степу модный for Transmitting Sound Vibrations Existing in or Communi- cated through the Earth.
Year: 1886

page_text: шрготешению гог геторцовые дррагат, степу модный
for Transmitting Sound Vibrations Existing in or Communi-
cated through the Earth.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake, & Co. Patent Agents,
Southampton Buildings, in the County of Middlesex, 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 consists in the combination of a microphone with an apparatus
adapted for insertion into the earth. The microphone being influenced by any
sound vibrations existing in the ground correspondingly modifies an electrical
current conducted through it and causes said vibrations to affect a receiving
telephone and so to be transmitted to the ear of a listener.
Inasmuch as sound vibrations are better conducted through a solid body such as
earth, than through air, it follows that a microphone inserted in earth at a given
point is capable of being influenced by sound vibrations existing in the ground
anywhere over a large area and hence the instrument furnishes a means of
recognizing the presence and character of such vibrations. It is proposed practically
to employ the instrument hereinafter described for military purposes to which its
construction renders it especially suitable. A number of such instruments dis-
posed for example along a picket line or adjacent to a fortification will reveal the
approach of an enemy by enabling foot falls or other noises to be distinctly heard
at the receiving telephone. So also, the instrument will reveal the presence of
persons working at subterranean mines, and in this way it becomes an important
and valuable safeguard against surprise and sudden attack.
In the accompanying drawings,
Figure 1 is a vertical section of the instrument to which the name "microphonic
detector" is given.
Figure 2 shows the instrument inserted in the earth.
Figure 3 is an illustrative view indicating generally how the instrument is
applied to the guarding of a road adjacent to a fortification for example. In the
several drawings similar letters of reference indicate like parta.

page_text: A is a metal tube. To the lower end of said tube is secured an auger point B.
To the upper end is affixed a wooden handle C. Within the tube A is secured, in
any suitable manner, a cylindrical box or case D of hard rubber or other non con-
ducting material. Within said case are two blocks E and F, of carbon. Said
blocks closely fit within the case. In each block is a shallow recess to receive the
ends of the intermediate carbon block G. The blocks E, F, G thus form a
microphone of known construction.
To the handle A are secured two binding posts 1 and 2. A wire a from binding
post 1 communicates with carbon block F, and a wire b from binding post 2 com-
municates with carbon block E. Battery is connected to binding post 2 and line
to binding post 1. The circuit therefore passes from the battery through carbon E,
loose intermediate carbon G and carbon F; and thence to line, and so to a
receiving telephone at a distant station.
The object of the auger point B, is to allow of the tube A to be more conveniently
inserted into the ground, as shown in Figure 2.
Sound vibrations traversing the adjacent earth are communicated to the tube A
and so to the microphone electrodes E, G, F. The said electrodes are thereby
influenced to modify the battery current passing through them, so that the sounds
causing the aforesaid vibrations are reproduced in the receiving telephone connected
to line and may be noted and recognized by a listener.
In using the apparatus, it is proposed to place a number of the instruments
along a picket line, for example, wires leading from these instruments are then
conducted to any central point, as the head quarters of the commanding officer, and
all may be connected to a single receiving telephone at which a listener may be
constantly stationed. When suspicious sounds are heard in this receiver, the
listener, by breaking the circuits of the several instruments successively, for which
purpose suitable keys can be easily arranged, can locate in a few moments the
position of the source of the sounds. Timely warning is thus given of the direction
from which an advance of the enemy, for example is being made.
In Figure 3, the microphonic detectors are shown placed at various points H
along a road, and each detector communicates with a separate receiver I within a
fort. This arrangement may be employed for various purposes, such for example,
as to determine whether a sentry is on the alert and is pacing his beat.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :—
In combination with an implement adapted to penetrate solid substances, and
contained within the same, microphonic electrodes, and circuit connections, substan-
tially as described.
1
ca
1
1000