AN APPARATUS FOR INDICATING THE PRESSURE OF ELECTRIC CONDUCTORS IN FOREIGN BODIES
Year: 1862

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in
the County of Middlesex, and of 166, Buchanan Street, in the City of
Glasgow, North Britain, Gentleman, for the Invention of "AN APPARATUS
FOR INDICATING THE PRESSURE OF ELECTRIC CONDUCTORS IN FOREIGN BODIES."
-A communication from abroad. by Edmond Langlois, of Paris,. in the
Empire of France, Civil Engineer.
Sealed the 19th May 1863, and dated the 28th November 1862.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 28th November 1862.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of 166, Buchanan Street, in the City of Glasgow, North
Britain, Gentleman, do hereby declare the nature of the said Invention of
"AN APPARATUS FOR INDICATING THE PRESSURE OF ELECTRIC CONDUCTORS IN
FOREIGN BODIES," a communication from abroad by Edmond Langlois, of
Paris, in the Empire of France, Civil Engineer, to be as follows:-
This Invention relates to a peculiar construction and arrangement of appa-
ratus for discovering and indicating the presence of metallic bodies or other
conductors of electricity when these bodies are scattered, hidden, or dis-
seminated in other bodies non-metallic or non-conductive of électricity.

page_text: This peculiar apparatus consists essentially of a hollow sounding or testing
rod, within which is placed so as to be free to move to and fro another rod,
which in all cases is insulated completely from the outer tube or sounding rod.
One pole of a battery is connected with the outer tube, and the other pole
with the inner rod, and with either of these parts there is also connected so
as to be in the electric circuit a small electric alarm bell or signal and
galvanometer. The internal rod may either remain fixed to the tube, so
that is lower extremity is always flush with the end of the tube, or it may
when not in action be retained and held up away from the lower end of the
tube by means of a spring catch or other convenient contrivance. If this
apparatus be now inserted into a boring pushed into sand or submerged, the
instant the extremity of the tube comes in contact with or strikes a resisting
body, the resistance occasioned will effect the release of the inner rod and
cause it to descend until its extremity also comes in contact with the same
body; and if such body be metallic or conductive of electricity, a circuit will
be instantly established between the tube and the inner rod through the
contact therewith of the conductive medium, and a current of electricity will
pass through the apparatus, ringing the bell, and indicating its pressure on the
galvanometer. The extremity of the tube must, of course, be specially
adapted to the various uses to which it is to be applied, as for example, the
finding of the positions of gas and water mains or pipes, the discovery of
native minerals, gold, silver, and others; ores conductive of electricity, ores
containing metals disseminated therein, such as lead ores containing silver;
the finding of chain cables, anchors, and metallic portions of sunken wrecks.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Henry Johnson in the Great Seal Patent Office on
the 28th May 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex, and
of 166, Buchanan Street, in the City of Glasgow, North Britain, Gentleman,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of November, in the year of our
Lord One thousand eight hundred and sixty-two, in the twenty-sixth year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Henry Johnson, Her special license, that I, the said John

page_text: Henry Johnson, my executors, administrators, and assigns, or such others
as I, the said John Henry Johnson, my executors, administrators, or
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 Inven-
tion for "AN APPARATUS FOR INDICATING THE PRESSURE OF ELECTRIC CONDUCTORS
IN FOREIGN BODIES," a communication from abroad by Edmond Langlois, of
Paris, in the Empire of France, Civil Engineer, upon the condition (amongst
others) that I, the said John Henry Johnson, my executors or administrators,
by an instrument in writing under my hand and seal, or under the hand-
and seal of one of them, 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.
1
NOW KNOW YE, that I, the said John Henry Johnson, 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, reference being had to the accompanying Drawings
and to the letters and figures marked thereon, that is to say:-
The said Invention relates to a peculiar construction and arrangement of
apparatus for discovering and .indicating the presence of metallic bodies or
other conductors of electricity when these bodies are scattered, hidden, or
disseminated in other bodies non-metallic or non-conductive of electricity.
This peculiar apparatus consists, essentially of a hollow sounding or testing
rod, within which is placed so as to be free to move to and fro another rod.
which in all cases is insulated completely from the outer tube or sounding rod,
One pole of a battery is connected with the outer tube, and the other pole
with the inner rod, and with either of these parts there is also connected so
as to be in the electric circuit, a small electric alarm bell or signal and' gal-
vanometer. The internal rod may either remain fixed to the tube so that its
lower extremity is always flush with the end of the tube, or it may when not
in action be retained and beld up away from the lower end of the tube by
means of a spring catch or other convenient contrivance. If this apparatus
be now inserted into a boring; pushed into sand, or submerged, the instant the
extremity of the tube comes in contact with or strikes a resisting body, the
resistance occasioned will effect the release of the inner rod and cause it to
descend until its extremity also comes in contact with the same body; and if-

