IMPROVEMENTS IN SIGNAL, LANTERNS
Year: 1869

page_text: LETTERS PATENT to William Henry Clapp, of No. 243, Ball's Pond,
in the Parish of Islington, for the Invention of "IMPROVEMENTS IN
SIGNAL, LANTERNS."
Sealed the 17th August 1869, and dated the 11th March 1869.
PROVISIONAL SPECIFICATION left by the said William Henry Clapp
at the Office of the Commissioners of Patents, with his Petition,
on the 11th March 1869.
I, WILLIAM HENRY CLAPP, of No. 243, Ball's Pond, in the Parish
of Islington, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SIGNAL LANTERNS," to be as follows:-
This Invention has for its object to construct a lantern which may
either be used as an ordinary dark lantern or be used as a signal lantern
for showing different colored lights. For this purpose I surround the
lamp of the lantern with a revolving cylindrical slide, such as is used in
an ordinary dark lantern, there being an opening made through the
cylinder, which when brought between the lamp and the lens or glass
Price 8d.1

page_text: of the lantern allows a stream of light to pass from the lantern, but
when the cylindrical slide is turned into the opposite position the light
is shut off from the lens. In some cases the lantern may be made with
more than one lens or glass. In addition to this revolving slide, which
I call the dark or negative slide, I form the lantern with another
revolving cylindrical slide, which is glazed with different colored glasses
or other transparent substance, so that by turning this slide either of
the colored glasses carried by it can be brought between the lamp and
lens, and the lantern thus caused to show a light of any desired color.
One of these slides may be acted on from the top and the other slide
from the bottom of the lantern, or both may be acted on from the top,
or both from the bottom.
Lanterns thus constructed will be very suitable for being used by the
police, as they can use them both as an ordinary dark lantern and also
to quietly give signals to one another at night time. Such lanterns will
also be very useful for the guards of railway trains, and for many other
uses. When the lamp is required to be stationary, and the signal
apparatus large, an indicator with names of colors, and numbered to
show the particular signal required to be given, may be combined with
it, so that the person using the apparatus may have before him an exact
indication of the signals given. The revolving dark or negative slide
may have one or more openings to allow the rays of light to pass
through according to the size of the lamp. Both the negative and the
colored slides may be rotated by means of cog wheels. Ordinary reflecting
glasses or metal reflectors placed at various angles may be used for the
purpose of reflecting the signal light. The whole apparatus may be
turned with or without the reflecting glasses to any required point of
the compass.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Henry Clapp in the Great Seal Patent 3
Office on the 11th September 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HENRY CLAPP, of No. 243, Ball's Pond, in the Parish of Islington, send
greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of March, in the year
of our Lord One thousand eight hundred and sixty-nine, in the
thirty-second year of Her reigu, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said William Henry Clapp, Her
special licence that I, the said William Heury Clapp, my executors,
administrators, and assigns, or such others as I, the said William Henry
Clapp, 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 "Ix-
PROVEMENTS IN SIGNAL LANTERNS," upon the condition (amongst others)
that I, the said William Heury Clapp, 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 Seal Patent Office within
six calendar months next and immediately after the date of the said
Letter Patent,
NOW KNOW YE, that I, the said William Henry Clapp, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say :-
This Invention has for its object to construct a lantern which may
either be used as an ordinary dark lantern or be used as a signal lantern
for showing different colored lights. For this purpose I surround
the lamp of the lantern with a revolving cylindrical slide, such as is
used in an ordinary dark lantern, there being an opening made through
the cylinder, which when brought between the lamp, and the lens or
glass of the lantern allows a stream of light to pass from the lautern,
but when the cylindrical slide is turned into the opposite position
the light is shut off from the lens. In some cases the lantern may
be made with more than one lens or glass. In addition to this revolving
slide, which I call the dark or negative slide, I form the lantern with
another revolving cylindrical slide, which is glazed with different colored
glasses or other transparent substance, so that by turning this slide
either of the colored glasses carried by it can be brought between the

