Improvements relating to Signalling by Sound.
Year: 1898

page_text: Improvements relating to Signalling by Sound.
I, EMMANUEL DRAGOUMIS, of 22, Rue de Marseille, Athens, in the Kingdom of
Greece, Gentleman, do hereby declare the nature of this invention to be as
follows:-
This invention consists of an apparatus intended to produce a series of sonorous
signals in such a manner as to allow a person who observes the same, to ascertain in
what position the object, for instance a ship, which carries the said apparatus, is
situated with respect to the said person.
The said apparatus, as well as the person observing the same, may be placed either
on a fixed or on a movable object and the sonorous signals produced by the said
apparatus may be of any kind whatever, as for instance a siren, whistle, bell or other
sonorous device.
If the sound is not produced at the same point but along a straight line in one
direction and then in the opposite one, this sound will become sharper or graver
according to the speed of this motion and to the position of the person observing it, as
to the line along which the sound is moving.
In this case for an observer placed on the prolongation of the line along which the
sound moves the said sound will become sharper when it moves against him and
graver when it moves away from him. The musical interval between these two
sounds depends upon the speed of the movement of the sound. This interval will
diminish as the observer leaves the prolongation of the direction of the movement of
the sonorous device and approaches the perpendicular to this direction.
observer is on this perpendicular this interval becomes equal to 0.
When the
This movement of the sound can be obtained by fixing a sonorous device which
may be a siren, whistle, bell or the like, on a driving belt or in arranging several
bodies producing the same noise or sound in a line and making them sound succes-
sively, then the height of the sound will depend upon the quickness of the successive
sounding of these bodies.
The musical interval between the sharpened and the lowered sound of the sonorous
device will be the same to persons placed on the same straight line even if on opposite
sides of the signals. To render the observer capable of distinguishing on what side of
the signals he is placed we arrange that after the end of the movement in one
direction a pause follows or that after the end of the movement of the device in one
direction a pause follows and the sounding of the natural sound of the device after
the end of the movement in the opposite direction.
If the sonorous signal is placed on a running belt the latter may be arranged to
run on a way forming a rectangle, in a vertical plane and the said signal being
arranged to remain silent when running along one side of the said rectangle.
Then, when it is running along the three other sides of the rectangle, the signal
will be perceived as if growing sharper when running along the first of these sides,

page_text: unchanged when running along the second and growing graver when running along
the third one, the said signal being always silent when running along the fourth side
of the rectangle.
Dated this 14th day of September 1898
I, EMMANUEL DRAGOUMIS, of 22, Rue de Marseille, Athens, in the Kingdom of
Greece, Gentleman, 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 of improvements in or relating to devices for producing
sonorous signals, in order to allow a person hearing them to reckon the position in
which the object, for instance a ship, carrying the said apparatus, is situated with
respect to the said person.
These apparatus are based on the principle of the diffusion of sound, the speed of
this diffusion, or the velocity of sound, being known and nearly constant. Both this
apparatus and the person observing the signals may be either on a fixed or on a
movable object, i.e. on the coast or on board ship and the sounding devices producing
the signals may be of any kind, as for instance sirens, whistles, bells or any instrument
or body producing sound or noise.
Referring to the accompanying drawing
Figure 1 is a diagrammatic view of a device formed of two apparatus intended to
produce sonorous signals, and fixed on board a ship and of several positions of the
observer.
Figure 2 shows diagrammatically a device formed of 4 sonorous signals placed on two
straight lines crossing one another.
Figure 3 shows diagrammatically a device formed of 3 sonorous signals placed at the
corners of a triangle.
•
Figure 4 shows diagrammatically a device formed of several sonorous signals placed
in a straight line and several positions of the observer.
Figure 5 shows one construction of a device formed of a movable signal, fixed to a
belt running on two pullies, and Figure 5ª is a detail view, drawn to an enlarged
scale, showing the electrical connections and bell carried by said belt.
Figure 6 shows another construction of a device formed of a movable signal fixed
to a belt running on four pullies.
In Figure 1 is represented a ship carrying two sonorous devices (signals) A and B
of the same kind or of different kinds which give dissimilar sounds. These signals
are caused, by appropriate means, to sound simultaneously and to repeat the signals
(which we suppose for a moment without duration) at regular intervals of time.
If the person hearing these signals is placed at C3 or C or on whatever point of
this line or of its prolongation, he will hear only one sound which will be the chord
of the signals A and B.
If however this person moves from C³ to C¹ passing through C2, he will hear the
signals A and B at intervals of time which will increase successively and remain
always nearly proportional to the distance from A to B multiplied by the cosine of
the angle a formed by the said line A B with the line () (2 uniting the middle of
said line A B to the position of the hearer, supposing that the line O 2 is long

