAL SPECIFICATION left by the said Thomas Linwood at the
Office of the Commissioners of Patents, with his Petition, on the
24th July 1872.
I, THOMAS LINWOOD, of the City of Glasgow, in the County of Lanark,
North Britain, Tin Smith, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN SIGNAL AND OTHER LAMPS," to be as follows,
that is to say :—
This said Invention has reference to and consists firstly in new or
improved shapes and constructions of glasses or lenses made of ordinary
pure crystal or other glass, or of colored glass, for refracting and con-
verging the rays of light of steam ship and other signal lamps, ranged
and secured (in one, two, or more) individually or conjointly to and round
the metal sides or case of the lamp in the horizontal central plane of

page_text: and at the radial angles it is desired to throw the light; and, secondly,
this Invention consists in certain improvements in the construction and
arrangement of the oil supplying vessel and its connections with the
wick Lube of the “moderator” lamp, much used for signal lights, and in
the arrangements of details for the ventilation and adınission of air
thereto, without draughts or currents; by which improvements such
signal lamps are made more convenient and efficient, and when arranged
and fitted with the improved lenses under the first head, show their light
more strongly or brilliantly, and at a greater distance, and definite or
desired angle than has heretofore been the case with such signal lamps
as hitherto constructed and used.
or
66
The nature and novelty of the first part of this Invention substantially
consists in forming the said new or improved lenses with a bull's-eye"
in the centre of each, having a set of nearly parallel two-faced (prismoidal
shaped) annular or elliptical rings formed round it; the two faces
and sharp angle or edge of each ring projecting out at such angles (to
the body and smooth back face, which may be of a flat disc, segmental,
or convex spherical form, next the light and inside the lamp) that the
faces will refract or reflect, and condense all the rays of light falling on
the inside surface in converging or nearly parallel lines, the faces of each
ring meeting each other in a sharp hollow angle at bottom, so that no
light is lost between the rings or faces; and the general configuration
of the inner face and outer curve formed by these rings may be that of
a disc, the vertical segment of a hollow cylinder (or concave and convex
in horizontal section) or of a sphere round on the outside, and plain, or
hollow in the inside of the lamp respectively (as a plana convex or
minescus lens) with the duplex, angular, or prismoidal rings or circles
formed in one with and completely round the bull's-eye and cach other,
until when more than one lens is used the outer rings meet in the
horizontal central plane of the light, and above and below this the rings
are continued so as to meet in corner segments at the vertical centro
line between the lenses, and fill up the whole parallel space between the
upper and lower metallic segmental rim or bizzles for holding and
securing the lenses in proper position in the outer shell or case of the
lamp, and which improvement and arrangement of the lenses enable the
lamp to be of a low and compact shape. These lenses may be formed in
the said manner with their central "bull's-eyes" and prismoidal dioptric
rings, either by being merely compressed in moulds or matrices while

page_text: desired.
In some cases the "bull's-cyc" might be made in the usual manner,
separate from the set of angular faced rings, and afterwards fixed in
their centre, and the whole might be mado in the form of a round or
oval lens (without being made rectangular by the corner segments) and
fixed in a frame or bizzle of the like shape in the lamp. To maintain
the said advantageous low shape of the lamp, and get the sliding bottom,
carrying its oil vessel and wick tube, easily inserted from the door
behind the lenses, the nature and novelty of the second improvements
consist in fixing the ordinary oil cylindrical supplying chamber or fount
on its side horizontally to the sliding bottom, with a short, close, vertical
filling pipe leading up from the extreme end of the short rack tube, in
this case laid horizontally in a line with the axis and at the back end of
the cylinder behind the spring and piston, through and from the front
end of which a small oil conducting tube is led and soldered to the
bottom of the wick tube, which is soldered vertically to the centre of the
sliding bottom, high enough to have the light in the horizontal central
plane of the lenses. The wick tube has an outer tube soldered round it
with an annular oil waste space between them, from the bottom of which
a close tube is soldered, and led up to the top of the filling pipe, so that
after the supplying cylinder is filled and the closing cap screwed down,
and the piston drawn up against the power of the spring by its rack and
pinion to the back end, as usual, the oil is pushed out and supplied from
the front of the cylinder and piston by the spring through the new.
conducting tube to the wick; any extra oil supplied or flowing over the
top of the wick tube runs into the annular space outside, from which it
flows through the return tube into the filling pipe by gravitation, and
the vacuum or suction at the back of the piston, the supply vessel and
its filling pipe being lower than the wick tube, the central tube,
through which air ascends to the flame from the space between the
sliding bottom and the bottom of the lamp is made a little higher than
the outer wick tube so that no oil can escape down it, and otherwise it
is fitted with the wick holder, and rack and pinion for working it as
usual.

