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





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



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



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

7



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.

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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. , .



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'[

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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.



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.



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.



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.



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



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



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,



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.

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Documents

Notes on Use of Telemeter Graduator