IMPROVEMENTS IN SIGNAL APPARATUS FOR GIVING FLASHES OF LIGHT OF DIFFERENT COLORS
Year: 1871

page_text: LETTERS PATENT to Sir William Mitchell, Knight, of 54, Gracechurch
Street, London, and John Joseph Mayo, Esq., of Benhilton, Sutton
Surrey, for the Invention of "IMPROVEMENTS IN SIGNAL APPARATUS
FOR GIVING FLASHES OF LIGHT OF DIFFERENT COLORS."
Sealed the 31st October 1871, and dated the 23rd May 1871.
PROVISIONAL SPECIFICATION left by the said Sir William Mitchell
and John Joseph Mayo at the Office of the Commissioners of
Patents, with their Petition, on the 23rd May 1871.
We, Sir WILLIAM MITCHELL, Knight, of 54, Gracechurch Street,
London, and JOHN JOSEPH MAYO, Esq., of Benhilton, Sutton, Surrey,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN SIGNAL APPARATUS FOR GIVING FLASHES OF LIGHT OF DIFFERENT COLORS," to
be as follows:-
This Invention has for its object to improve the construction of signal
apparatus, adapted for giving flashes of light of different colors, more
especially for signalling with the international code of signals.

page_text: Heretofore it has been proposed to construct lanterns with two internal
screens, each capable of being revolved by handles, either at the sides
or top of the lantern. One of these screens has carried glasses of one
or more colors, so that either one or other colored glass can by turning
the screen be brought behind the lens of the lantern and govern the
color of the light; the other screen has been a "dark screen," which
could be turned into a position to cut off all passage of light to
the lens:
According to our Invention we mount upon the top of a hollow stem
a lantern fitted as above described with two internal screens. The
bottom of the lantern is at its centre attached to the top of the hollow
tubular stem; and in order to be able to revolve the screens two
concentric tubes, or a tube and rod passing up through the stem, are
employed. One tube is attached at its upper end to the bottom of one
of the revolving screens, whilst the other tube or the rod is attached
to the bottom of the other revolving screen; and to the lower end of the
tube and of the rod handles are attached, by which they can be turned
together with the screens carried by them. The bottom of the tubular
stem which carries the lantern is fixed to the centre of a disc, which
at its circumference is attached to a second disc at a short distance
from it.
When the signal apparatus is to be used on board ship, the second
disc has projecting downwards from its centre a stem suitable for being
dropped into sockets, which may be fixed to the ship on either side and
at the stem and stern, so that the lantern may be set up in whichever
position may at any time be most suitable for signalling from. The
handles which are attached to the inner tube and rod project out
between the discs before mentioned at the lower end of the stem.
The tubular stem may be of any desired length, so as to elevate the
lantern to any desire extent above the man who is to work the handles
at its lower end.
By the above-described arrangement a very cheap and simple apparatus
is obtained, suitable for signalling by flashes of light of various colors,
so that signals may be transmitted at night by the international code,
either from one ship to another, or between a ship and land, in the same
manner as day signals are transmitted by different colored flags.
For an all-round light, such as is required for signalling to several
vessels at one time, as in squadron sailing, in place of employing revolving

page_text: screens we employ screens which may be raised and lowered to bring
either one or other of them into action, there being a separate screen for
each colored light, and a dark screen to shut off the light altogether.
Each screen is attached to a rod by which it can be raised and lowered.
The rods are carried down parallel with the stem carrying the lantern,
and at their lower ends they may be provided with handles by which
they can be raised and lowered, or other mechanism for raising and
lowering the rods may be employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Sir William Mitchell and John Joseph Mayo in
the Great Seal Patent Office on the 22nd November 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, Sir
WILLIAM MITCHELL, Knight, of 54, Gracechurch Street, London, and
JOHN JOSEPH MAYO, Esquire, of Benhilton, Sutton, Surrey, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of May, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said Sir William Mitchell and John Joseph
Mayo, Her special license that we, the said Sir William Mitchell and
John Joseph Mayo, our executors, administrators, and assigns, or such
others as we, the said Sir William Mitchell and John Joseph Mayo,
our 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 "In-
PROVEMENTS IN SIGNAL APPARATUS FOR GIVING FLASHES OF LIGHT OF, DIFFERENT
COLORS," upon the condition (amongst others) that we, the said Sir
William Mitchell and John Joseph Mayo, our executors or adminis-
trators, by an instrument in writing under our or their hands and seals,
or under the hand and seal of one of us or them, should particularly

page_text: Joseph Mayo, do nereby 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 improve the construction of signal
apparatus adapted for giving flashes of light of different colors, more
especially for signalling with the international code of signals.
Heretofore it has been proposed to construct lanterns with two internal
screens, each capable of being revolved by handles either at the sides
or top of the lantern. One of these screens has carried glasses of one
or more colors, so that either one or other colored glass can by turning
the screen be brought behind the lens of the lantern and govern the
color of the light; the other screen has been a "dark screen," which
could be turned into a position to cut off all passage of light to the lens.
According to our Invention we mount upon the top of a hollow stem
a lantern fitted as above described with two internal screens. The
bottom of the lantern is at its centre attached to the top of the hollow
tubular stem, and in order to be able to revolve the screens two concentric
tubes, or a tube and rod passing up through the stem, are employed.
One tube is attached at its upper end to the bottom of one of the
revolving screens, whilst the other tube or the rod is attached to the
bottom of the other revolving screen; and to the lower end of the tube
and of the rod handles are attached, by which they can be turned
together with the screens carried by them. The bottom of the tubular
stem which carries the lantern is fixed to the centre of a disc, which at
its circumference is attached to a second diso at a short distance from
it. When, the signal apparatus is to be used on board ship, the second
disc has projecting downwards from its centre a stem suitable for being
dropped into sockets or gimbles, which may be fixed to the ship on
either side and at the stem and stern, so that the lantern may be set
up in whichever position may at any time be most suitable for signalling