page_text: lamp and lens, and the lantern thus caused to shew a light of any desired
color. One of these slides may be acted on from the top and the other
slide from the bottom of the lantern, or both may be acted on from the
top or both from the bottom.
Lanterns thus constructed will be very suitable for being used by
the police, as they can use them both as an ordinary dark lantern and
also to quietly give signals to one another at night time. Such lanterns
will also be very useful for the guards of railway trains, and for many
other uses.
When the lamp is required to be stationary, and the signal
apparatus large, an indicator with names of colors, and numbered to
show the particular signal required to be given, may be combined with
it, so that the person using the apparatus may have before him an
exact indication of the signals given. The revolving dark or negative
slide may have one or more openings to allow the rays of light to pass
through according to the size of the lamp. Both the negative and the
colored slides may be rotated by means of cog wheels. Ordinary
reflecting glasses or metal reflectors placed at various angles may be
used for the purpose of reflecting the signal light. The whole apparatus
may be turned with or without the reflecting glasses to any required
point of the compass.
And in order that my said Invention may be most fully understood
I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section, and Figure 2 a horizontal section of
a hand sigual lantern constructed according to my Invention.
It consists of a cylindrical body a to which are attached the handles a
and a hook or clip a², by which the lamp may be secured to the waist
belt of the user. The body a has an opening at one side capable of
being closed by a door b carrying the bull's-eye or lens 6 this door
is hinged to the body a as in an ordinary policeman's lantern; c is a
cylindrical screen contained concentrically within the body of the
lantern, it is glazed at c¹ with red glass, and at c² with green glass, and
by turning the cylindrical screen either the red or the green glass can
be brought between the flame of the lamp and the bull's-eye, or if
a white light is to be shewn the part of the screen c which is open or
contains no glass may be brought between the flame and the bull's-eye.
The screen c is fixed upon the bottom or foot d of the lantern which

page_text: is secured to the body, but in such manner that it can be turned freely
upon it by means of a flange upon the lower edge of the body at a*
entering a corresponding groove or channel formed around the upper
edge of the bottom or foot d; e is a spring catch on the body a which
drops into one or other of three holes formed in the body and acts as
a stop to stop the screen when it is so placed that the lantern will
show truly either the red, green, or white light; e* is the dark or
negative. screen, it is of a cylindrical form and enters concentrically
within the screen c, on one side it is open for the passage of the light
and on the other it carries the reflector e¹. The lamp f fits into the
lower end of the screen ex, and is there locked in any convenient manner
The lamp has a stem f¹ fixed on the bottom it passes out through a
hole in the foot d of the lamp, and by it the negative screen e* can be
turned round so as either to shade the light or allow it to shine through
the bull's-eye. At e there is a projection on the negative screen to
drop into corresponding notches in the interior of the body when the
screen has been brought to one or other of the two positions it may
be required to take; g is the lantern top, it is held in its place by spring
catches. The user of the lamp can, as will readily be understood, give
signals according to a prearranged code, by altering the color of the
light shown, and causing it to flash by means of the negative screen.
The number of flashes, their length, the length of the pauses between
them and the color of the light are all capable of being varied in
arranging a code of signals.
Figure 3 is a vertical section of a signal lantern suitable to be shown
at a ship's masthead, and to be operated from the deck, it is furnished
as in the former case with two concentric cylindrical screens capable
of being rotated independently the one of the other. a, a, is the body
of the lantern fitted with a door with a lens or bull's eye in it as in
the lantern shown at Figures 1 and 2, or it may have a glass zone
adapted to show a light around a semicircle of the horizon, or over
such other angle as may be required. a¹, a¹, are halliard rings fixed
to the body for hoisting the lantern and holding it in position; bis
the glazed cylindrical screen within the body, it is provided with glasses
of the colors it is desired to use and is left open on one side to allow
the light to pass freely from the flame to the lens when it is desired
to show a white light. The frame b is fixed at the bottom to the
ring 6 which rests upon the lower end of the body a, and is held