page_text: such body be metallic or conductive of electricity a circuit will be instantly
established between the tube and the inner rod through the contact therewith
of the conductive medium, and a current of electricity will pass through the
apparatus ringing the bell and indicating its presence on the galvanometer.
The extremity of the apparatus must, of course, be specially adapted to the
various uses to which it is to be applied, as far example, the finding of pro
jectiles in wounds, ascertaining the positions of gas and water mains or pipes;
the discovery of native minerals, gold, silver, and others; ores conductive of
electricity, ores containing metals disseminated therein such as lead ores con-
taining silver; the finding of chain cables, anchors, and submerged metallic
substances generally.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the Sheet of Drawings hereunto annexed..
Figure 1 represents an arrangement of apparatus adapted to the finding
and extraction of projectiles or metallic substances in and from wounds, and
also to the discovery of metallic or other articles conductive of electricity when
submerged or under water. This instrument is provided with hinged arms,
and operates by forced contact. The pressure upon or contact with the substance
is produced by the partial withdrawal of the internal rod, which is terminated
by a sphere acting as a wedge. The opening of the arms is effected by the
partial withdrawal of the internal tube, and the general manoeuvring of the
instrument is effected through the external tube. Figure 2 represents another
modification of the same apparatus, and principally applicable as a surgical
instrument for the discovery of projectiles or metallic bodies in gun-shot and
other wounds. In this arrangement the arms are insulated. In using the
apparatus a rod or arm is first introduced into the wound, and so soon as the
alarm indicates the presence of a metallic substance a second rod or arm is
introduced, and on due notice by the alarm being given that it has come in
contact with the metallic substance a third rod or arm is inserted, and so on,
until the metallic substance is surrounded or laid hold of on all sides. A
sliding ring is then pushed down the rods, so as to cause them to grip firmly
the metallic substance, which may then be withdrawn. Figure 3 represents
another form of apparatus applicable to the discovery of metallic substances in
wounds, submerged metallic substances, and metallic substances in the boreings
connected with mining. In this modification the wires connected with the
opposite poles of a battery, and colored in the Drawing red and black respec-
tively, are connected together by woven fabric, and then rolled into a spiral or
coil round an axis. The whole produces a cylinder, which is brought in

page_text: contact at its base with the substance sought to be discovered. Figure 4 is a
modified form of this apparatus composed of a series or group of external
wires, arranged round an internal non-conducting core of any suitable form or
material. The several wires are in two groups connected respectively with
opposite poles, and are severally arranged parallel to each other, but alter-
nating round the central core, as shown by the red and black lines in the
Drawing. All those wires communicating with one pole are connected
together, and kept insulated from those communicating with the opposite
pole, which are also connected together, as shown in the Drawing, the red
being shown in communication with the negative, and the black wires with
the positive pole of the battery. The several wires may be indented at
intervals into the central core, so as to leave annular grooves, in which lapping
may be laid to bind the wires to the core, but such lapping or binding must
not project beyond the general surface of the cylinder. This apparatus, as
well as that illustrated at Figure 5, may be employed for the discovery of
metallic substances in wounds, boreings, and metallic substances, or particles
in shifting or quick sand, and acts from the base as well as from its surfaces
or sides. Figure 5 represents in transverse and vertical section another.
arrangement of apparatus composed of a number of radial plates in combi-
nation with a bundle or group of wires in the centre of the core. One series
of poles are connected with an internal tube, whilst the other series unite in
a small metallic ring. It operates also from the entire surface, the wires in
Figure 4 being simply replaced by the metal plates. In cases where the non-
conducting or insulating core is required of considerable thickness it may be
made up of a bundle of small wires insulated from each other, and operating in
a similar manner to those of Figures 3 and 4. Figure 6 represents a palette-
shaped instrument provided with a curved contact surface. The metal com-
posing the body of the instrument serves as the conductor for one of the
poles of the battery and the wire which is inlaid therein (colored red in the
Drawing), communicates with the opposite pole. This wire should be made
to describe a number of curves, so as to multiply the contact surfaces. This
arrangement of apparatus will be found advantageous in making researches in
quick sands. Figure 7 represents an apparatus of a tubular construction, and
having an internal rod enclosed therein, and entirely sheathed or covered
thereby. One of the poles is connected with a tube in the interior of which
is fitted a rigid rod, which is in communication with the opposite pole of the
battery. The lower extremities of the tube and rod are not on the same level,
the tube extending slightly beyond the rod, so that when the tube comes in
contact with a solid body, by depressing slightly the rod it will also be brought

