AN ELECTRO-BALISTIC CHRONO- GRAPHE
Year: 1864

page_text: LETTERS PATENT to Paulus Æmilius Le Boulengé, of Brussels, in the
Kingdom of Belgium, Officer in the Artillery of His Majesty the King
of the Belgians, for the Invention of "AN ELECTRO-BALISTIC CHRONO-
GRAPHE."
Sealed the 17th January 1865, and dated the 23rd July 1864.
PROVISIONAL SPECIFICATION left by the said Paulus Æmilius Le
Boulenge at the Office of the Commissioners of Patents, with his
Petition, on the 23rd July 1864.
I, PAULUS EMILIUS LE BOULENGE, of Brussels, in the Kingdom of Belgium,
Officer in the Artillery of His Majesty the King of the Belgians, do hereby
declare the nature of the said Invention for "AN ELECTRO-BALISTIC CHRONO-
GRAPHE," to be as follows:-
This Invention consists in an electric chronographe for measuring short
spaces of time with great accuracy, and especially for denoting the time a'
projectile takes to pass through a portion of its trajection.
And in order that my improvements may be clearly understood, I give the
following description thereof, reference being had to the figures and letters on
the accompanying Sheet of Drawings, in which Figs. 1 and 2 are vertical
elevations of the apparatus complete; Fig. 3, a part of the apparatus detached;
Fig. 4, a view of the piles and circuits adopted; and Fig. 5, a view of a con-
troller for testing the working condition of the chronographe.

page_text: The measure of time is based on the law of gravity, and for the chrono-
meter or time measurer I employ a hollow metallic cylinder or tube a, having
at the top a steel plug in contact with an electro-magnet l. Two paper tubes
b, b', one of which is drawn about full size in Fig. 3, are placed with a slight
friction upon the cylinder a, one resting on the collar or support c', and the
other on the collar c of the bottom plug d, and it is on these paper tubes that
marks which serve to measure the time are cut by means of a knife f, put in
motion by the release of a catch lever or trigger g and parts connected with it
at the bottom of the wooden frame m, the trigger being liberated by the
falling of the weight i from the electro-magnet , to which it was suspended.
The disconnector shewn at j, k, and which will be hereafter more fully
described, is for the purpose of breaking the two currents of the electro-
magnets and exactly at the same instant of time. The chronometer and
the weight being suspended at their respective magnets, and the trigger being
cocked, if the finger be applied to the button and also to the disconnector, the
two circuits are broken at the same instant, and allow the chronometer and
weight to fall. The chronometer in its fall passes a short distance from the
knife f, and the weight i falls upon the table end of the catch lever or
trigger g, and raises at the other end the catch, so as to allow the spring e to
give movement to the knife, and enable it to cut a mark in the lower paper
tube b. The height of the mark from the bottom of the tube is then measured
and to that distance is added a length of 500 millimitres corresponding with
the distance between the cutting point of the knife and the line c, when the
chronometer is supported. There is thus obtained a height of fall which may
be called H, corresponding to a time T; this time therefore is that during
which the chronometer falls before registering, when the ruptures of the two
circuits are simultaneous. If instead of breaking the circuits simultaneously
they are broken by the action of a projectile traversing successively two object
frames (cadres cibles, in French), and thereby breaking first the circuit of the
electro-magnet l, and then after a portion of time t (say about a second) the
circuit of the electro-magnet ; the fall of the chronometer will precede that
of the weight, and the marks in this experiment will be marked upon the
upper paper tube 61. Thus there is obtained a second height H' of the fall
corresponding with a time T', and the difference between T and T¹ will give
exactly the measure of the time t which the projectile has taken to pass
through the space from one object frame to the other, and if this space be
called E, will be the speed of the projectile between the frames. In order
to obtain the simultaneous action of the two electric currents they are
combined in such manner that though they are individually separated and

page_text: without influence one upon the other, they may have nevertheless a common
action in their passage, and for this purpose it is sufficient to employ a dis-
connector which will act equally on both circuits. This disconnector operates
by breaking the contact which exists between the spring j and the screw k,
which form two parts of the common conductor. Fig. 4 represents the
arrangement of the piles and the circuits adopted. Two poles having an equal
number of elements of Bunsen have two of their poles of the same name, the
two carbon poles e and e¹ being joined together by metal fixings. The circuit
of the chronometer parting from the zinc pole a is connected to the first object
frame b, c, from whence it is returned to the bobbin of the electro-magnet of
the chronometer, and from thence to the carbon pole by the conductor d, e,
the circuit of the weight follows a similar course as at a, b, c, d, but from the
said carbon pole instead of finishing its circuit directly at d, e, this conductor
is replaced by another d', f¹, e, e¹, and then the part f, e, is common to the
two circuits, and it is that one which is broken by.the disconnector. Besides
the circuit just described there exists upon each of the electro-magnets a
second circuit derived from the same pile, but rolled up in a contrary direction
upon the bobbins. This circuit which I call inverse is neither broken by the
disconnector or by the projectile, it serves to reverse rapidly the poles of the
electro-magnet at the instant of the rupture of the direct circuit.. The
mountings of the electro-magnets are made of steel to prevent the poles from
changing, and thereby avoid the effects of attraction in the first instant of
the fall.
To this apparatus may also be applied the method of indication obtained by
the spark of induction. In this case the instrument in its constituent parts
only requires a chronometer in connection with an electro-magnet and a frame
holding two points, between which the sparks will fly when the projectile in
its passage causes the rupture of the indicating circuits.
The chronometer for this purpose is a flat steel plate containing a longi-
tudinal opening, over which is placed a piece of paper, and during the fall of
the chronometer the paper passes between the two points without touching
them, and thus receives the traces of the sparks.
The chronometer is held stationary by a current of electricity, and falls
when the current is broken either by the projectile or by the instrument which
fires the cannon or fire-arm. The experiment is conducted in such a manner
that the chronometer shall have acquired a certain swiftness of fall before the
projectile arrives at the first object frame, on which passes the inducting
circuit of a Rhumskorff bobbin, the said current finishes at the before-
mentioned points, and the rupture of the object frame breaks the current and