page_text: -
enough with regard to A B. Supposing O C² = 3 A B, the fault made in calculating
the angle a from the value of the said interval does not exceed 1°. If for instance
the observer is placed at C² the interval of time between the sonorous signals A and B
A B
will be
=
cos. a; if therefore the observer is placed at C₁ or at Cor on whatever
point of the lines A C¹, B C or their prolongation, the interval will be
velocity of sound.
A B
if v is the
ย
It is obvious that when the interval of time between the perception of the
signals A and B increases, the interval of time between the last perception of one of
these siguals and the first perception of the new emission of the signals will decrease
and vice versa, their sum remaining constant.
If placed at C or on the same side of the line C³ C5 as the point C+, the observer
perceives the sound B before the sound A.
If he is placed at C¹ or at the opposite side of the said line C³-C5, as before, he
perceives the sound A before the sound B.
Therefore if we suppose for instance that on the ship (which we take only for the
sake of illustration) the sharp signal or say a siren is placed at the bow or at the
larboard and the deep signal or say a bell is placed at the stern or the starboard,
the person observing the signals will be able to estimate in what position the ship is
situated in respect to himself if he knows the distance A B.
We have up to the present supposed the sound of the signals to be instantaneous
or without duration. If now we ascribe to these sounds a duration say for instance
of d, it is easy to imagine what will take place. At C3 and C5 will be heard the chord
of the signals of a duration equal to d at C¹ and C the interval between the two
signals will be
A B
v
-
d the duration of each being d; in moving from C¹ to C³ the
interval will decrease gradually; at a point between C¹ and C³ the interval will be
zero, that is the one signal will be heard immediately after the other; then between
this point and C³ the two signals will coincide on a portion of their duration this
portion increases gradually and at C³ the two signals coincide in all their duration.
As two of these signals determine the position of a straight line in respect to the
observer, several signals may be made use of in order to determine the position of
different straight lines, according to the purpose to be attained. Thus for instance
four signals of dissimilar sound (Figure 2) a b mr determine more exactly the
position of, say a ship, or of a rock carrying said signals than two signals only.
Figure 3 represents three signals a m n of dissimilar sounds, situated say on the
coast; the dotted lines are perpendicular on the middle of the lines a m or m n. If
the three signals are sounded simultaneously an observer placed within the angle eof,
will hear the sound m the last; if placed outside this angle, he will hear the sound m
before the sound a or n or before both of these sounds.
If instead of the signals A and B giving dissimilar sounds they give the same sound
not simultaneously but at a determined interval of time, which we call D, any one
placed at the prolongation of the line A B (Figure 1) will hear the signals A and Bat
different intervals of time according to his position with regard to C¹ or to C+.
If B sounds first and A after an interval of time equal to D, the person who is
placed on the line B C will hear B and after an interval being D +
AB
v
, he will hear A
and the person situated on the line A C¹ will hear A and after an interval being

