IMPROVEMENTS IN SIGNAL LANTERNS
Year: 1872

page_text: LETTERS PATENT to Sir Francis Blackwood, Baronet, Commander,
Royal Navy, of the Marlborough Club, Pall Mall, in tho County of
Middlesex, for the Invention of "IMPROVEMENTS IN SIGNAL LANTERNS."
Sealed the 29th October 1872, and dated the 11th May 1872.
PROVISIONAL SPECIFICATION left by the said Sir Francis Blackwood
at the Office of the Commissioners of Patents, with his Petition,
on the 11th May 1872.
I, Sir FRANCIS BLACKWOOD, Baronet, Commander, Royal Navy, of
the Marlborough Club, Pall Mall, in the County of Middlesex, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN SIGNAL
LANTERNS," to be as follows:-
The object of this Invention is to enable two or more signal lights to
be shewn from one lamp. For this purpose, if two signal lights are
required to be shewn, the light from a lamp is thrown by a bull's
cyc lens or by a reflector on to two flat reflectors, inclined at an angle
of 45° to the stream of light thrown from the lamp. The light is
thereby reflected in two opposite directions, and is received on to two

page_text: other reflectors again, inclined at an angle of 45° to the line of light, and
the light is thereby thrown in two parallel streams through two glasses
at any desired distance apart from one another, and which may be of
any color desired. These glasses and the inclined reflectors are carried
by a tube or case, which is also formed so as to receive the lamp
opposite to the two central inclined reflectors, so that the lamp can
readily be removed from the tube or case for the purpose of cleaning.
In a similar manner if three or more signal lights are required to
be shewn the light from the lamp is first thrown on to three or more
inclined reflectors, and then by other reflectors through three or more 1
glasses, which may either be of the same or different colors.
In the case of the side lights for steam ships, I arrange the lanterns
so as to be capable of shewing two lights of the same color one above
the other; the tube or case is in this case placed vortically. In front
of the upper glass I mount a screw, which is connected by cords or 1
otherwise to the tiller ropes or steering apparatus in such manner that
when the rudder is moved over in one direction the screen is moved
away from in front of the glass, but when the rudder is central or moved
over in the opposite direction the screen will be in front of the glass and
only the lower light will be visible. By this means when the rudder is 2
in a central position a red light will as usual be shewn on one side of tho
vessel and a green light on the opposite side, but when the rudder is
turned over in one or other direction, either two green or two red lights
will be shewn from one or other side of the vessel, according to the
direction in which the rudder is put over, and thus when the vessels are 2
approaching one another, each will know in what direction the helm of
the other is acting.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Sir Francis Blackwood in the Great Seal Patent
Office on the 11th November 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Sir
FRANCIS BLACKWOOD, Baronet, Commander, Royal Navy, of the Marl-
borough Club, Pall Mall, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of May, in the year
of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Sir Francis Blackwood, Her
special license that I, the said Sir Francis Blackwood, my executors,
administrators, and assigns, or such others as I, the said Sir Francis
Blackwood, 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 LANTERNS," upon the condition (amongst
others) that I, the said Sir Francis Blackwood, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the naturo
of the said Invention, and in what manner the same was to be per-
formed, 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 Sir Francis Blackwood, 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 improvements in signal lanterns.
For signalling purposes it is often required to shew simultaneously
two, three, or more lights of various colors, and variously arranged, and
capable in some cases of being independently screened from view, as for
example in the case of railway signal lights, and of slips' lights.

page_text: For ships' lights I show in addition the ordinary red and green lights
on the port and starboard sides, two other lights under these, and which
are under the control of the helm, so that they are exposed only when
the helm is put over to port or starboard, but screened when the helm is
amidship or nearly so. In these cases I apply reflectors in such manner
as to obtain from a single lamp flame two or more visible lights, which
may be of different colors, and may be separately screened.
In the annexed Drawing, Figure 1 is a sectional view of a ship's
double light lantern. a is a good lamp, of ordinary construction, with a
bull's-eye in front and a concave reflector behind the flame. This lamp
throws into the tube b an approximately parallel beam of light. A
portion of this beam passes directly through the red glass c and serves as
the ordinary port light of the ship. Another portion of the beam of
light is intercepted by the mirror d and thrown downwards on to the
second mirror e, which reflects it out through the glass at the end of the
tube f. g is a screen in front of the mirror e, as shewn in the Drawing;
it is so placed as to allow the light to pass freely, but when turned one
quarter round it stops the whole of the light reflected by the mirrors.
The screen is controlled by the tiller in any suitable manner; the
most convenient is to cause the tiller when put over to make an electric
contact, and so to excite an electro-magnet placed near the lantern and
connected with the screen. Or in place of thus controlling a screen 7,
the mirror & may be part controlled by the tiller. When the helm is
put over the mirror will be thrown, as already described, into the position
in which the Drawing shews it, that is to say, into a position at an angle
of 45 degrees to the beam of light, but when the helm is amidship the
mirror takes a position parallel to the boam. This arrangement has the
advantage of obstructing very little of the light of the lamp, except at
the times when the helm is put over and a second light is required to
be shewn.
Figure 1 shews another method of obtaining the second light, a
la lane being aukatituted from blaa vallaton at the book¿Lo 1…….

page_text: The Drawing shews the red screen in front of the upper light, the green
in front of the lower light, and the middle light being unscreened appears
as a white light. Similarly, three or other number of lights may bo
shewn from the same lamp in the other direction along the line, another
bull's-eye being placed on the other side of the lamp flame.
Figures 3 illustrate the adaptation of my Invention to a lantern to
shew the tail lights of a train. In this case the lamp a has two bull's-
eyes, one on either side of the flame, throwing two beams of light through
the tubes b and c, and cach of these beams is made to shew two lights,
one behind and the other forward to the engine driver by means of
reflectors d, d. The lamp has also a concave reflector over the flame,
which throws the light down the vertical tubo e, at the bottom of which
is an inclined mirror, which throws the light forward through the glass f.
The oil vessel of the lamp is at a distance, so that only an oil pipe to the
burner intercepts a small portion of the light reflected downwards. In
a similar manner it is obvious that other arrangements of lights may be
shown from a single flame, so as to distinguish the trains the one from
the other.
What I claim is the construction of signal lanterns suitable for ships,
0 railways, and railway trains, and for other such-like uses, substantially
as described.
In witness whereof, I, the said Sir Francis Blackwood, have hereunto
set my hand and seal, this Sixth day of November, in the year of
our Lord One thousand eight hundred and seventy-two.