Notes on Use of Telemeter Graduator
Transcript of Notes on Use of Telemeter Graduator
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NOTES ON THE USEOTES ON THE USE
OF THEF THE
TELEMETER GRADUATORELEMETER GRADUATOR
ANDND
LISTENING-IN INSTRUMENTSISTENING-IN INSTRUMENTS
FOR MINEOR WARFAREINE WARFARE
TRANSLATED AND EDITED AT THE ARMY WAR COLLEGERANSLATED ANDEDITED AT THE ARMY WAR COLLEGE
WASHINGTON, 1917ASHINGTON, 1917
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PR:I . WASHINGTONWASHINGTON
fc I GOVERNMENT PRINTING OFFICEc I GOVERNMENT PRINTING OFFICE
15 I5 19171917
00303C
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WAR DEPARTMENT,
Washington, October 30, 1917.
The following pamphlet entitled "Notes on the use of the
Telemeter Graduator and the Listening-in Instruments for Mine
"Warfare is published for the information of all concerned.
[062.1, A. G. O.]
order of the Secretary of War :
JOHN BIDDLE,
Major General, Acting Chief of Staff.
Official
h. p. McCain,
The Adjutant General.
3
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iicimiFui
War Department,
The AdjutantGeneral's Office,
Washington, June 19,1917.
To all Officers of the Army:
You are advised that this and all subsequent documents of
a similar character, which may be furnished to you from this
office, are to be regarded as strictly confidential. They are
to be kept at all times inyour
personal possession, and arenot to be copied, nor are any parts of their contents to be com-municated either directly or indirectly to the press, nor to any
persons not in the military or naval service of the United States.
InEurope these documents are not to be carried into the front-
line trenches, nor farther to the front than the usual post of the
officers to whom issued.
Strict compliance with this injunction is enjoined upon every
officer into whose hands any of these confidential documents
may come.of the Secretaryorder of War
H. P. MCCAIN,
The Adjutant General.
5
OIIfiLASSIFIEJ
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TABLE OF CONTENTS.
Page.
I.Notice sur l'Emploi de telemetre graduateur 9—11. Appareils d'Econte pour laGuerre dcs Mines Telemeter
graduator S. P. H 9
,Principles of its use. :Principles of its use. : 9
Use of the graduator as a telemeterse of the graduator as a telemeter 100
Practicallyractically 111
1.. Equalization of the degrees of sensitivenessqualization of the degrees of sensitiveness. . 111
2.. Gauging of the instrumentauging of the instrument 111
3.. Measurement propereasurement proper TOO
Remarksemarks 122
-.Case of geophones of the field park (nonelectric instru.Case of geophones of the field park (nonelectric instru-ments)ents) 122
Remarksemarks 13311.1. Case of antennae S. Pase of antennae S. P 133
111.11. Telegeophone S. P. G. case (electric apparatus)elegeophone S. P. G. case (electric apparatus) 144
Remarksemarks 155IV.V. Central control station for 5 directions (electric apparaentral control station for 5 directions (electric appara-
tus) intended to permit listening from a command postus) intended to permit listening from a command postin 5 branches of listening galleriesn 5 branches of listening galleries 155'
Remarksemarks 166Separate instruments which can be ordered to replaceeparate instruments which can be ordered to replace
othersthers 166Note on the use of the apparatus S. Pote on the use of the apparatus S. P 166
S. P. P 166.Geophones.GeophonesSimple listeningimple listening 166
Directionirection 177
Use of the compassse of the compass 177
Remarksemarks 177
11.1. Antennae S.ntennae P. P 177
111.11. Telegeophone S. P. Gelegeophone S. P. G 188
IV.V. Central control station with 5 directions S. P. Gentral control station with 5 directions S. P. G 188use :se : 188
Simultaneous listening in 2 galleries 19
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1
,v
I.
Notice stir l'Emploi de Telemetre Gbadttatetir.
11.
APPABEILS D'EcOTTTE POtTB IAGUEKKE DES MINES.
TELEMETER GEADUATOR Si, P. H.—'Principles
ofits use. The instrument requires in operation
two telegeophones, R V (transmitters set on the ground), and
twp corresponding telephone receivers, R' V. \
t
/
\
"\
Wh§n the listener has attached the spring earpiece to the
knobs, by means of rubber tubes, he can listen either in the
receiver R' (red) or in the receiver V (green) by the operation^
of the acoustic piston commutator.Suppose, in the first place, that the group R R' (red connec-
tions) has the same sensitiveness as the group V V (green con-
nections) ; the intensity of the sounds received through, R and
V-may be compared.