page_text: at Figure 4, and
one of the teeth.
up to it by the foot or bottom c fixed to the body by means of arms
formed in connection with the halliard rings a¹, as is shown; d is
the negative or dark cylindrical screen placed concentrically with
the screen b, it is fixed to a ring d¹ aud is supported at the top of the
body in the same way as is the screen 6 at the bottom. On one side
the cylindrical screen d is open, on the other it is closed and carries
the reflector for the lamp, which itself is fitted in any convenient way
to the lower part of the screen, but so that it can readily be removed
for trimming. The lamp should have an argand or other burner
where a powerful light is required. e is a toothed wheel mounted on
a stud fixed to the body a; and e¹ is a chain wheel fixed to the wheel e,
an endless chain is passed around it and descends to the hand of
the signal man who by means of it can turn the wheel e in either
direction. The teeth of the wheel e as the wheel revolves act upon
teeth on the ring and d¹. A plan of the ring b¹ is shown separately
Figure 5 is a section of a portion thereof taken along
The teeth on the ring 61 are marked 6* and those
on the ring d¹ are marked d*. Each tooth is inserted into a slot in
the ring and is acted on by a spring which at its other end is attached
to the ring. The springs cause the teeth to project through the slots
but by the yielding of the springs the teeth can retire beneath the
surface of each ring. The teeth are each formed with one side upright
or at right angles, or thereabouts, to the plane of the ring and the other
side inclined at a considerable angle. When the wheel eis rotated in a
direction to bring its teeth against the upright sides of the teeth b* the
ring 6 will be rotated and with it the screen 6, and so the color of the
light shown will be changed. Whilst the wheel e is revolving in this
direction its teeth will come against the inclined side of one of the
teeth d*, and this tooth will yield by the flexture of its spring and
descend to allow the teeth of the wheel e to pass, and no motion will
be given to the ring d¹ and the screen d. Similarly when the wheel e is
turned, in the contrary direction the screen 6 will remain stationary, and
the color of the light shown will not be altered, but the negative screen d
will be rotated and the light will be caused to flash or will be alternately
shown and obscured. The signal man can thus by moving the endless
hand chain one way and the other through suitable measured distances
vary the color of the light from time to time and produce any required
number of flashes between each change of color, the duration of the
flashes and of the pauses between them he may also vary as he may

page_text: desire, and all according to a prearranged code of signals. If desired
a reflector may be provided so arranged as to reflect a portion of the
light passing through the lens of the lantern down to the signal man
so that the signals may be visible to him. Or a suitable indicator
may be provided in sight of the signal man; it may be worked by the
same hand chain as the signal lantern and consequently in unison with
it. The mechanism for rotating the screens 6 and d may be varied.
My Invention of providing a lantern adapted for signalling with
two concentric cylindrical screens, one glazed and the other a negative
screen to obscure the light from time to time may also be applied in
stationary signal stations on forts or in other places, and sometimes it
may be desirable to show the light only over a small angle. Screens
external of the lautern may in this case be provided so mounted together
with the lantern that the light may be shown in any desired direction.
Figure 6 is a front view, and Figure 7 a side view of an arrangement
suitable for a stationary signal station on land; Figure 8 shows in eleva-
tion, partly in section, a building or station in which the signal apparatus
may be contained, it consists of a room or chamber with a tower rising
from it, at the top of which the light is exhibited. a is the fixed base
of the instrument supporting a turntable upon which the working parts
are supported, on the base circle around the turntable the points of the
compass are marked, and on the turntable an indicator or pointer is
fixed, which when brought to any point marked on the base indicates
that the light is being shewn in the corresponding bearing. The turn-
table has handles upon it by which it is turned round. Ascending
from the turntable to the top of the light tower is a central tubular
upright b, which may be made in lengths bolted or fixed together, and
the lamp is supported on the top of this upright, it has a negative and
a glazed cylindrical screen as already described. These screens in place
of being worked by spring cogs are here represented with spur teeth
upon them at c, c; d is a vertical axis carried in bearings on the upright
b, and e is a tube sliding on this axis with a feather, so that the tube
rotates with the axis; e¹, e³, are pinions on the tube, they work with the
teeth c and d and either the one or the other can be brought into gear
by sliding the tube on the axis by means of the lever f, and the rod g
descending from it to the hand of the signalman who operates it by
means of a suitable handle; h is a hand wheel having on its axis a large
bevilled wheel gearing with the smaller wheel on the axis d, which is