page_text: It is evident that if D-
A B
ย
A B
is negative, A will be heard before B by the person
A B
at Cand that if D
= 0 or D= the person towards C¹ will hear A and B
บ
ע
A B
v
together and the person towards C4 will hear first A and after a time equal to 2
will hear B. For an observer on the line C3 C the interval of time between the
signals is D.
The interval of time between the hearing of the signals A and B increases con-
stantly in passing from C¹ to C+ being always nearly equal to D +
AB
AB
D
=
v
ข
COS. a or
cos. a when the line C2 is long enough with regard to the line A B. When
therefore A and B and D and the order in which the signals are sounded are known
the position of the object carrying the signals can be determined.
In the case we are describing the signals A and B may be also of dissimilar
sounds.
It is obvious that in the cases of the Figures 3 and 4 and in any other similar
case, we can make use, instead of simultaneous signals, of signals sounded at known
intervals of time and in known succession.
.
Now, if instead of two signals as in the cases already described, we have several
signals A, c, d, o, e, f
B (Figure 4) of similar or dissimilar sounds,
placed on a straight line at predetermined equal or unequal distances, sounded at
equal or unequal intervals and of equal or unequal duration of sounding of every
signal, a person situated on the prolongation of the line A B will hear the signals on
a more or less rapid succession according as he is towards C¹ or C².
Suppose, for the sake of illustration, signals put at equal distances one from the
other (Figure 4) and sounding at equal intervals of time and suppose the interval of
time between the sounding of A and B equal to D; suppose also that the progression
is from A towards B; then the observer placed on the side of C will hear the signal
or rapidity at which the signals are heard causes to the ear a sensation analogous to
the sensation caused by the difference of pitch of musical notes.
When D =
A B
ย
'
t' (), the observer towards C2 will hear only one sound which
will be the chord of all the signals.
AB
When D< tis negative and the person towards C² will hear first B
then
v
f, e, o, d, c, A.
Then if the signals give different notes, for instance
notes becoming higher from A to B, the observer towards C¹ will hear an ascending
succession of notes and the observer towards C² a descending one.
It is clear that if we make the distances between the signals or the intervals
between the sounding of them unequal or both quantities unequal, we will have
several values of t and t¹ but the sum of all the t's will be equal to D + A B
v
and the
sum of all the t¹'s equal to D
A B
-
In adonting different interences

page_text: signals or different intervals of their sounding we may inake vary in the infinite the
produced results.
If, in the case of Figure 4, the intervals t and t¹ are short enough, the observer
will no longer hear the signals distinctly in a more or less rapid succession, but he
will hear sounds more or less high according as he is placed towards C¹ or C²
1
and being the numbers of their vibrations). Or if only t¹ is small enough, the
observer C¹ will hear a succession of signals and the observer (2 a musical sound.
If the signals after being sounded in the direction A B are afterwards sounded in
the direction B A, a person placed towards C will hear two different series of signals
the first slower than the second; the observer placed towards C² will hear also two
different series of signals, the first quicker than the second. When we speak of notes
the first observer will hear two notes, the first flatter than the second and the second
observer also two notes the first sharper than the second.
When the observer is moving from the direction C¹ C² (supposing always his
distance from the signals great enough with regard to A B) t diminishes and t¹
increases, remaining always nearly