22977°—17 2 9
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TELEMETER GRADUATOR.0
\ u25a0 Let O be the point where work is in progress to which it is
desirable to listen^ ra and r3r3 the distances R O and V Q.IfR is nearer than V to the point O, the sound heard in R
willbe louder than the sound heard in V, lor two reasons :,
1. The energy transmitted from O is diffused on a larger-
sphere in V than in R.
2. In the passage from the sphere of the radius ri to that of
the radius r2r2 the energy is absorbed to a less extent by the earth.
More intense sound will therefore be heard when the piston
puts the Keceiver R into connection with the ears.
The graduator of R makes itpossible to equalize the soundsv
heard by reducing the sensitiveness of the receiver R in a meas-
Fig.2.\u25a0•\u25a0\u25a0 lu25a0 R
'-'•.
urable proportion by means of a tap with a long stem placed onthe course of the sound from R t6 the ears.
Use of the graduator as a telemeter.— One of the possible uses
61^ the instrument is measuring the distance, at which a source of;sound O is located.
The line*R V of the telegeophones is aligned approximately
with the source of the sound.
Thedistance
R V willbe called the base and designated by "6.The relationship of the intensities recorded depends, when the
degrees of sensitiveness are equal, upon the distance from the,
"
sound Oto R only.1 .,i
iLetabe the sound produced at O. The sound recorded at R willheii-a*(r)ii=a<p(n)
vj(ti)being an unknown function which depends upon the nature of the terrain.s At V there willbe received—
ie=avs(n+J)
and
ii <p(n) 'U vin+s) Iln
f(n) is an unknown function which willbe determined by gauging, this functionbeing valid only lor a given yalue 8 of the base.
This relation willbe measured by the reduction of the sensitiveness which should->be applied to the receiver Rto obtain equality. , .
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f$
•TELEMETER GRADTTATOR. 11
.u25a0\u25a0t
The relation between the reduction of the sensitiveness ands
the, distance O R willbe found by a preliminary gauging on a
terrain of the same nature as that where the listening is to takeplace. \u25a0\u25a0'*\u25a0'—
Practically. The measuring of a distance involves preliminary, *,,:
operations which can be made in advance, at leisure, and which—\" the equalization of the degrees of sensi-
require a certain time'
\u25a0
\u25a0tiveness and the gauging. r1. Equalization of the degrees of sensitiveness.— The degrees .-
of sensitiveness of the telegeophones vary with each instrument. „
An equality in the degrees of sensitiveness may be obtained in >\u0084
the followingmanner, however :Two telegeophones, attached to >
the red and green binding posts, are set on the ground a short __/,V"'> - '
distance apart (50 centimeters), and some one taps with his' - '-*
finger on the ground at the middle of this distance. The gradu- c'ators of R' and V are opened to their widest extent. If the v -^louder -sound corresponds to V , it follows that V is the most
sensitive, and the graduator of V is1 closed until equality is..-. "/;
Fiq.Z.V R
J2" 4" 6"
established. If the louder sound corresponds to R', the twotelegeophones are inverted and the same operation is performed.
r '''••The graduator of V is not again touched.—
2, Gauging of the instrument. A base Bis selected (practice'
jf;-
shows in each case the appropriate dimension of thisbase). •_
-\-*'\u25a0Wfth the two telegeophones set on the ground, some one t^ps t
withhis finger on the ground on the line R V at 2 meters fromR.
Jf a louder sound is heard in R', the graduator R' is adjusted • r,'for establishing the equality. A mark is made with a pencil •
on the ground glass 2 meters in front of the point. The same-
is done at 4 meters, 6 meters, etc. The instrument is then
gauged for that particular terrain. j
A base of from 2 to 3 meters is generally suitable up to dis
tances of Bto 10 meters. , i\u25a0i"-These preliminary measurements are made in advance, once ;
for all, but the equality of sensitiveness must be checked up from -, ?time to time. Ifithas changed a little,which may be perceived - '"T'by having the ground tapped midway between R and V, th» -; "«\u25a0'[
«'rjn
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12
sensitiveness is restored to a condition of equality by slight
adjustments of the graduator of V .—3. Measurement proper. -The measurement proper is very
rapid and requires only a few seconds. R V are aligned with the
sound, R being nearer the sound.
Listen while maneuvering the piston. Then work the gradu
ator of R' so as to obtain equality. The distance to he measured
is read on the graduation made.—Remarks. 1. The telegeophone 1917 permits only of the use
of the telemeter graduator. The 1916 model (inclined model)
does not have a sensitiveness unaffected by the weather.2. Inspect frequently the state of the batteries.
3. Never try to dismount the receivers and graduator
I.
CASE OF GEOPHONES OF THE FIELD PARK (NONELECTRIC INSTRU
MENTS
Instruments and operator stationed at the extremity of the
gallery or listening gallery.