page_text: Another improvement consists in forming a rectangular recess round
the outer sides of the close space below the sliding bottom, with a
vertical horizontal division partition having a row of holes in the latter
below a recess for being filled with wool or other porous material all
round the outside of the wall of the close chamber, so that the air first
enters by the rows of holes in the bottom of the lamp and rectangular
space, passes laterally some distance below the horizontal division plate
and then up through the holes and wool above, where it has again to
pass over the vertical division plate to enter the rows of holes in the
sides of the close space below the sliding bottom, having the holes in it
for conducting the air direct up to the flame and across the inner faces
of the lenses, which improvements effectually prevent all irregular
currents of air within the lamp, and regulate its supply steadily up the
tube and rows of holes round it to supply the flame, and also up tho
back of the lenses to keep them free from moisture, and thus thoroughly
ventilate the lamp in an improved manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Linwood in the Great Seal Patent Office
on the 23rd January 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
LINWOOD, of the City of Glasgow, in the County of Lanark, North
Britain, Tin Smith, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of July, in the year
of our Lord One thousand eight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas Linwood, Her special
licence that I, the said Thomas Linwood, my executors, adminis-
trators, and assigns, or such others as I, the said Thomas Linwood,
my executors, administrators, and 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 Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN SIGNAL AND OTHER LAMPS," upon the condition (amongst

page_text: others) that I, the said Thomas Linwood, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and seals, 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 Scal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Thomas Linwood, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement in writing, reference being had to the
accompanying Sheet of Drawings, and to the letters and figures marked
thereon, that is to say :-
My said Invention has reference to, and consists firstly and mainly in
new or improved shapes or constructions of glasses or lenses A made of
ordinary pure crystal or other glass, or of colored glass, for refracting
and converging the rays of light of steamship and other signal lamps,
ranged and secured (in one, two, or more individually or conjointly) to
and round tho metal sides or case of the lamp, in the horizontal
central plane of and at the radial angles it is desired to throw the light;
and, secondly, this my said Invention consists in certain improvements
in the construction and arrangement of the oil supplying vessel and its
connections with the wick tube of the "moderator" lamp, much used
for signal lights, and in the arrangement of details for the ventilation
and admission of air thereto without draughts or currents, by which
improvements such signal lamps are made more convenient and efficient,
and when arranged and fitted with the improved lenses, under the first
head, show their light more strongly or brilliantly and at a greater dis-
tance and a more definite angle than has heretofore been the case with
such signal lamps and lenses, as they have heretofore been constructed
and used; also enabling these improved lamps to be made of a lower
and more compact shape.
And in order that the nature of my said Invention, and the manner
of performing the same may be properly understood, I shall now proceed
to describe the several illustrative Figures on the Sheet of Drawings
which I have hereunto appended for the purpose of showing the best.
modes and means I am at present aware of for putting the Invention.

