IMPROVEMENTS IN TELEGRAPHIC COMMUNICATION BY PNEUMATIC MEANS, AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1867

page_text: PROVISIONAL SPECIFICATION left by Alexander Prince and Alexander
Charles Montague Prince at the Office of the Commissioners of Patents,
with their Petition, on the 16th October 1867.
We, ALEXANDER PRINCE and ALEXANDER CHARLES MONTAGUE PRINCE, both
of the Office for Patents, No. 4, Trafalgar Square, Charing Cross, in the
County of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN TELEGRAPHIC COMMUNICATION BY PNEUMATIC MEANS, AND IN
THE APPARATUS EMPLOYED THEREIN," to be as follows:-
This Invention relates to certain improvements in effecting telegraphic
communication by means of pneumatic pressure or exhaustion, or both
combined, and in the apparatus to be employed therein, the object of the
Invention being to accomplish a system of signals by means of pressure or
any suitable
withdrawal of air acting on an indicating or signalling dial of
description.
In order to carry the Invention into effect reservoirs of compressed air are
employed in conjunction with tubes, and signalling dials or other apparatus
capable of being acted upon by atmospheric pressure; or if the signal apparatus
is desired to be operated by a partial vacuum or exhaustion the reservoirs
would be exhausted accordingly. The air may be compressed by force pumps
or other known means. The tubes may be laid down separately from place
to place, or a main tube may be used to a central station, from which other
tubes may be conducted to surrounding localities. Each end of the tubes is
to be provided with an apparatus for compressing or withdrawing air in the

page_text: tubes, and also with a signalling apparatus consisting of a dial with letters and
figures or other indications or codes of signals marked thereon, around and
over which a needle or indicating point is caused to travel by the pressure or
withdrawal of air to the letters required, so as to telegraph or signal words or
figures, so that the dials at each end of the tube will both be acted upon
simultaneously by the air, and both indicate the same signal. The air is
admitted from the reservoirs to the tubes by means of handles and valves, and
withdrawn by outlet valves to reduce the pressure.
In case it should be required to send a telegraphic signal by means of one
main tube to a central locality, and thence to a branch or branches without
the intervention of a station, a self-acting apparatus may substituted capable
of controlling or regulating the passage of the air from the main tube through
any one of the branch tubes connected to such apparatus. This consists of a
vertical cylinder provided with a piston and rod passing through a stuffing
box; the space between the piston and top of cylinder containing a belical
spring or springs, which bear upon the piston and tend to force it downwards..
A series of openings are formed in a vertical line one above the other in the
cylinder, from which the branch pipes are conducted to any places desired,
Each of these openings are secured by clack valves bung from their upper
edges and shutting against the openings; they are provided with bell-orank
levers or arms, which are acted upon by the ascent and descent of the piston
by means of a hinged tooth or catch hinged to the lower edge of the piston,
and kept in a horizontal position by means of a flat spring below it, therefore
as the piston rises the curved or upper edge of the catch comes in contact
with the bell-cranks, which, having a slight amount of backward play permit
of the passage of the catch without acting on the clack valves. Supposing
it is necessary to send a communication through a branch tube the pressure
of the air from the departure station must be regulated by means of the
pressure dial to the extent necessary to elevate the piston against the action of
the spring, so that the catch will rise just above the valve of the branch tube;
the pressure is then withdrawn and the piston descends, but the catch coming
over the bell-crank or other lever of the clack valve throws it open inwardly
to the cylinder, and maintains it open, all the other valves being closed; then
the signalling is carried on between the two stations; when the communication
is finished the main or full pressure is again put on, the piston rises to the top
of the cylinder, and the catch travels into an oblique groove cut in the cylinder,
and the pressure being withdrawn the piston descends freely to the lower part
of the cylinder by the passage of the catch down a vertical groove free of but
close at the side of the valves, coming back by another oblique groove at the

page_text: bottom of the cylinder in line with the valves ready to open any valve and
branch required.
When the apparatus is not in use a telegraphic signal can be sent through
it to the main station from any branch, because all the valves open inwards,
and a communication is made between the apparatus and the main tube
independently of the piston; when such signal comes, indicating the branch,
the piston of the apparatus is raised to the proper valve, keeping it open for
the interchange of signals.
Other equivalents may be used for the cylinder, piston, and spring, a
dome on the principle of a gasometer may be employed, or accumulative
weights may be substituted for the spring or springs; or slides may be used
instead of valves.
The pressure to raise the piston will vary from one to several pounds to the
inch, but the pressure for the telegraphic signals will of course be comparatively
slight.
The telegraphic signals are to be given by means of a needle or pointer
travelling round a dial with letters or figures thereon, such needle being
actuated by the ordinary means used in aneroid barometers or other equivalent
means. The operator regulates the pressure by a handle till the needle
arrives on the letter or figure, and it will therefore follow that the same signal
will be given at the extremity of the tube and brauch.
Should the exhaust principle be used in lieu of pressure the valves and
indicators must be arranged accordingly.
The main object of this Invention is to substitute pneumatic telegraph
signals conveyed through tubes to indicating apparatus of any suitable
description capable of being actuated by pressure or withdrawal of air in such
tubes, in lieu of the ordinary electric system of telegraphing. This pneumatic
system, when rigid tubes are used, is especially applicable to land telegraphic
purposes, but where it is desired to apply the Invention to submarine
telegraphs, or to submerge the tube under water, it will then be desirable to
use flexible waterproof tubes and suitable apparatus.