page_text: produces a spark which pierces the paper when the chronometer has fallen
the height H before described. A rupture of a second inducting circuit by
the same projectile gives the trace of a second spark corresponding with the
additional height H. The time of the passage of the projectile between the
two object frames will be given by the difference of the time T and T corre-
sponding respectively with the heights or elevations H and H.
The apparatus thus modified is applicable to the measure of velocity in the
barrel of a fire-arm, or the distance from the breech to the muzzle, in which
case and also others in which the distances are short, it is not necessary to
give a great developement to the indicating circuits.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Paulus Emilius Le Boulengé in the Great Seal Patent
Office on the 20th January 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PAULUS
ÆMILIUS LE BOULENGE, of Brussels, in the Kingdom of Belgium, Officer in
the Artillery of His Majesty the King of the Belgians, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of July, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Paulus Emilius Le Boulengé, Her special licence that I, the said Paulus
Emilius Le Boulengé, my executors, administrators, and assigns, or such
others as I, the said Paulus Æmilius Le Boulengé, my executors, adminis-
trators, and assigus, 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 "AN ELECTRO-BALISTIC CHRONOGRAPHE," upon the condition
(amongst others) that I, the said Paulus Æmilius Le Boulengé, 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.

page_text: NOW KNOW YE, that I, the said Paulus Æmilius Le Boulengé, 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 fol-
lowing statement (that is to. say):
This Invention consists. in an electric chronographe for measuring short
spaces of time with great accuracy, and especially for denoting the time. a
projectile takes to pass through a portion of its trajection.
And in order that my improvements may be clearly understood, I give the
following description thereof, reference being had to the figures and letters on
the accompanying Sheet of Drawings, in which Figs. 1 and 2 are vertical eleva-
tions of the apparatus complete; Fig. 3, a part of the apparatus detached ;
Fig. 4, a view of the piles and circuits adopted; and Fig. 5, a view of a
controller for testing the working condition of the chronographe.
The measure of time is based on the law of gravity, and for the chrono-
meter or time measurer I employ a hollow metallic cylinder or tube a having:
at the top a steel plug in contact with an electro-magnet l. Two paper
tubes 6, 6', one of which is drawn about full size in Fig. 3, are placed with a.
slight friction upon the cylinder a, one resting on the collar or support c', pro-
vided with a steel ring d', and the other on the collar c of the bottom plug d
and it is on these paper tubes that marks, which serve to measure the time,
are cut by means of a knife ƒ put in motion by the release of a catch lever or
trigger g, and parts connected with it at the bottom of the wooden frame m;:
the trigger being liberated by the falling of the weight i, which is made of
steel, from the electro-magnet 1 to which it was suspended. The disconnector
shewn at j, k, and which will be hereafter more fully described, is for the..
purpose of breaking the two currents of the electro-magnets 1 an 11 exactly at
the same instant of time, the chronometer and the weight being suspended
at their respective magnets, and the trigger being cocked; if the finger be
applied to the button, and also to the disconnector, the two circuits are broken
at the same instant, and allows the chronometer and weight to fall. The
chronometer in its fall passes a short distance from the knife. f, and the
weight i falls upon the table end of the catch lever or trigger g, and raises; at.:
the other end the catch, so as to allow, the spring e to give movement to
the knife, and enable it to cut a mark in the lower paper tube 6. The height::
of the mark from the bottom of the tube is then measured, and to that:
distance is added a length of 500 millimetres. corresponding with the distance>
between the cutting point of the knife, and the line, c. when: the chronometer is
supported. There is thus obtained a height of fall, which may be called H,,
corresponding to a time T. This time therefore is, that during which the