page_text: into effect or practice, the same reference lettors and numerals indicating
the same or like parts in all the Figures.
-
· Figures 1 and 2 are a front elevation and a vertical section respectively
of a
"mast head" signal lamp for steam and other ships or vessels, con-
structed in accordance with and illustrative of one modification of my
said Invention and improvements, and fitted with three of my improved
lenses A for such lamps; and Figure 3 is a horizontal section of the
same lamp taken on the lines 1---1, 2---2, through the centre of the
light, lenses, and lower part, in Figure 1, while Figure 4 is a vertical
section of the lower part of this lamp to show the improvements for
admitting the air thereto.
Figure 5 is a front elevation; and Figure 6, a horizontal section
taken on the line 1---1, in Figure 5, both of a modification of my
Invention and improvements, as applied to a “starboard” sigual side
lamp for ships, with two of my said improved lenses A fitted in it.
Figures 7, 8, and 9 are respectively a front elevation, a vertical and a
horizontal section of one of the new or improved lenses A, as detached
from the lamps, Figures 1 to 6, shown half full size.
Figures 10 and 11 are a front elevation and a horizontal section of
another modification of the improved lenses A from that shown in
Figures 1 to 9; and Figures 12 and 13 are side or edge elevations of the
same lens A, Figures 10 and 11, the first showing the lens straight or
as a segmental lens, and the second as a curved or as a part of a hollow
sphere, both with the bull's-eye and dioptric rings A', A", on the outer
surface.
Figures 14 and 15 are a front elevation and a plan respectively of a
different modification of the new or improved lens A, in which the
corners or parts a" of the surface beyond the rings A" are filled up with
dioptric bars A™ in the vertical direction instead of in the horizontal
direction, as shown in Figures 7, 8, and 9; and Figures 16 and 17 show
edge views of this construction of lens, Figures 14 and 15, either
straight or curved respectively, as stated in reference to Figures 12
and 13.
Referring to Figures 1 to 9, the nature and novelty of the first part
of my said Invention substantially consists in forming the said new or
improved lenses A with a "bull's-eye" A' in the centre of each, having

page_text: .
---
a set of nearly parallel two-faced (prismoidal or V shaped) annular or
elliptical rings A", A², formed round it; the two faces and sharp angle
of each ring projecting, by preference, outwards as sections or edges
of larger "bull's-eyes" at such angles (to the body and smooth back
face a, a, which in these Figures is segmental, but may be of a flat
or disc shape, or of convex spherical form next the light and inside
of the lamp, as shown in Figures 13 and 17) that the face A¹³, A",
(of the bull's-eye and rings) will refract (or reflect) and condense all
the rays of light, as z, falling on the said inside surface a, a, in more
converging or parallel lines outside the lamp ¹, ¹, Figures 2, 3, and 6,
than usual in such lamps and lenses; the faces A", A², of the adjacent
rings meet each other in a sharp hollow angle at the bottom a¹, so that
no light is lost between the main refracting faces A¹, A", A", of the
"bull's-eye "A" and rings A", A². The general configuration of the inner
face a and outer curve formed by these rings, may be that of a polygonal
or round disc (as indicated by the dotted lines 3 - 3 in Figures 9
and 11) the vertical segment of a hollow cylinder (or concave and
convex in horizontal section, and straight in vertical section, Figures 1
to 12, and 14, 15, 16) or of a hollow sphere round on the outside and
hollow or plain in the inside of the lamp respectively, as indicated at
3-3, Figures 11, and 13, 17, (as a plana convex or minescus lens)
with the duplex angular or dioptric prismoidal rings or circles A"
formed in one with and completely round the " bull's-eye" A' and
each other until they nearly reach the outer edges a', a", of the fixed
width or height of the body A of each whole lens; or when more than
one lens A is used the outer rings may meet cach other in the horizontal
central plane 1 1 of the light, and above and below that plane' the
rings A" are continued in bars or segments A" either parallel to that
plane, Figures 7, 8, and 9, or concentrically, Figures 10 to 13, to meet at
the corners a" and vertical central lines aª a² between the lenses
A, A, so as to fill up the whole parallel space between the upper and
lower parallel edges a, a', held by the metallic segmental rim or bizzles
b, b, for holding and securing the lenses A, A, in proper position in
the outer shell or case B of the lamp. These lenses A may be formed
in the said new or improved manner with their central "bull's-eyes" A'
and prismoidal dioptric rings A", A", either by being merely com-
pressed into properly shaped and polished moulds or matrices, while
the glass or crystal is in a molten state, or they may be approximately
compressed to the shapes and afterwards cut, ground, and polished to
.

