Im- PROVEMENTS IN THE APPLICATIONS OF ELECTRICITY FOR THE TESTING AND DISCHARGE OF TORPEDO MINES, EITHER ON LAND OR AT SEA, AND IN THE APPARATUS CONNECTED THERE WITH
Year: 1865

page_text: LETTERS PATENT to Nathaniel John Holmes, of Number Nine, Primrose
Hill Road, London, Middlesex, Gentleman, for the Invention of "Im-
PROVEMENTS IN THE APPLICATIONS OF ELECTRICITY FOR THE TESTING AND
DISCHARGE OF TORPEDO MINES, EITHER ON LAND OR AT SEA, AND IN THE
APPARATUS CONNECTED THERE WITH."-Partly a communication from abroad
by Matthew Fontaine Maury, Office of the Imperial Administration of
the Admiralty, City of Mexico.
PROVISIONAL SPECIFICATION left by the said Nathaniel John Holmes,
at the Office of the Commissioners of Patents, with his Petition, on
the 8th December 1865.
I, NATHANIEL JOHN HOLMES, of Number Nine, Primrose Hill Road, London,
Middlesex, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE APPLICATIONS OF ELECTRICITY FOR THE TESTING AND
DISCHARGE OF TORPEDO MINES, EITHER ON LAND OR AT SEA, AND IN THE APPARATUS:
CONNECTED THEREWITH," to be as follows:-
First, the
power of daily testing the effective condition of the torpedo, and
the various connections, without risk or danger of explosion. The arrange

page_text: ments necessary to enable this essential function to be safely performed must
be in connection with the fusee placed within the charge of the mine, and
must also afford a passage to the discharging spark, as well as the testing
current. The arrangement has therefore a double duty to perform. The
manner in which this is carried out is as follows:-The conducting wires
being attached to the fuse, a metallic circuit is formed between them by means
of a short length of platinum wire properly insulated; by this means the
fuse is cut out of the circuit when tension currents of electricity are passed
through the conductors into the torpedo, and the effective condition of the
circuits can be accurately determined without the slightest risk of explosion,
the platinum wire connection offering little or no resistance to the passage of
"tension" currents of electricity.
Second, the power of speaking and telegraphing through the torpedo mines
without danger. The apparatus or telegraph employed is that worked by
"tension" currents, sufficiently powerful to explode the mine were the
platinum or other short circuit conductor removed from the fuse, and therefore
the test of passing this tension current through the metallic circuits and the
torpedo charge, either for testing or speaking purposes, is a satisfactory
acknowledgement that the circuits are complete. It cannot be mistaken for
earth currents, such as are induced in insulated metallic conductors, and
which not unfrequently render the test by voltaic currents unsatisfactory.
The apparatus employed both for the testing and speaking purposes is that
known as the magneto telegraph. In the magneto test nothing but the
original current sent out from the magneto instrument at one end of the con-
ductor can work the instrument at the other end of the conductor, and if this
current reaches the other end it must have passed through the torpedo or
series of torpedoes in circuit. This power of really passing a spark and tension
charge of electricity through the very charge of the torpedo without risk or
danger, is one of the important improvements made in the application of
electricity to the discharge of torpedoes.
Third, the power of exploding the torpedo or torpedoes at will. The nature
of the current employed to ignite the fusee is distinct from that employed
to test the fusee. The effects to be produced therefore by the first or testing
current must be harmless and quite distinct from the results obtained by the
second or igniting current when both are successively passed into the same
circuit. Neither shall it be possible in any way for the one current to perform
the effects intended to be developed by the other current, that is to say, the
testing or tension current shall not be able to explode the mine, and in the
same way the firing or accumulated current cannot possibly be employed for