This case includes :
(1) 2 geophones S. P. (S. P. (=Section de Pare de Oam-
pagne)=Field Park.)
(2) 4 rubber tubes, 0.90 meter long.
(3) 2 double-spring earpieces.
(4) 1compass mounted on a board.
Weight: 2.1 kilograms.
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13TELEMETER GRADUATOR.—Remarks. 1. The geophones should not in any case be dis-
mounted. The instruments will be sent to the Central Estab-
lishment for repairs.2. The instruments bear a number repeated on the case. They
are grouped in pairs at the time of shipment. Apparatus be-
longing to different pairs are not interchangeable.
11.
CASE OF ANTENNAE S. P.
A nonelectric instrument intended for receiving the sound at
the extremity of a boring.
Operator stationed at the orifice of the boring.
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14 TELEMETER GRADUATOR.
This case contains:
(1 ) 1 geophone on a geophpne-carrying stick.
(2) 12 sticks, 1.15 meters long, 1 terminated by the Boundreceiving knob and a 0.60-meter stick.
(3) 1 double-spring earpiece
tubes,4) 2 rubber 0.90 meter lon
Weight: 12.9 kilograms
111.
(ELECTRIC APPARATUS).ELEGEOPHONE S. P. G. CASE
Instrument placed at the extremity of the branch or listenin
gallery.
Operator stationed outside the system of mines.
This case contains:
(1) 1 elegeophone S. P. G.(2 ) 3 batteries (T . M. O .) mounted in series.
(3) 1 special telephone receiver, with knobs and sound re
ducer.
(4) 2 rubber tubes, 0.45 meter long.
(5) 1 double-spring earpiece.
Weight :3.26 kilograms.
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15TELEMETER GRADTTATOR.—
Remarks. 1. The case is always delivered with125 meters ofcable, double conductor, mounted on a wire-board spindle, and
contained in an infantry haversack of the usual design.
2. On request, the teJegeophone can be delivered in a watertight zinc box when it is to remain in water.
3. The telegeophone must never be dismounted. Repairs aremade at the Central Establishment.
1\
(ELECTRICCENTRAL CONTROL STATION FOR DIRECTIONS APPA
BATUS), INTENDED TO PEBMIT LISTENINGISTENING FROM A COMMAND POS'l
IN 5 BRANCHES OR LISTENING GALLERIES
The case contains
(1) 6 telegeophones S. P. O(2) 1 switchboard for 5 direction
(3 ) 6 batteries (T . M. O.).
(4) 2 special telephone receivers, with knobs and sound re-ducer.
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16 TELEMETER GRADTJATOR.
(5) 4 rubber tubes 0.45 meter long.
(6) 2 double spring earpieces.
(7) 1 screw driver, 1 roll of chatterton, 1 small reserve offlexible wire for interior connections.
(8) -1 voltmeter.
Weight :14 kilograms.—Remarks. 1. The case is delivered with 5 coils of 125 meters
of cable, double conductors, mounted on wire-board spindles and
each contained in a canvas haversack.
2. On request, the telegeophones can be delivered in watertight zinc boxes when they are to remain in water.
3. The telegeophone never ought to be dismounted ;the repairs
are made at the Central Establishment.
SEPARATE INSTRUMENTS WHICH CAN BE ORDEKED TO REPLACE
. .'
\u25a0- OTHERS.
(1) Compass mounted on a board (see Fig. No. 1).
(2) Rubber tubes 0.90 meter long (see Fig. No. 1).
(3) Double-spring earpiece (see Figs. Nos. 1, 2, 3, 4).
(4) Geophone mounted on. a geophone-carrying stick (see Fig.
No. 2).
(5) Sticks for the case of antennae (see Fig. No. 2).
(6) Telegeophone S. PT G. (see Figs. Nos. 3 and 4).
(7) Batteries (T.M. O.).
(8) Rubber tubes,0.45 meter
long.
(9) Coils of double cable, 125 meters long, with wire-board
spindle and haversack.The geophones (Fig. 1) being grouped in pairs, are only de
livered in pairs and with their box (complete box of geophones).
NOTE ON THE USE OF THE APPARATUS S. P.
I.
GEOPHONES S. P.—Simple listening. The case contains two numbered geophones.
Each can be used separately, which makes it possible tomultiplythe listening stations. The two nipples are then fitted withtubes terminating in metal tips, which are placed in the ears in
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17ELEMETER GRADUATOR.
such a way that they are pointed forward. For use, the geophoue
is set on the ground or held flat with the hand against a per-
pendicular surface.Direction.— -When a suspicious sound is heard the two geo-
phones are necessary for determining its direction. In this
ease only one nipple of each of them can be used (the one which
is nearer the earth or the perpendicular supporting surface).