page_text: the proper shape described and shown in the accompanying Drawings,
so as to produce the refraction and condensation of the rays indicated
by the lines, ≈, and 2³, 2¹, Figures 2, 3, and 6, from the lamp Z
through the "bull's-eye" A' and curved or angular faces A", A", of
the rings to the extent and angles desired to make the light to be scen
at the desired greater distance and particular angle indicated by the
central angled lines Z, Z, of each lens A.
In some cases the "bull's-eye" A' might be made in a usual manner
separately from the set of angular faced rings A", and afterwards fixed
in a hole or recess formed for it in the centre of the rings A", A", and
the whole (bull's-eye and rings) might be made in the form of a round
or oval lens (without being made rectangular with the corner segment
at a"), and fixed in a frame or bizzle (as b, b',) of the like shape in the
lamp case B to fit it.
Referring to Figures 1 to 6 it will be seen that the general con- 1
figuration of the case B of these improved lamps is much as usual, as
also the construction of oil vessel c, c', at wick tube c", screw ¿ª for
raising the wick, with the reflector mounted as usual behind the
light Z, all being fixed in the centre of the sliding bottom d, inserted
through the door B' of the case at the back into grooves d' over a close
air supplying space D below it and above the actual bottom B" of the
main case B. The central tube e, through which air ascends to the
flame Z from the space D. between the sliding bottom d and the
bottom B" of the lamp B is made a little higher than the level of the
oil and wick chamber c, c', so that no oil can escape down it; and 2
otherwise the lamp proper c, c', is fitted with the wick holder e" by
the ordinary top perforated disc and fixing screw at top c³, where the
air passes up close to the flame Z through the tube e from the closo
chamber D, and also up through the outer circle of holes e' round the
bottom of the wick chamber c', so as to thoroughly supply the air from 3
the outside without injurious draught to the light when it reached the
chamber D by the following improved means, forming another and
special feature of my said Invention for improved signal lamps, and
which consists in forming the rectangular recess E, E', round and along
the outsides of the two sides D' of the close space D below the sliding
bottom d with a horizontal division partition E", having a row of
holes in the latter below a recess E' for being filled with wool or
other porous material as the diagonal layer of wire gauze E³ on the

page_text: outside of the wall D' of the close chamber D, and preferably between
the two vertical divisions G, G', all so that the air, which first enters by
the rows of holes F in the bottom B" of the lamp and rectangular
space E, passes laterally some distance below the horizontal division
plate E, and then up through the holes F on the outside of the
division G, then through the row of holes FS in it, and up through the
wire gauze E³, or it might be wool filling the space E¹ above, where it
has again to pass over the vertical division plate G' to enter and pass
through the row of holes D³ in the sides D' of the close space D below
the sliding bottom d, having the tube and holes e, e¹, in it for con-
ducting the air direct up to the flame Z, and those I round and below
the inner faces a, a, of the lenses A, so as to pass up across them, which
improvements effectually prevent all irregular currents of air within the
lamp and regulate its supply steadily up the tube e and row of holes e²
round it to supply the flame, and also up through those H, across the
back of the lenses A to keep them free from condensed vapour or
moisture, and thus thoroughly ventilate the lamp in an improved
manner, all as indicated by the arrows in Figures 2, 3, and 4. The
products of combustion pass direct up through the bell-mouthed conical
conductor to the interior of the small hollow dome cap ¹, hinged at
back to the carrying neck or hood h, to which the strong hoisting
shackle h¹ is jointed, so that when the lid or cap f¹ is fixed down by the
front hand screw f" the products of combustion pass out through the
ring of small holes f, and up the small annular space /* between the
cap fand the top of the hood h, assisted by any current or wind that
may be blowing outside against the domed top B³ and hood h, which
passes up the narrow space " between them, as indicated by the bluo
arrows at that part, while the domed top of the cap f' deflects the wind
off the top, and any little that may catch one side of the hood h and
pass down the annular space h² passes out at the lower space ", not
being able to enter the lamp by the deflecting cone g, supporting the
central conductor f, although the current of air for drying the lenses and
ventilating the sides and top of the lamp passes out through the angular
covered holes g', which nevertheless will not allow the outer air to enter,
as both the sides of the cone g and the covers on the holes g' deflect the
current up or down the annular space h² as they pass. The eyes B' are
secured to the sides of the case B at the top and bottom of the lamp to
guide and hold it by the wire ropes and bars for taking up and down
and securing the case B by these eyes at the mast head. In this lamp,

