IMPROVEMENTS IN SHIPS' PENDULUMS OR CLINOMETERS.
Year: 1881

page_text: LETTERS PATENT to John
Road, Southwark, in the
Short, of 2, Gladstone Street, Saint George's
County of Surrey, Mathematical Instrument
Maker, for an Invention of "IMPROVEMENTS IN SHIPS' PENDULUMS OR
CLINOMETERS.
"
PROVISIONAL SPECIFICATION left by the said John Short at the Office
of the Commissioners of Patents on the 26th July 1881.
JOHN SHORT, of 2, Gladstone Street, Saint George's Road, Southwark, in the
County of Surrey, Mathematical Instrument Maker. "IMPROVEMENTS IN SHIPS'
PENDULUMS OR CLINOMETERS."
This Invention relates to the construction of an instrument called a ship's
pendulum or clinometer, or pendulum alarm, by the use of which the amount of
rolling or lurching of ships at sea may be accurately known either by observation
of the instrument or by a signal from the electric alarm bell attached to the
instrument.
The said Invention comprises the combination of a curved tube of glass connected
to a curved tube of iron or vulcanite, the whole forming together a ring of glass
and iron or vulcanite tubing, more or less circular in shape; this tubular ring is
half filled with mercury, the mercury being visible in that portion of the tubular
ring which is formed of glass.
Attached to the upper part of this tubular ring is a cistern or bottle made of
iron, vulcanite, or other material, into which the whole of the mercury is admitted
by means of a tap when the pendulum or clinometer is not in use, and mercury is
therefore not required in the tubular ring; this ensures that the glass portion of
the ring is not broken in carriage of the pendulum or clinometer, as it certainly
would be if mercury was allowed to remain in it during carriage from place to
place previous to the instrument being mounted in a ship.
The said Invention also comprises the combination of a square frame or case of
wood having a brass scale of graduations on its inner face, each graduation
representing 1° (one degree) of roll or lurch of the ship; the front of this square

page_text: frame or case of wood has one portion of it cut open and a plate of glass inserted,
through which a portion of the curved glass tube with mercury in it is visible
standing against the brass graduated scale, the graduated scale or inner face of the
wood case also being visible through this opening in the front.
The tubular ring of glass and iron, or vulcanite aforesaid, is fitted into this
frame of wood in such a manner that the top of the curved column of mercury
visible in the glass portion of the tubular ring becomes the index point or register
against the brass scale of graduations, and so shews at any moment the angle of
roll or lurch which the ship at sea has taken.
The frame of wood containing the working portion of the pendulum or clino-
meter is about nineteen inches high, fifteen inches wide, and two inches from back
to front, this being found a convenient size, but any larger or smaller sizes and
differing proportions can equally well be made, and are claimed by me under the
description of the Invention aforesaid.
The said Invention also comprises the combination or addition of an ordinary
electric-alarm bell and battery to be attached to the frame of this instrument, or
connected thereto by ordinary electric conducting wires, with the object of giving
notice that the ship has rolled or lurched to a certain before determined angle or
angles.
The sounding of this alarm-bell is secured in the following manner :-A ring of
vulcanite and india rubber tubing of similar shape and construction to the ring
of glass and iron or vulcanite tubing aforesaid is fixed inside the wood frame of the
instrument and partly filled with mercury; wires of copper or other conducting
material are fixed into this vulcanite tube at heights corresponding each to each to
the before determined angles of roll of ship at which the alarm bell is to sound,
and the ends of these wires are connected with one pole of the battery.
The electrical circuit is formed in the following manner-In the bottom part of
the ring of vulcanite and india rubber tubing a wire of copper or other conducting
material is fixed and is in permanent contact with the column of mercury inside that
tubing this wire is carried to one pole of the electro-magnet which works the
alarm-bell, the other pole of the electro-magnet being connected with the battery.
On the ship rolling to the before determined angle at which the alarm-bell is to
sound, the column of mercury in the tube of vulcanite rises until the copper wire
fixed to represent this angle is in contact with the mercury, when the electrical
circuit being formed the alarm-bell sounds, and continues ringing until the ship
has recovered a more level position than that at which the alarm-bell is arranged
to ring.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Short in the Great Seal Patent Office on the 20th January
1882.
JOHN SHORT, of 2, Gladstone Street, St. Georges' Road, Southwark, in the
County of Surrey, Mathematical Instrument Maker. "IMPROVEMENTS IN SHIPS'
PENDULUMS OR CLINOMETERS."
This Invention relates to the construction of an instrument called a ship's
pendulum or clinometer, or pendulum alarm, by the use of which the amount of
rolling or lurching of ships at sea may be accurately known either by observation
of the instrument or by a signal from the electric alarm bell attached to the
instrument.
The said Invention comprises the combination of a curved tube of glass connected
to a curved tube of iron or vulcanite, the whole forming together a ring of glass
and iron or vulcanite tubing, more or less circular in shape; this tubular ring is
half filled with mercury, the mercury being visible in that portion of the tubular
ring which is formed of glass. Attached to the upper part of this tubular ring is
a cistern or bottle made of iron, vulcanite, india-rubber, or other material, into
which the whole of the mercury is admitted by means of a tap when the pendulum
or clinometer is not in use, and mercury is therefore not required in the tubular
ring; this ensures that the glass portion of the ring is not broken in carriage of
the pendulum or clinometer, as it certainly would be if mercury was allowed to
remain in it during carriage from place to place previous to the instrument being
mounted in a ship.
The said Invention also comprises the combination of a square frame or case of
wood having a brass scale of graduations on its inner face, each graduation
representing 1° (one degree) of roll or lurch of the ship; the front of this square
frame or case of wood has one portion of it cut open, and a plate of glass inserted
through which a portion of the curved glass tube with mercury in it is visible
standing against the brass graduated scale, the graduated scale or inner face of
the wood case also being visible through this opening in the front.
The tubular ring of glass and iron or vulcanite aforesaid is fitted into this frame
of wood in such a manner that the top of the curved column of mercury visible
in the glass portion of the tubular ring becomes the index point or register against
the brass scale of graduations, and so shews at any moment the angle of roll or
lurch which the ship at sea has taken.
The frame of wood containing the working portion of the pendulum or clinometer
is about 19 inches high, 15 inches wide, and two inches from back to front, this being
found a convenient size, but any larger or smaller sizes and differing proportions
can equally well be made, and are claimed by me under the description of the
Invention aforesaid.
The said Invention also comprises the combination or addition of an ordinary
electric alarm bell or bells and battery to be attached to the frame of this
instrument, or connected thereto by ordinary electric conducting wires, with object
of giving notice that the ship has rolled or lurched to a certain before determined
angle or angles.
The sounding of this alarm-bell is secured in the following manner :-A ring of
vulcanite and india-rubber tubing more or less circular in shape and of similar
construction to the ring of glass and iron or vulcanite tubing aforesaid is fixed
inside the wood frame of instrument and partly filled with mercury, wires of iron
or other conducting material are fixed into this vulcanite tube at heights
corresponding each to each to the before determined angles of roll of ship at which
the alarm bell is to sound, and the ends of these wires are connected with one pole
of the battery.
To arrange at pleasure the sounding of alarm bell for different angles of roll
of the ship, a frame of brass is fitted to this ring of vulcanite and india-rubber

