IMPROVEMENTS IN APPARATUS FOR TELEGRAPHING BY MEANS OF REFLECTED
Year: 1874

page_text: LETTERS PATENT to Henry Christopher Mance, of 5, Magdala Terrace,
Manor Road, Brockley, in the County of Kent, for the Invention of
"IMPROVEMENTS IN APPARATUS FOR TELEGRAPHING BY MEANS OF REFLECTED
"
PROVISIONAL SPECIFICATION left by the said Henry Christopher
Mance at the Office of the Commissioners of Patents, with his
Petition, on the 3rd October 1874.
I, HENRY CHRISTOPHER MANCE, of 5, Magdala Terrace, Manor Road,
Brockley, in the County of Kent, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN APPARATUS FOR TELEGRAPHING BY MEANS
OP REFLECTED LIGHT," to be as follows:-
:-
This Invention has for its object improvements in apparatus for
telegraphing by means of reflected light.
I arrange a mirror in such manner that I am able to reflect flashes of
sunlight with such case, quickness, precision, and accuracy, both as

page_text: regards direction and duration as to afford a ready means of communi
cation between stations however remote (providing the rotundity of the
earth or other obstacle does not intervene).
The apparatus is specially adapted for use between changing positions
and therefore for military purposes in the field. The apparatus permits
of the use of the Morse alphabet, which as the best code of signals
extant is usually employed.
The instrument is constructed as follows:-A circular mirror is sup-
ported on pivots in a semicircular frame, at the bottom of which is a
socket. The latter is furnished with a thumbscrew to secure the mirror
and frame when placed on a cone forming part of a base plate which is
able to turn on a brass bed. The bed serves to support the base plate
and mirror and forms the stand of the instrument, tripod legs being
attached to it. The mirror and frame can be removed with case from
the cone by loosening the screws so as to permit of their being packed
separately. The base plate revolves easily in the bed on which it rests,
and it can be turned by means of a tangent screw which acts upon the
milled edge of the base plate, the circumference of which is grooved and
cut to receive the threads of the tangent screw. This screw when the
head is pressed outwards is removed from contact with the base plate
which can then be turned round freely and rapidly by the hand.
The branch which supports the tangent screw is permanently screwed
to the side of the bed.
In addition to the mirror frame the base plate carries a lever with the
outer end of which a handle is connected; the handle is upon a rod con-
nected at one end with the lever and at the other with the mirror by
joints. The lever is kept permanently raised by a spring as far as an
adjustable stop will permit. By pressing the handle it will be seen that
the angle at which the mirror is inclined is slightly altered. The rod
connecting the lever and mirror is telescopic and can be clamped at any
length by a screw, or the effective length of the rod can be altered more
slowly by twisting the handle and thus screwing the end of the rod
through a metal ball which works on pivots and secures the rod to the
back edge of the mirror. In signalling the handle is worked like an
ordinary telegraph key by the right hand of the operator, the left hand
being at liberty to control the tangent screw. By means of these adjust-
ments the angle of the mirror may be altered in accordance with the

page_text: changing position of the sun without any interruption to the trans-
mission of signals.
The upper extremities of the tripod legs fit closely into cylindrical
grooves cut into the under side of the brass bed. The legs are attached
to the brass bed and can be clamped fast by means of screws which pass
through the bed and are secured by nuts from the other side. These
nuts are countersunk in the upper surface of the bed so as not to
interfere with the movement of the base plate which rests closely on the
surface of the bed.
The instrument is used in connection with a sighting rod. The rod is
placed ten or twelve yards in advance of the instrument to mark a spot
exactly in a line between the centre of the mirror and the distant station;
it should be made from white wood and may be jointed like a fishing
rod. A metal stud slides along the stick and marks the true line to the
distant station. There is a light cross piece about 9 inches in length
also ajustable and usually about 9 inches below the stud; this cross piece
is to serve as a mark on which to throw the beam of light in setting the
instrument. For convenience in packing the cross piece can be turned
parallel with the sighting rod. A small quantity of the quicksilver is
removed from the centre of the mirror, leaving a space of clear glass
about of an inch in diameter, and a hole is cut in the metal at the
back of the glass to allow of the operator looking through the clear
glass from behind the mirror towards the distant station when adjusting
the sighting stick.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Christopher Mance in the Great Seal
Patent Office on the 3rd April 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
CHRISTOPHER MANCE, of 5, Magdala Terrace, Manor Road, Brockley,
in the County of Kent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of October, in the year
of our Lord One thousand eight hundred and seventy-four, in the