page_text: Figures 1 to 4, there are three of the new or improved lenses A. fitted in
the front and round the two sides of the main case B of the lamp, fitting
each other and filling the space made for them very closely, so that no
air current or rain can get into the lamp or light except through the
holes in the bottom B" outside the partition D'; and if by rough
weather or carelessness the oil is spilt over the wick receiver or tube c¹, e,
it only falls down into the bottom of the close recess D, where it is saved
and cannot reach up to the holes D³, where the air enters, to clog the
wire gauze or wool in the chamber E', which is thereby protected from
the evil effects of oil inside, and the rain and rough weather outside.
The three lenses A. are fixed by the outer rim b' of the holding frame b, b',
so that it can easily be unsoldered and any lens taken out and renewed
in a few minutes; and from Figure 3 it will be seen that they are set
with the axis Z, Z, of the rays and light passing through them, the one
directly forward and the other two Z, Z', some degrees more than right
angles on the opposite sides thereto.
Referring to Figures 5 and 6 the general construction of the improved
parts of the lamp B and lenses A. are substantially the same as shown
and described in reference to the more completo and minute sections of
Figures 1, 2, 3, and 4, except that for this side lamp there are only two
lenses, the one set with its axis Z, Z, nearly directly forward, while the
other Z, Z', is set round to the starboard side, nearly at right angles to
the former; and for this light they have a thin segmental pane of green
or bluish glass a* fitted close to the inner surface a, a, of the improved
lenses A; and for the port light this thin pane would be made of red
glass to show a red light, but otherwise the port signal lamps would bo
constructed similarly to that shown and described in reference to theso
Figures 5 and 6, the axis of the side lens however going out on the port
side, both being fitted with the socket and screw J, J', for securing them
to their holding vertical bar at the side of the ship.
Although the colored glass has been described as placed inside the
lenses A, it will be understood that other transparent colored material
might be employed, as liquids enclosed in a space a on the inside of the
lenses, and when made hollow with a flat plate or thickness of glass, as
indicated by the dotted lines 3, 3, in Figure 11; or the lenses A might
bo.made of colored glass themselves.
And although the bull's-eyes and rings have all been described and
shown as formed on the outer surface, considering this the best con-