page_text: chronometer falls before registering, when the ruptures of the two circuits are
simultaneous. If instead of breaking the circuits simultaneously they are
broken by the action of a projectile traversing successively two object frames
(cadres çibles, in French), and thereby breaking first the circuit of the electro-
magnet l, and then after a portion of time t (say, about 0". 1) the circuit of
the electro-magnet 11, the fall of the chronometer will precede that of the
weight, and the marks in this experiment will be marked upon the upper
paper tube 6. Thus there is obtained a second height H¹ of the fall cor-
responding with a time T, and the difference between T and T¹ will give
exactly the measure of the time t, which the projectile has taken to pass
through the space from one object frame to the other, and if this space be
called E,, will be the speed of the projectile between the frames. In order
to obtain the simultaneous action of the two electric currents they are com-
bined in such manner that though they are individually separated and without
influence one upon the other, they may have nevertheless a common action in
their passage, and for this purpose it is sufficient to employ a disconnector,
which will act equally on both circuits. This disconnector operates by breaking
the contact which exists between the spring j and the screw k, which form two
parts of the common conductor. Fig. 4 represents the arrangement of the
piles and the circuits adopted. Two piles having an equal number of elements
of Bunsen have two of their poles of the same name, the two carbon poles e
and e¹ being joined together by metal fixings. The circuit of the chronometer
parting from the zinc pole a is connected to the first object frame b, c, from
whence it returns to the apparatus and passes to the bobbin d of the electro-
magnet of the chronometer, and from thence to the carbon pole e by the
conductor d, e; the circuit of the weight follows a similar course as at a³, b¹, c', d',
but from the said carbon pole instead of finishing its circuit directly at d¹, e',
this conductor is replaced by another d, f, e, e¹, and then the part f, e, is
common to the two circuits, and it is that one which is broken by the
disconnector.
Besides the circuit just described there exists upon each of the electro-
magnets a second circuit derived from the same pile, but rolled up in a
contrary direction upon the bobbins. This circuit, which I call inverse, is
neither broken by the disconnector nor by the projectile; it serves to reverse
rapidly the poles of the electro-magnet at the instant of the rupture of the
direct circuit. The inverse currents have, like the direct, a common part x, x¹,
in this is inserted a rhéostat, by means of which the resistance of the inverse
currents can be regulated. This rhéostat of simple construction is capable of
varying the resistance from 1 to 160 m., and may be fixed upon the frame-

page_text: work of the apparatus. The mountings of the electro-magnets are made of
steel to prevent the poles from changing, and thereby avoid the effects of
attraction in the first instant of the fall.
To this apparatus may also be applied the method of indication obtained by
the spark of induction. In this case the instrument in its constituent parts
only requires a chronometer in connection with an electro-magnet and a frame
holding two points, between which the sparks will fly when the projectile in
its passage causes the rupture of the indicating circuits. The chronometer
for this purpose is a flat steel plate containing a longitudinal opening, over
which is placed a piece of paper, and during the fall of the chronometer the
paper passes between the two points without touching them, and thus receives
the traces of the sparks. The chronometer is held stationary by a current of
electricity, and falls when the current is broken either by the projectile, or by
the instrument which fires the cannon or fire-arm. The experiment is con-
ducted in such a manner that the chronometer shall have acquired a certain
swiftness of fall before the projectile arrives at the first object frame, on which
passes the inducting circuit of a Rhumskorff bobbin, the said current finishes
at the before-mentioned points, and the rupture of the object frame breaks the
current and produces a spark, which pierces the paper when the chronometer
has fallen the height H before described. A rupture of a second inducting
circuit by the same projectile gives the trace of a second spark corresponding
with the additional height H. The time of the passage of the projectile
between the two object frames will be given by the difference of the time T¹
and T, corresponding respectively with the heights or elevations H¹ and H.
The apparatus thus modified is applicable to the measure of velocity in the
barrel of a fire-arm, or the distance from the breech to the muzzle, in which
case, and also others in which the distances are short, it is not necessary to
give a great development to the inducting circuits.
Having now described the nature and particulars of my said Invention, and
the manner in which the same is to be performed, I conclude with a list of the
letters on the Figures in the Drawings, and the names of the parts on which
they are marked.
Chronometer.
a, represents a hollow metallic tube or cylinder;
6 and 6', paper tubes;
c, c, and c¹, c', bearings for the paper tubes;
d, a screwed plug acting as ballast;

page_text: e, a strong spring ;
f, a knife;
7, a hooked lever or trigger;
h, a small spring;.
9, a stay or buttress.
, a steel weight;
, a screwed plug acting as ballast.
, represents a spring ;
c, a screw;
a, a disconnecting knob or button.
m, m, a frame of wood;
w, a slab or table of support;
o, the sole or foundation board of the apparatus, to which is
adjusted the table w;
o, screws fixed to the sole or foundation;
n, nuts for adjusting and fixing the, table;
z, fastening screws.
3, s, represent the direct circuits of the chronometer;
1, 81, the inverse circuits of do. ;
t, t, the direct circuit of the weight;
1,t, the inverse do.
do. ;
u, u', the copper conducting wires;
v, v, the common conductor of the direct currents;
x, x³, the common conductor of the inverse currents, in which
the rheostat is interposed;
and y, y', the conductor common to the direct and inverse
currents.
whereof, I, the said Paulus Æmilius Le Boulengé, have
set my hand and seal, this Thirteenth day of January, in
of our Lord One thousand eight hundred and sixty-five.
DATILLIS ÆMILIUS LE ROULENCÉ (10)
PAULUS MILIUS LE BOULENCÉ (10)