page_text: testing. This distinction between the employment of "tension" currents and
"accumulated" currents, and the necessary arrangement of parts to secure
the certainty of the action of the testing or tension current, and of the firing
For accumulated current in the management and discharge of the torpedo is
5 of the utmost importance, as it at once gives the entire control over the system,
and avoids all possibility of danger from accidental discharges. This arrangé-
ment is a new and valuable practical application of electricity to the discharge
of torpedoes. It depends upon the difference of action or result when a
"tension" or an "accumulated" current is passed into the circuit and fusee
0 arrangement. The fine platinum wire, while it admits freely the
passage of
⚫the tension current, obstructs the passage of the accumulated current, which has
therefore no choice but to pass through the fusee, igniting it and exploding
-the mine. In the manipulation of the fusee for igniting the mine it is essential
that the several parts connected with the discharge should be all thoroughly
5 insulated from the charge.
Fourth, that the explosion of the torpedo or mine shall only take place
when the vessel shall be within the area of its destruction, and that it
.shall not be possible to fire the mine, except under the above conditions.
For this purpose the electrical circuits in connection with the discharge of
the torpedo must be arranged so as to complete or break the circuit for the
transmission of the accumulated charge at the precise moment that the vessel
either enters or leaves the radius of destruction of the sunken or buried
torpedo. These arrangements embrace a plan for determining by cross bearings
when the enemy is in the torpedo field of destruction, and for "making con-
5 nections amongst the torpedo wires in a certain way, and by which (the
.concurrence of two operators becomes necessary for the explosion of any
one or more torpedoes. This plan requires each operator to be so placed or
stationed that a line drawn straight from them to the place of the torpedoes may
intersect as nearly as practicable at right angles, and it requires the connec-
tions to be such that each operator may put his station in or out of circuit
at will. When the torpedoes are laid a range from each station is established
for every torpedo or group of torpedoes. When either operator observés
an enemy in' range with any torpedo, he closes his circuit for that torpedo.
.If the enemy, before getting out of this range, should enter the range for
any torpedo from the other station, the operator then closes his circuit and
discharges the accumulated.current, Consequently, if the range belongs
to the same toŕjedo, its' explosion takes place, but if not there. will bé. no
explosion, hence, here is an artifice by which explosion becomes impos-
sible when the enemy is not within the field of destruction, and sure when

page_text: he is. At the same time the position of the sunken torpedoes remain
undiscovered to the enemy, no buoy or other mark being required to indicate
its place.
The arrangement of the conductors and necessary concurrence
of two or more observers to close the circuits at the precise moment a
vessel is at the intersection of the range of any torpedo also ensure their
non-explosion to friendly vessels, and the torpedo becomes no obstruction to
.navigation.
Fifth, a plan for planting torpedoes where the water is too deep for them
to lie on the bottom and explode with effect, by which they will not interfere
with the navigation of the channel, and by which when the enemy makes his
.appearance they may by the touch of a key be brought instantly into the
required position, and at the proper depth. The arrangement by which this
is effected is as follows:-The torpedo is regulated to float at the proper
depth by suitable attachments to keep it in position when it is free to exert
its buoyant tendancy. A hollow water-tight cast-iron shell is firmly moored
at a suitable distance from the torpedo, and able to withstand any strain
exerted upon it by reason of the buoyancy of the torpedo. The torpedo is
securely attached to this shell by a rope, which effectually keeps it tied down.
In the interior of the shell is a fuse and small charge of gunpowder, sufficient
to explode the shell and liberate the rope holding down the torpedo, which
then floats up to its normal position ready for ignition. A conducting wire
passes from the fusee in the shell to the testing and firing station, and
-through which a current can be transmitted to ignite the charge and destroy
.the shell.
Sixth, a plan for planting the torpedoes when the current is strong, so that
they may be always held in position at the required depth. In this arrange-
*ment the velocity of the stream is made use of as a motive power for raising
the torpedo by causing the water to impinge upon an inclined plane fixed to
-the sides of the torpedo, and reversing itself with the set of the current. The
action of the water upon this inclined plane being similar to that of the wind
in raising a kite, the upward or rising tendency which is thus exerted upon
the torpedo will be in direct antagonism to the sweeping action in the
.direction of the current. When the torpedo is buoyed in channels with
strong tideways the form of the floating tank should be that of an ellipse.
The torpedo will therefore always keep head to the stream, and so avoid any
tendency to rotate upon its centre of equilibrium.
Seventh, the torpedo tank or case being generally metallic and in direct
contact with the earth, either by immersion in the water or concealment in
the ground, the circuits and fusee arrangements within the torpedo connected

