IMPROVEMENTS IN THE MODE OF COMMUNICATION BY MEANS OF SPEAKING TUBES, APPLICABLE TO APPARATUS FOR SUPPORTING RESPIRATION UNDER WATER
Year: 1874

page_text: LETTERS PATENT to Robert Applegarth, of No. 63, Queen Street,
Cheapside, in the City of London, Agent, for the Invention of
"IMPROVEMENTS IN THE MODE OF COMMUNICATION BY MEANS OF SPEAKING
TUBES, APPLICABLE TO APPARATUS FOR SUPPORTING RESPIRATION UNDER
WATER."A communication from abroad by Louis Denayronze, of
No. 3. Boulevard Voltaire. Paris. France.
•
PROVISIONAL SPECIFICATION left by the said Robert Applegarth
at the Office of the Commissioners of Patents, with his Petition,
on the 10th June 1874.
I, ROBERT APPLEGARTII, of No. 63, Queen Street, Cheapside, in the
City of London, Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN THE MODE OF COMMUNICATION BY MEANS OF SPEAKING
TUBES, APPLICABLE TO APPARATUS FOR SUPPORTING RESPIRATION UNDER WATER," a
communication to me from abroad by Louis Denayronze, of No. 3,
Boulevard Voltaire, Paris, France," to be as follows :—
This Invention relates to the transmission of sound through speaking

page_text: tubes to or from divers and others employed under water, and its object is
to enable communications to be made by and with divers or others when
so employed by means of a single tube and simple apparatus.
The ordinary communication by means of speaking tubes is effected
by the person desirous of speaking opening his end of the tube and
attracting the attention of the person at the other end, who also
opens
that end of the tube, and the person desirous of speaking then applies
his mouth to the opening of the tube, and makes his communication,
the air meanwhile flowing through the tube. This method is inapplicable
to persons working in a diving helmet, as the opening of the end of the
tube communicating with the helmet, whether by a stop-cock or otherwise,
is inconvenient and difficult to the person wearing the helmet, and when
the tube communicating with the helmet is open at both ends the air
supplied to the diver would escape.
These difficulties are obviated in my Invention by making available
the vibration produced by the voice of the metallic surface of the helmet
and in collecting under a cap or dome the undulations of sound produced
by these vibrations, whence they are transmitted to a distance by means
of an ordinary tube.
The apparatus consists of a speaking tube terminating at the helmet
with a cap or dome fixed outside the helmet upon some convenient part of
it, which forms with the portion of the helmet which it covers a hollow
space, and protects from contact with the water the metallic surface of
the helmet so covered.
The working of the apparatus is as follows:-If the person wearing
the helmet desires to communicate with the attendant by speaking in his
helmet he puts in vibration the air enclosed in it, and these vibrations
are communicated to the metallic surface of the helmet. The undulations
of sound created by the vibration of that part of the helmet which is
exposed to the water escape into it and are lost, but those caused by that
part of the helmet under the cap or dome are transmitted through the
tube to the car of the attendant, which placed at the end can perceive
them. If, on the other hand, the attendant wishing to communicate
with the person wearing the helmet speaks with his mouth at the
opening of the tube the undulations of sound produced by his voice
enter the tube, go down, and strike upon the metallic surface of the
helmet enclosed by the cap or dome, causing it to vibrate, and the wearer
of the helmet perceives the sounds.

page_text: A result of a similar description may be obtained by terminating the
speaking tube with any vibrating surface whatever, and placing it against
any part of the surface of the helmet, but this is less perfect, as the
interposition of the second surface between the tube and the helmet
would tend to weaken the sound. The principle is the same, namely,
that the metal helmet serves as a medium for the sonorous vibration of
the air.
The merits of the Invention are, that communication may be held by
or with divers and others when at work by means of a single tube and a
simplo contrivance; that the diver or other person can communicate
with his attendant by simply speaking in his helmet without requiring
to manage, or control any appliance whatever; that there is no opening
into the helmet required, and therefore no risk is incurred of the escape
of air from it.
I also propose, in order to further simplify the appliances used by
divers, to make the signal line hollow of india-rubber tubing or other
proper material, and using it as the speaking tube in connection with
my said Invention.
Having thus described the nature of this Invention, and in what
manner the same is to be performed, I claim,-
First. The utilization of the vibration of the metal surface of diving
and other similar helmets so as to transmit from one side of the surfaco
the undulations of sound which strike it upon the other side.
Second. The helmet doubled with a thin metal sheet intended to
vibrate so as to transmit sound to or from the wearer of the helmet, and
the exclusive right of applying it to every system of diving or other
similar helmet now in use or hereafter to be used.
Third. To guard against any infringement which would seek to vary
or alter the Invention by making the speaking tube with a funnel which
might be attached to or detached from the helmet, terminating by a
metal plate of any shape, or of clastic matter, skin, or other vibrating
surface whatever.
Fourth. The utilization of the signal or life line as a speaking tube by

page_text: and of an Order of the Lord Chancellor, by the said Robert Apple-
garth in the Great Scal Patent Office on the 24th December
1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
APPLEGARTH, of No. 63, Queen Street, Cheapside, in the City of London,
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of June, in the year of our
Lord One thousand eight hundred and seventy-four, in the thirty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Robert Applegarth, Her special licence that I,
the said Robert Applegarth, my executors, administrators, and assigns,
or such others as I, the said Robert Applegȧrth, 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
THE MODE OF COMMUNICATION BY MEANS OF SPEAKING TUBES, APPLICABLE TO
APPARATUS FOR SUPPORTING RESPIRATION UNDER WATER," communicated to me
from abroad by Louis Denayronze, of No. 3, Boulevard Voltaire, Paris,
France, upon the condition (amongst others) that I, the said Robert
Applegarth, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, 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 Robert Applegarth, 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:-
This Invention relates to the transmission of sound through speaking
tubes to or from divers and others employed under water, and its object

page_text: Fourth. The utilization of the signal or life line as a speaking tube by
making it hollow.
In witness whereof, I, the said Robert Applegarth, have here-
unto set my hand and scal, this Tenth day of December, in
the year of our Lord One thousand eight hundred and seventy-
four.