page_text: thus rotated, and it then gives motion either to the negative or to the.
The screens are
glazed screen according to the position of the rod g.
rotated in opposite directions, but each screen always moves in one
direction, this is ensured by mounting two ratchet wheels with teeth
inclined in opposite ways on the axis of the hand wheel h, and pawls
carried by the levers i work on to these wheels. The levers i are jointed
to the rod g, and when this rod is at its highest position the pawl of the
lower lever i acts whilst the other is lifted out of action, and similarly
In order
when the rod g is in its lower position the upper pawl acts.
that the signalman may have represented before him the signals he is
producing the axis of the hand wheel h, is geared by two equal wheels
with a dial axis k, on which two discs. 7 are mounted one behind the
The hinder disc
other and so as to be able to revolve on the axis.
moves with the glazed screen and is prevented from turning in the other
direction by a pawl on its periphery. Portions of its circumference
are painted or may be glazed to correspond with the colors of the screen,
and they come up to the aperture m in the dial plate, and are seen by
the operator as the corresponding glass is brought in front of the lens
of the lantern. The front disc moves with the negative screen and has
When
openings in it corresponding with those in the negative screen.
the negative screen obscures the light the disc covers the main
aperture in the dial plate, allowing however the color on the hinder
disc to be seen through the smaller opening n in the dial plate. The
disc corresponding with the negative screen has projections on it which
act on a striker and sound the bell o each time that a flash is completed.
The rotation of the discs is caused by the dial axis k by means of drivers
acting on ratchets.
For military purposes such signal stations may be so constructed that
they may be moved from place to place on wheels.
Where signals are required to be conveyed for a short distance only
the words, figures, or signs required may be painted on the glazed
cylindrical screen, the light is in this case thrown upon a wall or other
surface at a suitable distance from the lantern, and the signal will then
appear traced in characters in light and shade upon such wall or surface
This method is suitable for use at railway stations to give any simple
direction or information to passengers.
Similar apparatus may be used for giving signals or signs of an
amusing nature, thus a series of figures differing from each other in

page_text: attitude but otherwise similar may be painted on the glazed screen.
The glazed screen in this case should be caused to revolve rapidly, but
step by step, with pauses between each movement, whilst the negative or
dark screen is also caused to revolve rapidly, and so as to obscure the
light during the successive instants of time in which the glazed screen
makes its movements, whilst it allows the light to appear during the
short pauses between the movements of the glazed screen.
The light
passing from the lantern being allowed to fall upon a wall or other
surface the effect of a figure in rapid movement performing a series of
gestures is obtained.
Having thus described the nature of my said Invention, and the
manner of performing the same, I would have it understood that what
I claim is,
The constructing lanterns suitable for giving signals, with two con-
centric cylindrical screens contained within the body of the lantern, and
capable of being rotated therein as herein described.
I also claim the combining indicating mechanism or apparatus
with signal lanterns, substantially as above described.
In witness whereof, I, the said William Henry Clapp, have
hereunto set my hand and seal, this Eleventh day of September,
in the year of our Lord One thousand eight hundred and sixty-
nine.
W. H. CLAPP. (L.S.)