page_text: with the "testing," speaking," and "ignition" of the mine require to be
properly insulated from the torpedo case and charge, an essential part of my
improved applications of electricity to the discharging of torpedoes and mines,
either on land or at sea. It is by the new combinations here described that
I have reduced the torpedo to a system, and established that the various
material to build up the mine can all be constructed upon an ascertained
and well-defined principle. These various parts are the "conductor," the
"speaking" and "testing" apparatus, the "igniting" apparatus, the "test
cartridges," containing the fuse and platinum wire arrangements, and the
torpedo cases.
Eighth, by a proper arrangement of the metallic circuits at the firing and
speaking stations, it is also a part of my system to prevent the exploding of the
torpedo by the enemy, should he succeed in getting hold of the metallic con-
ductor. This I carry into effect by always having the circuits at the firing and
speaking stations "broken" or "open" circuits, so that no circuit can be formed
by the enemy to pass a spark, even do he connect the wire he has discovered
with any suitable discharging apparatus. These circuits are only closed when
it is intended to explode the mine in connection with the range of the torpedo.
By means of the fusee arrangements I have above described, I am able likewise
to effectively discharge with the accumulated current several torpedoes simul-
taneously with a single conductor, without having recourse to divided circuits.
This is likewise a new and important part of my improvements in the appli-
cation of electricity to the discharge of mines.
It understood that I do not confine myself to any particular form of
apparatus or parts in the carrying out of these my new combinations as applied
to the use and ignition of torpedo mines for defence against the approach of
an enemy where electricity is employed. The novelty of my Invention consists
in the combinations employed to bring about the testing and speaking through
the mines by the employment of a "tension" current, and the ignition of the
mines by an "accumulated" current, and the other arrangements of parts and
conductors to ensure the ignition of the mine only when the enemy shall be
within its area of destruction, together with the other various essential
elements of detail in the construction, submerging, and carrying out of the
system as a whole, and the complete system of defence herein described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters, Patent, filed
by the said Nathaniel John Holmes in the Great Seal, Patent Office on
the 8th June 1866,
TO ALL TO WHOM THESE PRESENTS.SHALL COME, I, NATHANIEL
JOHN HOLMES, of Number Nine, Primrose Hill Road, London, Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters'
Patent, bearing date the Eighth day of December, in the year of our Lord One.
thousand eight hundred and sixty-five, in the twenty-ninth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Nathaniel John Holmes, Her special licence that I, the said Nathaniel John
Holmes, my executors, administrators, and assigns, or such others as I, the said;
Nathaniel John Holmes, 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, 1
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 APPLICATIONS OF ELECTRICITY FOR, THE TESTING AND DISCHARGE OF TORPEDO
MINES, EITHER ON LAND OR AT SEA, AND IN THE APPARATUS CONNECTED THEREWITH,"
partly communicated to me from abroad by Matthew Fontaine Maury, Office of a
the Imperial Administration of the Admiralty, City of Mexico, and is partly
of my own Invention, upon the condition (amongst others) that I, the, said,
Nathaniel John Holmes, 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 Nathaniel John Holmes, of 9, Primrose:
Hill Road, London, do hereby declare the nature of my said Invention, and:
in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :—
First, the power of daily testing the effective condition of the torpedo and:
the various land or submarine connections without risk or danger of explosion.
The arrangements necessary to enable this essential function to be safely per-
formed must be in connection with the fuse or igniter placed within the charge
of the mine, and the combination of parts must also afford a passage to the
discharging spark through the fuse, as well as the testing current through the