page_text: and frame when placed on a cone forming part of a base plate which is
able to turn on a brass bed. The bed serves to support the base plate
and mirror and forms the stand of the instrument, tripod legs being
attached to it. The mirror and frame can be removed with ease from
the conc by loosening the screw so as to permit of their being packed
separately. The base plate revolves easily in the bed on which it rests,
and it can be turned by means of a tangent screw which acts upon the
milled edge of the base plate, the circumference of which is grooved and
cut to receive the threads of the tangent screw. This screw when the
head is pressed outwards is removed from contact with the base plate
which can then be turned round freely and rapidly by the hand.
The branch which supports the tangent screw is permanently screwed
to the side of the bed.
In addition to the mirror frame the base plate carries a lever, with the
outer end of which a handle is connected. The handle is upon a rod
connected at one end with the lever and at the other end with the mirror
by joints. The lever is kept permanently raised by a spring as far as an
adjustable stop will permit. By pressing the handle it will be seen that
the angle at which the mirror is inclined is slightly altered; the rod con-
necting the lever and mirror is telescopic and can be clamped at any
length by a screw, or the effective length of the rod can be altered more
slowly by twisting the handle, and thus screwing the end of the rod
through a metal ball which works on pivots and secures the rod to the
back edge of the mirror. In signalling the handle is worked like an
ordinary telegraph key by the right hand of the operator, the left hand
being at liberty to control the tangent screw. By means of thesc adjust-
ments the angle of the mirror may be altered in accordance with the
changing position of the sun without any interruption to the transmission
of signals.
The upper extremities of the tripod legs fit closely into cylindrical
grooves cut into the under side of the brass bed. The legs are attached
to the brass bed and can be clamped fast by means of screws which pass
through the bed and are secured by nuts from the other side. These
nuts are countersunk in the upper surface of the bed so as not to
interfere with the movement of the base plate which rests closely on the
surface of the bed.
ן

page_text: placed ten or twelve yards in advance of the instrument to mark a spot
exactly in a line between the centre of the mirror and the distant
station; it should be made from white wood and may be jointed like a
fishing rod. A metal stud slides along the stick and marks the true line
to the distant station. There is a light cross piece about 9 inches in
length also adjustable and usually about 9 inches below the stud. This
cross piece is to serve as a mark on which to throw the beam of light in
setting the instrument. For convenience in packing the cross piece can
be turned parallel with the sighting rod. A small quantity of the quick-
silver is removed from the centre of the mirror, leaving a space of clear
glass about of an inch in diameter, and a hole is cut in the metal at
the back of the glass to allow of the operator looking through the clear
glass from behind the mirror towards the distant station when adjusting
the sighting stick.
In order that my said Invention may be most fully understood and
readily carried into effect I will proceed to describe the Drawings here-
Figure 1 is a front elevation and Figure 2 a side elevation of the
apparatus.
a, a, are the tripod legs (the upper portions only are shewn), they fit
into semi-cylindrical recesses in the under side of the brass bed b, they
are attached and can be clamped with any desirable degree of tightness
by screws and nuts, as is shown at Figures 3 and 4, which represent
respectively a plan and section of the bed 6 with the parts attached to it,
as above stated; formed with or attached to the bed b is a branch, shewn
separately in section at Figure 4*, in which is formed the socket
bearing b¹ to hold a ball formed on the end of the tangent screw c. The
tangent screw may either be provided with a milled head or its stem
may be squared at the end to receive a separate key or handle. In the
centre of the bed is a cylindrical or somewhat conical hole, into which
is accurately fitted a corresponding cylinder or cone d* formed on the
under side of the base plate d. A plan and a side view of the base plate
are shewn at Figures 5 and 6. The base plate d is held down in its
place upon the bed by a screw and washer d'; but it is able to turn freely
and steadily; worm teeth are cut around the edge of the base plate, as
is shewn, and with these the thread of the worm or tangent screw c