The other willremain closed to avoid the introduction of earth
into the instrument and also to avoid the alteration of the
sounds. Itis essential that the two rubber tubes be of the samelength. Do not interchange the instruments of two eases s
—Use of the compass. Orient the points of the compass board
toward the centers of the geophones, turning the black arrow
engraved on the compass board toward the sound. Wait until
the needle is quite still, then clamp it, thus permitting movement of the compass board for readings or verifications.
Read the number indicated by the north point (blue) of the
needle. Notice whether this number is on the left side (marked
G) or on the right side (marked D) of the compass board. If,
for instance, 3 to the right is read, itmeans that the (magnetic)north is 30° to the right of the sound, or that the sound is 30°to left of north. If11° to left is read, itmeans that north is 110°to left of the sound.
—Remarks. Itis essential that every nipple that is not in use
should remain closed, even while the instrument is being carried about (specially ifthe instrument is in a pocket). Ifdust
has gotten into it, be careful not to drive it further in, but hold
up the instrument with the nipple down and carefully let the
dust fall out.
Ascertain from time to time, by blowing into the tubes, whether
they are blocked. Inspect carefully in this respect the tubes of
the spring listening instruments. If they are blocked, clear
them with a pipe cleaner, which is introduced (the nonbarbed
end first) through the vulcanized rubber tip. Keep the tips (and
the ears) perfectly clean.
Never dismount the instruments.
11.
ANTENNAE S. P.
The sticks will be screwed together end to end as they are
extended into the boring. The geophone carrier handle will be
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18 TELEMETER GRADTTATOR.
screwed on last. The knob forming the earth connection willbe
introduced first, and will finally be in position at the extremity
of the boring. A pressure exerted at the other end of theantenna willassure contact with the ground. Itwillbe arranged
so that the geophone carrier willbe at the orifice of the boring.
Like a telephone line, the antenna of wood willnot operate if
it is broken. It is absolutely essential that the contact through
wood should be complete from one section to another from oneend of the antenna to the other. For this purpose it is sufficientto screw the sections tightly together, taking care that there
is neither dirt nor a vacant space between sticks.
111.
TELEGEOPHONE S. P. G.
Place the telegeophone in the gallery, the small end always" " "horizontal. Note the indications high and low," and
whether it is a question of listening to noises from the ground
or those coming from a vertical surface against which the instru-
ment is placed. Then give it a few taps with the finger.Connect the two binding posts with the extremities of a double
wire, the other ends of which are fastened to the binding posts
Li, Ij2 of the box.
The two rubber tubes are fastened at one end to the knobs of
the receiver and at the other to the spring listening piece, the
tips of which are introduced into the ears. The curved part of
these tips is placed in such a way that the point is directed
forward. Open completely the reducing valve (vertical position)
and close the current with the compass switch. Avoid, carefully,
letting the current flow while the instrument is not in use.
In case distant sounds would interfere with listening, partly
close the valve.
IV.
CENTRAL CONTROL STATION WITH 5 DIRECTIONS S. P. G.—Use. Place the telegeophones in the galleries, resting solidly" " "
on their little bases. Note the indications high and low."
Tap the instrument with the finger. Fasten the binding posts
of each telegeophone to the extremity of a double wire, the
other end of which is bound to the binding posts (1), (2), (3),
(4), (5) of the switchboard,
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19TELEMETER GRADTJATOR.
Mount two rubber tubes on a spring earpiece, the other ends
of the tubes being attached to the knobs of a receiver Fi or F 2
.- Place the plug corresponding to a receiver in the spring jack
of the telegeophone with which you wish to listen.—Simultaneous listening in two galleries. Incase itis desirable
to compare the sounds received by two telegeophones, apply oneof the rubber tubes of an earpiece to one knob of the receiver
Fi, the other to a knob of the receiver F2,the unused knobs being
closed with two little plugs. Assure yourself at once that it is
the same sound that is heard in Fi and F2. The comparison of
the intensities then gives an indication of the relative distanceof the source of the sound from the two telegeophones used.
Ifit is desired to reduce the sensitiveness, close gradually the
valves. The cover of the batteries may be used as switch desk.
Test frequently the voltage of the batteries. Never forget to
withdraw the plugs from the switchboard during the intervals
between listening, to avoid the rapid exhaustion of the batteries.—N. B. The Central Establishment for Special Engineers' Mate-
rial furnishes, on request, a detailed Notice on Sound Perception
of Mines, containing, especially, instruction on the installation
of the listening schools.Orders are filledby the Central Establishment of the Engineers'
Material (E . C. M. S.), 39 Hue de Bellechasse, Paris.
Instruments requiring repairs should be sent to the Central
Establishment.
Pabis, 1916.
o