page_text: torpedo connections and circuits.
The arrangement has therefore a double
duty to perform, and the manner in which this is carried out is as follows:-
The conducting wires being attached to the fuse a metallic circuit is formed'
between them within the torpedo case, by means of a short length of fine
platinum or other suitable wire properly insulated, and called the bridge, the
required length of this bridge being adjusted by experiment to the resistance'
of the circuits, fuses, and mines to be ignited. By this means the fuse within
igniter or charge is cut out of the circuit, when intensity currents of electricity
are passed from station to station through the conducting wire and into the
charge of the torpedo, thus enabling the effective condition of the circuit
wires to be at all times accurately determined without the slightest risk of
explosion, the fine platinum wire or bridge connection between the two'
conducting wires entering the fuse offering little or no resistance to thoi
passage of intensity currents of electricity, the metallic circuit by this
arrangement being intact and unbroken throughout the entire length of the
electrical. connections: In this arrangement of the metallic bridge the'
igniting fuse is intermediate between the two extremities of the bridge, and,*
as it were, cut out of the circuit, the metallic bridge offering a much more
ready path to the passage of intensity currents than the resistance and non-'
metallic circuit of the fuse. In order, however, to ensure that the bridge shall'
be the only path for the passage of the intensity or the testing current, and'
to avoid all possibility of 'accidental ignition of the mine, à gulf, or broken'
circuit may be interposed between the fuse and the bridge connection, so that
the passage of the intensity or the testing current is not only impeded by the
fuse resistance, but absolutely interrupted by the mechanical break or gulf in
the conducting wire joining the fuse to the bridge. While, therefore, this
metallic break and fuse resistance absolutely prevents the passage of the
testing current through the fuse, and forces it to select the metallic continuity
of circuit offered by the bridge, it will be understood that the passage of the
igniting or accumulated current is not impeded, the gulf and fuse-offering no
impediment to its passage through the fuse for the discharge of the mine,
while the bridge connection on the contrary is impassable, and may be con-
sidered to represent an almost infinite resistance to the igniting current'or
spark, which is thus forced through the fuse and gulf.
Second, the power of speaking and telegraphing through the torpedo mines
without danger. For this purpose any apparatus or telegraphs may, be
employed that are worked by tension or intensity currents. It is, however, to
be preferred that the currents produced by these machines should be sufficiently'
powerful: to explode the mine were the platinum bridge or short circuit

page_text: conductor removed from the fuse. It will therefore be clear that the test of
passing these tension or intensity currents through the metallic circuits,
conductors, and the torpedo charge, either for testing or speaking purposes,
will be a satisfactory acknowledgement that the circuits and internal torpedo
arrangements are complete. These currents cannot be mistaken for earth
currents, such as are induced in insulated metallic conductors, and which not
unfrequently render the test by weak voltaic currents unsatisfactory. One
form of the apparatus employed both for the speaking and testing purposes
is that known as Wheatstone's magneto telegraph. In instruments of this
class nothing but the original current sent out from the magneto instrument
at one end of the conductor can reciprocally work the instrument at the other
end of the conductor, and if this current reaches the other end, it must have
passed through the torpedo or series of torpedoes intermediate in circuit. This
power of really practically passing an intensity current of electricity through
the internal charge and connections of the torpedo mine without risk or
danger of explosion is one of the important improvements made in the
application of electricity to the discharge of torpedoes.
.
Third, the power of exploding the topedo or torpedoes at will. The nature
of the current employed to ignite the fuse is distinct from that employed to
test the fuse. The effects to be produced therefore by the first or testing
current must be harmless as regards the ignition of the mine, and quite
distinct from the results obtained by the second or igniting current, when
both are successively passed into the same circuit; neither shall it be possible
in any way for the one current to perform the effects intended to be developed
by the other current, that is to say, the testing or intensity current shall not
be able to explode the mine; and in the same way the firing or accumulated
current cannot possibly be employed for testing. This distinction between
the employment of intensity currents and accumulated currents, and the
necessary arrangement of parts in connection with the bridge and the gulf,
either singly or combined, to secure the certainty of the action of the testing
or intensity current and of the firing or accumulated current in the manage-
ment and discharge of the torpedo is of the utmost importance, as it at once
gives the operator entire control over the system, and avoids all possibility of
danger from accidental discharges. This arrangement and use of intensity
and accumulated currents of electricity is new, and forms a very valuable
practical application of electricity to the discharge and effective employment
of the torpedo. It depends upon the difference of action or result when an
intensity or an accumulated current is passed into the circuit and fuse
arrangement. The fine platinum wire bridge, while it admits freely the