page_text: from. The nandies which are attached to the inner tube and rod project
out between the discs before mentioned at the lower end of the stem.
The tubular stem may be of any desired length, so as to elevate the
lantern to any desired extent above the man who is to work the handles
at its lower end.
By the above-described arrangement a very cheap and simple apparatus
is obtained suitable for signalling by flashes of light of various colors,
so that signals may be transmitted at night by the international code
either from one ship to another, or between a ship and land, in the same
manner as day signals are transmitted by different colored flags.
The Drawings hereunto annexed shew a signal apparatus constructed
as above described. Figure 1 is a side elevation of the apparatus, and
Figure 2 is a horizontal section of the same, taken on the line 1, 1,
Figure 1. Figure 3 is a horizontal section taken on the line 2, 2,
Figure 1, and Figure 4 is an under side view of the upper disc F.
A is the outer casing of the lantern fastened by screw pins and
thumb nuts a to a disc b, which is screwed on to the top of the tubular
stem B. Standing up from the disc b is a pin b¹ which is to carry the
lamp C with its reflector. Any suitable kind of lamp or illuminating
apparatus may be employed. Within the outer casing A are two revolving
screens D and E; one is a dark screen which can be turned into a
position to cut off the passage of light from the lantern, and the other
carries a green and also a red glass or glasses, or other colors might
be used. The discs which form the bottoms of the two screens have
slots cut through them for the pin 6¹ to pass through. These slots are
of sufficient length to allow each screen to be turned to the requisite
extent. The tubular stem B at its lower end screws into a socket on
the disc F. The screen D, which is the dark screen, is connected to
the top of a tube d, which passes down through the stem B, and has
a handle D* attached to it at its lower end. The screen E which carries
the colored glasses is similarly connected to a rod or tube e passing
down through the tube d, and has a handle Ex attached to its lower
end. The disc F, as shewn by the Drawings, has a projection F* upon
it, which rests on the lower disc G, and is connected to it by bolts, as
shewn by the Drawing. A rod or tube H screws into a socket on the

page_text: under side of this disc and forms a stem, which may be dropped into
sockets or gimbles wherever the lantern is to be set up, or if the lantern
is not required to be movable the disc G might be otherwise secured
wherever it is desired to set up the lantern.
When signalling by the apparatus above described any desired number
of consecutive flashes, either of a white, red, or green light, may be given.
When flashes of white light are to be given the handle E* is turned into
the position shewn at Figures 1 and 3, and flashes of light are given
by turning away the dark screen by its handle D* from behind the lens
of the lantern (in which position it is shewn in the Drawing), and then
again turning it back to again shut off the passage of light; any number
of flashes may be thus given. To give flashes of red light the red glass
of the screen E is brought behind the lens by turning the handle E* to
the left side, until it comes against the stop F, and flashes of light are
then given by working the handle D* as above explained. If flashes of
green light are to be given the handle Ex is similarly turned in the
opposite direction, that is to say, to the right, until it comes against the
other side of the stop F¹.
For an "all round" light, such as is required for signalling to several
vessels at one time, as in squadron sailing, in place of employing
revolving screens we employ screens which may be raised and lowered
to bring either one or other of them into action, there being a separate
screen for each colored light, and a dark screen to shut off the light
altogether. Each screen is attached to a rod by which it can be raised
and lowered; the rods may be carried down parallel with the stem
carrying the lantern, and at their lower ends they may be provided with
handles by which they can be raised and lowered; or other mechanism
for raising and lowering the screens may be employed to act from the
bottom or top of the lantern.
To transmit signals by flashes of different colored light we employ
consecutive flashes of light of one or more colors, in the manner shewn
by the following table, to represent the several signal letters for the
international code which is now in general use. By an arbitrary com-
bination of two, three, or four of these letters (which are represented by
flags during the day and by flashes of light at night as now proposed)

page_text: universal signals are made by ships at sea, and by signal stations on
shore which have the same signification in all languages.
(Q) 1 flash green
(interval equal to 3 flashes).
(H) 6 flashes white
(interval equal to 3 flashes).
(M) 4 flashes red
(interval equal to 3 flashes).
(F) 4 flashes white
(interval equal to 3 flashes,
and then open red light as
directed in the instruc-
(P) 6 flashes red
(interval equal to 3 flashes).
(Q) 1 flash green
(interval equal to 3 flashes).
(G) 5 flashes white
(interval equal to 3 flashes,
and then open red light
as directed in the instruc-
tions).
The apparatus herein-before described for signalling by flashes of
light is applicable not only for signalling by the code or system above
described, but also by other codes or systems for transmitting signals
by flashes of different colored light.

page_text: Having thus described the nature of our Invention, and the manner
of performing the same, we would have it understood that what we
claim as our improvements in signal apparatus for giving flashes of light
of different colors is,―
1. The combination of a signal lantern such as herein described, with
a hollow tubular stem up through which pass tubes or a tube, and rod,
for revolving the screens of the lantern by means of handles substan-
tially as herein described.
"
2. The combined arrangement of "all-round signal apparatus
substantially as herein described.
In witness whereof, we, the said Sir William Mitchell and John
Joseph Mayo, have hereunto set our hands and seals, this
Twentieth day of November, in the year of our Lord One thousand
eight hundred and seventy-one.
WILLIAM MITCHELL. (L.S.).
JNO. J. MAYO.
(L.S.)