page_text: tubing, having two arms, in whose ends pieces of straight iron wire are fixed; this
iron wire passes into and down the straight part of this ring of tubing, the frame
of brass being raised and lowered by a rack and pinion. As the frame of brass is
raised or lowered the ends of iron wires fixed in the two arms of the brass frame
are at heights corresponding each to each to the before determined angle of roll-of
the ship at which alarm-bell is arranged to sound, and these iron wires are
connected with one pole of the battery by a copper wire soldered to brass frame
and carried on to the battery.
The angle of roll of ship at which the alarm-bell will sound is seen by the dial
or front of the wood frame; this dial is read by an index which is fixed to the
brass frame and moves with it when it is raised or lowered by rack and pinion.
The electrical circuit is formed in the following manner:-In the bottom part
of ring of vulcanite and india-rubber tubing a wire of iron or other conducting
material is fixed, and is in permanent contact with the column of mercury inside
that tubing this wire is carried to one pole of electro-magnet which works
the alarm bell, the other pole of the clectro-magnet being connected with the
battery. On the ship rolling to the before determined angle at which alarm-bell is
to sound, the column of mercury in the tube of vulcanite rises until the iron wire
fixed to represent this angle, or the piece of straight iron wire fixed in the ends of
the two arms of brass frame, one in contact with the mercury, when the electrical
circuit being formed alarm-bell sounds and continues ringing until the ship has
recovered a more level position than that at which the alarmn-bell is arranged
to ring.
DESCRIPTION OF DRAWING.
In the accompanying Drawing, Figure 1 shews the pendulum or clinometer as
ready for fitting on a ship. A is the wood frame of instrument; B, the alarm-
bell fixed to the instrument, but can be placed away from it in any part of the
ship; C, the curved tube of glass, a portion of the tubular ring, in which is seen
the column of mercury, standing against the brass scale of graduations; D, the dial
on front of wood frame which shews angle of roll of ship at which alarmn-bell will
sound; S, the movable index pointing to this angle at which bell will sound; R,
the middle-head, a part of the rack motion which moves the index S; Q, Q: Q,
are three brass ears for fixing instrument by screws to any part of the ship
determined on.
°
Figure 2 shews the inside of wood frame; K, K, K, is the ring of vulcanite and
india-rubber tubing in which the iron wire is fixed, or-the two arms of the brass
frame work, and is partly-filled with mercury; G, G, G, is the brass frame which
-is-moved by the rack motion; H, H, are the two arms of this brass frame, having
fixed in their ends the two iron wires O, O; R, R, is the rack motion which moves
this frame; N, N, are the copper wires forming connection between the mercury
and the electro-magnet, and between the brass frame and the battery; T is the
bottle or cistern which holds the mercury when the pendulum or clinometer is not
in use.
The battery is not shewn in Drawing, but is the usual kind employed for working
electric bells, and can be placed near alarm-bell or away from it in any part of the
ship, connected to it by conducting wires.
In witness whereof, I, the said John Short, have hereunto set my hand and
seal, the Thirteenth day of January, in the year of our Lord One
thousand eight hundred and eighty two.