IMPROVE- MENTS IN ACOUSTIC TELEPHONE LINES
Year: 1885

page_text: I, ARTHUR LE NEVE FOSTER of East Hill, Wandsworth, in the County of
Surrey, Electrician do hereby declare the nature of my invention for "IMPROVE-
MENTS IN ACOUSTIC TELEPHONE LINES to be as follows:-
The line for connecting acoustic telephones such as described in patent N° 9050
-1884 I construct of a stranded steel or other suitable wire preferably of a
stranded wire consisting of three strands having a short lay. The wire is supported
between the instruments at each end of the line by the usual attachments either.
fixed to posts or other supports in the usual manner.
By employing a wire constructed as above described I find greater clearness of
speech is obtained more especially when long spans of wire have to be run.
I sometimes in order to prevent a ringing sound that is set up in the instrument
more especially where very short lengths of wire are run in the inside of buildings.
& cover the wires at short intervals with fine rubber tube, gutta percha, cotton,
hemp, or other substances that are bad conductors of sounds the employment of
which I find adds considerably to the clearness of speech. Or the stranded wire as
above described may consist of a strand made up in part wire and part hemp
or similar substances.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: I ARTHUR LE NEVE FOSTER of East Hill, Wandsworth in the County of
Surrey, Electrician do hereby declare the nature of this 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 has for its object improvements in acoustic telephone lines.
The line for connecting acoustic telephones such for example as are described in
the Specification of a Patent N° 9050 in the year 1884 I construct of a stranded
steel wire. I use by preference a strand of three N° 25 B. W. G. wires equal to
023" in diameter each wire these are tinned and laid together, the lay making one
complete turn in about one inch.
The strand which should be strained between the instruments at each end of the
line and supported where necessary by the usual attachments either on posts or
other supports.
By employing a strand as above described in place of a single wire as heretofore
I find greater clearness of speech is obtained more especially over long spans.
In place of strands of steel wire strands of other metal wires may be used but
I prefer the use of steel on account of its high tensile strength.
It is found in practice that the short connecting wires within buildings especially
are apt to set up ringing sounds in the instrument. In order to prevent this
I cover the wires either throughout their length or at parts with thin india rubber
lapped or otherwise covered around it; or in place of india rubber I may employ
gutta percha or it may be a yarn of cotton or hemp or other material a bad
conductor of sound. India rubber in the form of a fine tube I prefer to use,
it damps any musical vibrations set up in the wire and adds considerably to
clearness of speech through the instrument.
I can use for the same purpose a strand such as that employed for the long line
wire but with hemp or fibrous yarns laid into the strand together with the wire or
lapped on the outside of it.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. An acoustic telephone line in which the instruments are connected by a
strained strand of steel or other metal wire substantially as described.
2. An acoustic telephone line composed either wholly or in part of strained wire
covered with india rubber, gutta percha, fibrous material or other bad conductor of
sound, whereby musical undulations upon the line wire are damped substantially
as described.
3. The use in acoustic telephone lines of stranded wires substantially as
described.
Doted this 3rd day of April 1886.