page_text: engages the screw, being pressed into contact with the base plate by the
spring c', but the screw can by a slight pressure be pushed back out of
gear to admit, when desired, of the base plate being turned rapidly by
hand; & is a lump formed or fixed on the base plate d, the lever e is
jointed to it; the lever passes through a slot or hole in the cone d³ which
rises in the centre of the base plate; f is a spring which sustains the
lever e, but it can be depressed at pleasure, its play being limited by the
stud d' fixed beneath it in the base plate and the adjusting screw g,
the lower end of which forms a stop, limiting the rise of the lever; to
the outer end of the lever e the lower part of a telescopic connecting
rod is attached by a ball-and-socket or other suitable joint.
The cono in the centre of the base plate receives when the instru-
ment is mounted for use the socket of the mirror frame i, in which is
hung in trunnions the silvered glass mirror k; a front and side view
of the mirror frame and mirror are shewn at Figures 7 and 8.
The mirror shown is circular, but it may be square or of other form.
is a screw for clamping the mirror frame in its place. When it is
screwed home its end enters a groove provided for it in the cone d³. The
mirror and mirror frame are removed and packed in a separate case for
conveyance from place to place. To the top of the mirror frame the nut /
is attached. The nut is formed with trunnions or studs projecting from
it on either side, and these are held (but so as to be able to turn) by the
arms projecting from the mirror frame; or the nut may be held
between the points of pivot screws. The upper part m of the telescopic
connecting rod has a screw thread cut upon it, and it works through the
nut l.
Figures 9 and 10 shew a side view and section of the telescopic con-
necting rod. The lower part his tubular, and the stem m enters into it,
and is clamped in any position by screwing the nut / down the thread
on which it works. This screw is taper, and there are slits in the tube
so that the nut is able to compress and contract it so as to bind the
stem m; or any other simple clamping device, for example, a simple
slider such as is shown at Figure 9*, may be resorted to. h³ is a milled
head, which with other parts connected with it serves as a finger key or its
equivalent. The fingers rest upon it to depress the lever e, and as soon
as the pressure is relieved the spring causes it to return, the mirror
moving with it. The milled head is also used to turn the connecting rod
to vary the inclination of the mirror.

page_text: Figure 11 shews to a smaller scale the sighting rod; it is made in two
parts, and has upon it two sliders n and o. The slider n is to be aligned
with the station to which the signal is to be made, the operator looking
through the sighting hole in the back of the mirror. The slider o carries
a cross bar o' to receive the reflection from the mirror.
In preparing the apparatus for use it is so adjusted that the light
appears on the centre of the cross bar o' when the finger key h² is not
depressed, and so that the depression of the finger key will raise the
reflection to the sight point n, and so render it visible to the station to
which the signals are to be made..
During signalling the adjustment is maintained by slowly rotating the
milled head ² and the tangent screw c.
This can be done without any
interruption of the signals.
The way in which the flashes are combined to communicate by the
Morse code does not require further description.
In order to protect the instrument from rough usage, and to permit of
its easy removal from and use without the tripod, a hollow cylinder or
false bed may be screwed on the bed proper, as shewn by Figures 12 and
13. The upper end of this cylinder is pierced to receive the under side
cone d*, on which and within the cylinder is fixed a plate. The tangent
screw acts on the circumference of this plate, and revolves the base plate
and mirror. The tangent screw and spring are also fixed inside the
cylindrical false bed.
If it is preferred in place of teeth on the edge of the base plate a circle
of teeth may be cut on its under side, a worm or a pinion being made to a
engage with these teeth to rotate the base plate. For a permanent
signalling station the instrument will be mounted on a fixed pedestal in
place of on tripod legs, and the size of the mirror may be increased. The
apparatus possesses the capability, even when stationary, of telegraphing
with equal case in every direction. When required to be used in the a
direction immediately opposite to the sun it is supplemented by a second
mirror. The sun's rays are by the second mirror reflected on to the
mirror attached to the apparatus, and so to the required spot. The
instrument is however specially adapted for use between changing
positions, and therefore for military purposes, in the field, surveying, 3
&c. The alphabet usually employed is the Morse, but any other code may
be used. It is obvious that artificial light may be used when the sun is

page_text: not available. When for any purpose a heliostat is required these
instruments are available.
What I claim as my improvements in apparatus for telegraphing by
means of reflected light is,―
The combination of a mirror with a finger key or its equivalent, and
with apparatus by which the mirror can be rotated and inclined, the
whole being mounted on a suitable stand, and arranged in such manner
that by the action of the finger key or its equivalent light can be flashed
with precision to a distant station, substantially as described.
I also claim the general arrangement of the apparatus, substantially
as described and shewn in the annexed Drawings.
In witness whereof, I, the said Henry Christopher Mance, have
hereunto set my hand and seal, this Sixteenth day of February
in the year of our Lord One thousand eight hundred and seventy-
five.
HENRY CHRISTOPHER MANCE. (L.S.)