page_text: struction, it is to be understood that these could be formed on the inner
surface when desired, with an approximately good effect or result.
Referring to Figure 64, which is a side and edge elevation of an
improved construction of wick holder C, C¹, secured on the arm c³, raised
and lowered by the screw c³, the improvement consists in forming the
front side C¹ of the holder to swivel on a hinge at the lower side C¹¹, so
as to open at top to catch the wick C', where the upper edges of both
sides C, C, of the holder are formed with sharp teeth C to catch the
wick C by the power of a tail C³, as seen in Figures 2 and 6ª, cither
acting on a blade or spiral spring C" carried by the arm c'; or the tail
piece C may be formed as a spring itself, acting on the arm c'. Thus
when the holder C, C³, is raised by its screw c³ to the top of the wick
tube c¹¹, the front C' is drawn open with a wire or sharp instrument and
the lower end of a new wick inserted between the sharp teeth C³; when
the piece C¹ can be released and the wick caught as by a pair of pliers
and drawn down by the action of the screw spindle c³, and raised and
lowered as may be required in trimming the light, all otherwise much in
a usual manner.
"
Another improvement of my said Invention (described as a "second
improvement" in my Provisional Specification) consists in mounting on
the sliding bottom d an improved arrangement of the oil supplying
vessel of the "moderator” construction of lamps and wick tube, instead
of that of the more common lamp described and shown by letters
c, c¹, c¹¹, c³, c¹¹¹, c³, c', in reference to Figures 1 to 6; and although I
have not considered it necessary to show a Drawing of this improvement,
it consists all as follows, namely, I fix the ordinary oil cylindrical sup-
plying chamber or fount of the "moderator lamp on its side
horizontally to the bottom d, with a short close vertical filling pipe
leading up from the extreme end of the ordinary short rack tube (in
this case laid horizontally in a line with the axis of the main cylinder)
and at the back end of the cylinder, behind its spring and piston; and
through and from the front end thereof a small oil conducting tube is
led and soldered to the bottom of the wick tube, soldered vertically to
the centre of the sliding bottom d and high enough to have the light in
the horizontal central flame of the lenses, as described in reforonco to
the light Z. This wick tube has an outer tube soldered round it, leaving
an annular oil waste space between them, from the bottom of which
space a close tube is soldered and led up to the top of the filling pipe, so

page_text: that after the horizontal supplying cylinder is filled and the closing cap
screwed down, and the piston drawn up against the power of its spring
by its rack and pinion to the back end as usual, the oil is pushed out
and supplied from the front of the cylinder and piston (by the action of
the spring) through the new conducting tube to the wick, while any
extra oil supplied or flowing over the top of the wick tube runs into the
new aunular space outside, from which it flows through the new return
tube into the filling pipe both by gravitation and the vacuum or suction
at the back of the piston, the filling pipo and supply vessel or cylinder
being thus lower than the wick tube by placing it horizontally, as
described.
Having thus described and particularly ascertained the nature of my
said Invention, and the manner of performing the same, I may state that
I do not desire to claim the use of horizontal or vertical, straight or
segmental dioptric bars or bands across the surface of the glasses or
leuses for signal lamps, as indicated herein by the letter A (that is by
themselves, or separate from my improved arrangement of bull's-eye and
dioptric rings A") as I consider these may have heretofore been used in
sonic forms, but what I believe to be novel and original, and therefore
claim as the Invention secured to me by the hercin-before in part recited
Letters Patent is,―
First. The construction and arrangement of the parts of signal lamps
and their lenses for ships and other purposes, all substantially in the
new or improved manner and for the purposes herein described and
shown in the accompanying Drawings.
Second. The construction of glasses or lenses for ship and other signal
lamps with a "bull's-eye" and dioptric rings round it, either with or
without the corner parts or surfaces not so occupied by these filled up
with correspondingly shaped segments or bars, cither concentric to the
rings or parallel to the edges of the lens when made polygonal, all
substantially in the now or improved manner and for the
described, and shown in the accompanying Drawings.
purposes herein
Third. The construction of ship and other signal lamps with chambers
and porous material round or along the bottom for the admission of
the air, all substantially in the new or improved manner and for
the purposes herein described, and shown in the accompanying
Drawings.

page_text: Fourth. The arranging of the fountain or oil supplying cylinder
of the "moderator" lamp horizontally to ship and other signal lamps,
all substantially in the new or improved manner herein described.
In witness whereof, I, the said Thomas Linwood, have hereunto
set my hand and scal, this Twenty-second day of January, in
the year of our Lord One thousand eight hundred and seventy-
three.
Witness,
W. R. M. THOMSON,
. Patent Agent,
Glasgow.
THOMAS LINWOOD. (L.S.)