page_text: in contact with the body, and if it be metallic or conductive of electricity a
circuit will be established, and the bell or galvanometer will be acted upon.
On withdrawing the apparatus from the substance upon which both parts of
the instrument were pressed they will resume their original relative positions,
as the internal rod will be slightly elevated by a spring or otherwise. In
Figure 8 where the inner rod protudes beyond the tube it will regain its
position by its own gravity if made sufficiently heavy, if not, springs may be
used to draw it down, as shown. The instrument 7 (which is, by preference,
employed in the discovery of projectiles or other metallic bodies in wounds), is
manipulated by the collar a, and when the tube comes in contact with the
substance by continuing the pressure slightly the spring 6 will stretch, and the
internal rod will be drawn down until it also comes in contact with the same
substance. Figures 8, 9, and 10 represent respectively an instrument wherein
the inner rod projects beyond the outer tube; another having crossed or
cruciform palettes, and a third having a conical hollow sheath. In the last-
mentioned modification the internal and external conical surfaces are lined
or covered with a conducting wire inlaid in a spiral form. Figures 11 and 12
represent instruments having single palettes; Figure 13 represents the appli-
cation of curved hinged palettes. A spring or their own weight tends to keep
them close together; Figure 14 represents a screw or helicoidal form of
apparatus; all of which latter modifications are more particularly applicable to
the discovery of metallic substances or minerals in quick sands or under water.
The various kinds of apparatus may be constructed with several branches
túrning centres or hinges, and tending towards each other by the action of a
spring, so as to obtain a better and more perfect contact with the substance to
be discovered! In some cases a more intimate contact may be obtained by
exerting a mechanical pressure upon the movable or hinged parts either by
the aid of a screw, wedges, or a ring sliding over inclines on the parts to be
pressed together, or by any other suitable and well known mechanical con-
trivance for producing pressure. In some cases it will be found advantageous
to employ flexible apparatus, and then the conducting wires may be disposed
in a spiral form, or replaced by thin flexible blades inlaid or enclosed in rods,
which are also made flexible. When the apparatus is composed of several
branches a separate bell will be connected with each branch, in order to
indicate how many and which of the branches are in contact with the metallic
substance sought for. In all cases the wires must be insulated from each
other, and when the body of the instrument serves as the conductor the wire
will be inlaid therein, the grooves or channels formed to receive them being
first lined with any good non-conducting cement, and after the wires are

page_text: inserted the entire surface is to be made even by filing or otherwise, the
appearance being that illustrated at Figure 15 of the Drawings, where the red
color indicates the wires in cross section, and the black represents the non-
conducting cement.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is,
1st, the general construction and arrangement of apparatus for indicating the
presence of electric conductors in foreign bodies, as herein-before described.
2nd, the system or mode of discovering the presence of metallic substances
or electric conductors in foreign bodies by the application and use of an
electric sounding or testing apparatus, which will establish an electric circuit
on coming in contact with the substance sought for, substantially as herein-
before described.
3rd, the application and use of the instruments, herein-before described, to
and in the discovery of metallic substances, or substances conductive of elec-
tricity disseminated or lodged and hidden in other bodies or masses non-
conductive of electricity.
In witness whereof, I, the said John Henry Johnson, have hereunto
set my hand and seal, this Twenty-eighth day of May, One thousand
eight hundred and sixty-three.
J. HENRY JOHNSON. (L.S.)