page_text: passage of the intensity current, obstructs the passage of the accumulated
current, which has therefore no choice but to pass through the fuse and gulf,
igniting it and exploding the mine. In the manipulation of the fuse
arrangements for igniting and testing the mine it is essential that the several
parts connected with the ignitor or discharger should be all thoroughly
insulated from the charge and the torpedo case.
Fourth, that the explosion of the torpedo or mine shall only take place
when the vessel shall be within the area of its destruction, and that it shall
not be possible to fire the mine except under the above conditions. For
this purpose the electrical circuits in connection with the igniter of the
torpedo must be arranged so as to complete or break the circuit for the trans-
mission of the accumulated charge at the precise moment that the enemy
either enters or leaves the area of destruction of the sunken or buried mine.
These arrangements embrace a plan for determining by cross bearings when
the enemy is in the torpedo field of destruction, and for making connections
amongst the torpedo wires in a certain way, and by which the concurrent
observation of two operators becomes necessary for the explosion of any one
or more torpedoes. This plan requires each operator to be so placed or
stationed that a line drawn straight from them to the place of the torpedoes
may intersect as nearly as practicable at right angles, and it requires the
connections to be such that each operator may put his station in or out of
circuit at will. When the torpedoes are laid a range from each station is
established by means of suitable observing instruments for every torpedo or
group of torpedoes. When either operator observes an enemy in range with
any torpedo he closes his circuit for that torpedo. If the enemy before
getting out of this range should enter the range for any torpedo from the
other station that operator also closes his circuit, and discharges the accumu-
lated current into the wires; consequently, should the ranges be concurrent
with one and the same torpedo or group of torpedoes, the explosion of the
mine must take place, but if not there will be no explosion; hence, here is
an artifice by which explosion becomes impossible when the enemy is not
within the field of destruction, and sure when the enemy is ; at the same time
the position of the sunken torpedoes remain undiscovered to the enemy, no
buoy or other mark being required to indicate their place. By this arrange-
ment of the conductors and necessary concurrence of two or more observers to
close the circuits at the precise moment the enemy is at the intersection of the
range of any torpedo, their non-explosion to friendly vessels is secured, and
the torpedo itself becomes no obstruction to navigation.
Fifth, a plan for planting torpedoes where the water is too deep for them.

page_text: to lie on the bottom and explode with effect, by which they will not interfere
with the navigation of the channel, and by which when the enemy makes
his appearance they may by the touch of a key be brought instantly into the
required position, and at the proper depth. The arrangement by which
this is effected is as follows:-The torpedo is regulated to float at the proper
depth by suitable attachments to keep it in position when it is free to exert
its buoyant tendency, a hollow water-tight iron shell, or other suitable
receptacle for a bursting charge of powder is firmly moored at a suitable
distance from the torpedo, and able to withstand any strain exerted upon it
by reason of the buoyancy of the torpedo. The torpedo is securely attached
to this shell or case by a rope which effectually keeps it tied down. In the
interior of the shell or case is a fuse for the ignition of the charge of gun-
powder, and which on explosion will burst the shell and liberate the rope
holding down the torpedo, which then floats up to its normal position ready
for ignition. A conducting wire passes from the fuse in the shell or case to
the testing and firing station, and through which a current can be transmitted
to ignite the charge and destroy the shell.
Sixth, a plan for planting the torpedoes when the current is strong, so that
they may be always held in position at the required depth. In this arrange-
ment the velocity of the stream is made use of as a motive power for raising
the torpedo by causing the water to impinge upon an inclined plane fixed to
the sides of the torpedo, and swinging or reversing itself with the set of
the current. The action of the water upon this inclined plane being similar
to that of the wind in raising a kite, the upward or rising tendency which
is thus exerted upon the torpedo will be in direct antagonism to the sweeping
action in the direction of the current. When the torpedo is buoyed in channels
with strong tide ways, the form of the floating tank may be that of an ellipse,
the torpedo case thus shaped will always keep head to the stream, and so
avoid any tendency to rotate upon its centre of equilibrium.
Seventh, the torpedo tank or case being generally metallic and in direct
contact with the earth either by immersion in the water or concealment in
the ground, the circuits and fuse arrangements within the torpedo connected
with the testing, speaking, and ignition of the mine require, to ensure the
integrity of the testing and firing currents, to be properly insulated from the
torpedo case and charge, and this feature is an essential part of my improve-
ments in the application of electricity to the testing, speaking through, and
discharging of torpedoes and mines either on land or at sea. It is by the
new combination of parts here described that I have reduced the torpedo to
a system, and established that the various material and parts required to build