page_text: It is obvious that in all the cases above described instead of a series of signals
on one straight line we may use several such series on different straight lines parallel
to or cutting one another according to the results to be attained.
The production of the acoustic signals described in the above lines can be realized
by different apparatus; we will describe only a small number of them as an
example.
For the production of fixed and simultaneous signals, we fix at determined points
the sonorous bodies: sirens, whistles, bells or any instrument or body capable of
producing a loud sound or noise and make them sound simultaneously by any known
means by electromagnets controlled by a commutator moved by a clockwork or an
electromotor, or by any other motor. The successive signals can likewise be acted
upon by electromagnets as in the above case or by purely mechanical means.
The commutator, which revolves in front of a disc bearing the contacts, will
regulate the frequency of the repetition of the signals. When the signals
are actuated in both directions, both observers towards C¹ and towards C2
(Figure 4) or two observers on both ends of a straight line passing through o
will hear the same note or perceive the same intervals between the signals, it is
necessary to render it possible to distinguish in which of two opposite positions the
observer finds himself. In order to attain this result, we can arrange the apparatus,
say the contacts on the disc, in such a manner that after the sonorous bodies are
actuated in one direction, a pause follows, or so that a pause follows the prolonged
sounding of the last of the sonorous bodies; or we may arrange the apparatus in such
a manner that after the signals are actuated in one direction, a pause follows, and
after the signals are actuated in the opposite direction the prolonged sounding of the
last sonorous body follows.
As for the last case, a sonorous body moving on a line, this body may be fixed on a
vehicle moved rapidly on rails, for instance by electricity, or the body may be fixed
on a driving-belt or chain (Figure 5) which revolves rapidly. In this case an observer
will hear two notes, one flattened and one sharpened note according as the sonorous
body is receding from him or approaching him.
If we arrange the driving-belt on a vertical plane on four pulleys, the axes of
which lie in the angles of a rectangle (Figure 6) and we arrange that the sonorous
body or instrument sounds during the course c d e f and is silent during the course f c
an observer placed at O¹ will hear during the course c d the sharpened note, during
the course de, the natural note of the sonorous body; during the course e f the
flattened note and during the course fc a pause will follow. To the observer at 011
the sharpened note will be followed by the pause and then by the flattened and the
natural note. Thus the two opposite positions are easily dsstinguished. During the
curved course, transitory notes will be heard. If the observer is on the line (or on
the plane) perpendicular to the plane of the apparatus (Figures 5 and 6), and passing
through o, he will hear only the natural note of the sounding body all the time that
it is sounding. If he is moving on a horizontal plane passing O between this position
and on the position 01 or 02 he will hear the sharpened and the flattened note the
interval of which will increase, when he is approaching 01 or 02 and when the
distance of the observer from o is large enough in respect to the length of
the apparatus, this interval A will be always nearly equal to
t

page_text: The sonorous body fixed on the driving-belt or chain can be actuated by different
ways. It may for instance be sounded by means of an electrical bell of usual con-
struction (Figures 5, 5 & 6). The current will be conducted in this case through
two wires u and w insulated from one another and fixed to the driving-belt ; each
of these wires u and w is in communication with one pole of the electro-magnet of
the bell 8. The said wires u and w are provided with suitable contact-pieces u
and w also fixed to the belt and the poles of a battery z are provided with suitable
brushes and 22 bearing against the said belt and causing the bell s to be sounded
each time those brushes come into contact with the said contact-pieces u¹ and w¹. In
the construction illustrated in Figure 5ª the driving belt x as well as the pulley a
are supposed to be made of insulating material.
We may also sound the sonorous body by hammers fixed around the driving-belt
and against which the body will strike in revolving.
In order to make the sonorous body revolving with the driving-belt sound, we may
also utilise the force of the air which is compressed in front of this body; the
pressure of the air which may be considerably increased by attaching a funnel to the
front of the revolving body is able to make a siren, a whistle or a vibrating plate
sound.
It is obvious that instead of one sonorous body moving on a vehicle or revolving
with a driving-belt, or chain, we may use several such bodies similar or dis-similar
moving on the same line or plane or on different lines or planes, parallel or cutting
one another according to the result to be attained.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what
I claim is:
1. An improved device for producing sonorous signals consisting of two or more
sonorous bodies giving similar or dis-similar sounds, arranged on a straight line or in
several straight lines parallel to or cutting one another and combined with a suitable
apparatus for causing these sonorous bodies to sound simultaneously or at pre-
determined intervals of time, the said sonorous bodies fixed at equal or unequal
distances one from the other, at determined points of an object movable or unmovable,
in order to allow an observer placed at a distance from this object to estimate the
position of this object with regard to himself, owing to the differences of time that
the sound issuing from these sonorous bodies will take to arrive to his ear,
substantially as shown and described.
2. device for the same purpose and based on the same principle consisting of
one or more sonorous bodies fixed on a vehicle or a driving-belt or chain, running on

page_text: suitable pulleys or other movable bearings and combined with suitable apparatus to
cause the said sonorous bodies to be sounded either continuously or at predetermined
intervals of time or on certain positions of their way substantially as and for the
purpose specified.
ד
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.