page_text: up the mine can all be constructed and combined upon an ascertained and
well-defined principle. These various parts consist of the conducting wires,
the speaking and testing apparatus, the igniting apparatus, the igniter cart-
ridges containing the 'fuse, bridge, and gulf arrangements, and the torpedo
cases. It is understood that various forms of apparatus may be employed to
produce both the intensity or testing current and the accumulated or firing
current. It is not necessary for the purposes of these combinations of parts
to confine myself in these respects to any particular form of apparatus, the
effect produced being the result of passing the currents so generated into
certain arrangements of circuits, conductors, and parts, and is not consequent
upon the mode of the production of the currents themselves.
Eighth, by a proper arrangement of the metallic circuits at the firing ‘and
speaking stations it is also part of my system to prevent the explosion of the
torpedo by the enemy, should he succeed in getting hold of one end of the
metallic conductor. This I carry into effect by employing for the return
circuit a metallic wire in place of using the natural earth, and always keeping
the circuits at the firing and speaking stations broken or open circuits, so
that no circuit can be formed by the enemy to pass a spark through the minė,
even is the wire he has discovered connected with any suitable discharging
apparatus. These circuits can only be closed by the operator at his range,
when it is intended to explode the mine in connection with the concurrence of
observation at another station. By means of the fuse arrangements I have
above described I am able likewise to effectively test, telegraph through, and
discharge with the intensity and accumulated current respectively, several
torpedoes simultaneously with a single conductor, without having recourse to
divided circuits. This is likewise a new and important part of my improve-
ments in the application of electricity to the discharge of mines.
In order to give notice at the observing stations that the enemy has
successfully employed means for breaking the conducting wires, currents of
intensity electricity may be continuously passed through the wires in connec-
tion with alarm bells, contrived to ring only when the current is interrupted,
and so give notice of any successful attempt to destroy the circuits. When
such attempts are made by the enemy under cover of darkness, guns may be
discharged sighted permanently in range with each group of mines, to rake
the line and preserve the integrity of the conducting wires from interruption.
It is understood that I do not confine myself to any particular form of
apparatus or parts in the carrying out of these my new combinations as
applied to the use and ignition of torpedo mines, for defence against the
approach of an enemy when electricity is employed.

page_text: The novelty of my improvements consist in the combinations employed to
bring about the testing and speaking through the mines by the employment of
an intensity current, and the practically instantaneous ignition of the mines
with absolute security at the will of the operator, by substituting an accumu-
lated current, together with the other arrangements and combinations of
parts and conductors necessary to ensure the ignition of the mine only when
the enemy shall be within its area of destruction, as determined by the con-
current observation of two or more observers, together with the other various
essential elements of detail in the construction and use of the bridge, gulph,
torpedo, fans, mooring, submerging, and the carrying out of the system either
as a whole, or individual combinations necessary to establish the complete
system of torpedo defence herein described.
In witness whereof, I, the said Nathaniel John Holmes, have hereunto
set my hand and seal, this the Eighth day of June, in the year of
our Lord One thousand eight hundred and sixty-six.
Witness,
LEWIS C. HUTSLET,
Fitzroy Park,.
Highgate.
NATH. J. HOLMES. (L.B.)