CHAPTER IIISECTOR AND TRENCH DUTIES
Definition.The Plan of Defense contains all the different duties necessary to make a proper defense of the position. The execution of these duties is the execution of the Plan of Defense, which follows logically and depends directly upon the Plan of Organization.
Principles of the Plan of Defense.(a) The most important principle of organization of a position is thedisposition of troops in depth. It is necessary to have plenty of support and reserve units disposed one behind the other. Only one-sixth to one-third of a garrison in the support point of the first line remains in the trenches for the purpose of observation and security. The rest remain in the rear as a reserve for reinforcements or counterattacks.
(b) Each trench, each nest of resistance,each area of the ground, must have a responsible leader.The garrison of any such area must never leave the ground allotted to its defense under any conditions of battle.The defense must be carried out by this garrison on the lines originally laid out. A leader is not allowed to fall back on troops in his rear or to take up a better position. The troops in depth are placed there for the purpose of reinforcements for the lines in front.
(c)Each part of a position that is lost to the enemy must be immediately retaken by a counterattackcarried out by troops held in reserve. The first line is retaken by reserve troops in the support line, and similarly, if the support line is lost, it must be retaken by reserve troops held in the third line. If all three lines are captured, an attempt must be made to retake the third line by the reserve troops of the sector.
Form of Plan of Defense.In each division of the position from front to rear there must be a Plan of Defense. This plan always contains the five following elements:
Guard Duties (Security).Security is obtained by the use of sentinels and patrols.
Sentinelsmust not be confused with observers, watchers, or snipers. Observers belong to the information service of the sector and are not on duty at night. Snipers operate only in the daytime. The watchers of the different lines give the alarm in case of an attack, and are on duty both day and night. Sentinels are posted in the first line or in advanced posts. Their work and number willdepend upon the proximity of the enemy, the tactical situation, and above all upon the conditions of the wire entanglements out in front.
At night, one sentinel is posted, say, for example, every 10 yards in the fire trench of the first line. During the day, only enough sentinels are posted so that all parts of “No Man’s Land” can be observed. This will allow a maximum number of men to rest.
In the firing line, the sentinels work in three reliefs. When not on guard duty, they sleep. The remainder of the garrison in the cover trench, however, are available for work, for patrols, and to furnish supply parties. Sentinels should have their rifles resting on the parapet close at hand, ready to fire at a moment’s notice.
By day, the sentinels use a periscope or observe through a loophole. This practice is, however, strictly prohibited at night, when a, sentinel must observe over the parapet. As little challenging as possible is done, and then only in a very low tone.
Reconnoitering Patrolsare the best means for security against attack. Every night the commanders of the support points or the centers of resistance send out patrols in front of the firing line. The strength of a patrolmust be sufficient to carry back a wounded man,i. e., the number should be five, six, or more. The success of a patrol depends entirely upon the leader. He must be clever, daring, and observant, and the rest of the patrol is simply his bodyguard. He himself must observe the objective of the mission of the patrol.
Patrols should never be sent out without definite orders as to their mission. Such may be, for example, a reconnaissance of the enemy’s lines, to discover if the enemy has cut passages in his wire belt preparatory to an attack, to examine their own wire entanglements, etc.
The route of the patrol must be exactly determined; also the hour of departure and return designated. Word is passed along the line of sentinels that a patrol is out in front with the necessary information about the same. The preparation for a night patrol must be made during daylight.
Officer of the Watch.In the firing line the company commander arranges a roster of his officers for duty as officer of the watch. Also in each platoon the platoon commander will detail a N. C. O. of the watch. The officer of the watch is responsible for the duties of observation and security, and is especiallyresponsible for the giving of the alarm in case of an attack and consequently for the calling of the artillery barrage by use of rockets, signals, etc.
Standing to Arms.It is of the greatest importance that the troops in the first line are thoroughly trained in taking their positions when the alarm is given as quickly as possible, without confusion. The alarm is often given for practice in order to ascertain the amount of time it will take the men to reach their places in the firing line.
The command “Stand to” is usually given one hour before daylight and one hour before dark. At this time the company commanders arrange for inspection of arms, ammunition, and equipment by the platoon commanders.
Observers’ Duties.Every effort should be made to obtain information of the enemy, his trenches, and his wire entanglements. Any alteration in the enemy’s lines must immediately be reported. The importance of forwarding such information must be impressed upon all ranks. This duty is carried out by observers.
All men of the company are used as sentinels in the first line or as watchers in other lines, but not all are observers. Men who are to act as observers receive special training.A man to become an observer must have a special capacity for this task.
Each platoon should have at least six such observers, enough for proper reliefs.
The observers are placed:
1. In each company the observers are distributed in a number of observation posts properly camouflaged so as not to be discovered by the enemy. These posts may be in advance of the firing line, in the firing line, or at any point within the position that has a wide view of the front. The observers employ periscopes or field glasses. Everything of note that is observed is recorded and from these data the captain makes out his daily observation report.
2. Also in the sector there are 2 or 3 observatories from which the information is turned in directly to the colonel. These posts must be properly concealed and protected. In each one of these we find the following:
(a) Regulations posted that give the personnel, tour of duty, sector of observation, direction to special points of interest, and certain precautionary measures.
(b) Specially prepared blank forms upon which to record information gained by observation.
(c) Field glasses, maps and sketches, and panoramic views of the ground in front, both visible and invisible from the observation posts.
(d) A telephone connecting the post with the nearest command post (center of resistance or sector).
The observers in these posts are directly under command of the intelligence officers of the regiment and are of a special personnel. They must be thoroughly familiar with the regulations of the posts, maps, panorama, etc.
The intelligence officer collects and coordinates all information gathered in the sector. Every morning he turns in a consolidated report made up from the information in the captains’ daily reports and from the records of the sector observatories. (In order to avoid confusion of the different daily reports these information records are kept on two different colored blanks, red and blue alternating each day.)
The report of the intelligence officer is signed by the colonel and sent on to the brigade headquarters. From the data of his complete report the intelligence officer very often must verify certain information by the use of patrols. For this purpose he makes a request upon the colonel for special patrols.
Information is gathered from both airplanes and ground observatories. From ground observatories it is attempted to obtain the following data;
1. To ascertain the intentions of the enemy.
2. To properly prosecute attrition of the enemy’s works.
Attrition.By the word attrition in fighting is meant the gradual destruction of the enemy’s morale and strength, and demolition, little by little, of the enemy’s position. Trench warfare is not a rest or simply a time for guard duty. It is a phase of the battle in which you must do as much damage to the enemy as possible.
This work will also keep up the offensive spirit. For this purpose different means are used:
(a) Sniping: Each company in the first line uses its best shots as snipers. A sniper must be a good observer and he must depend upon his keen eye for evidences of the enemy, such as smoke of cigarette or the glint of a bayonet, giving proof of the presence of an enemy. Especially during hostile shelling will a too curious enemy come to his loopholes to observe the effect of the same. This is the sniper’s chance.
In each center of resistance the snipers are placed under the command of a sniping officer. He makes the rounds of the snipers’ posts once or twice a day, and submits a daily report containing known casualties of the enemy, location of the number of snipers’ posts, telescope rifles, fixed rifles, and rifle batteries.
(b) Infantry Weapons: Besides sniping, all the other infantry weapons are used to assist attrition of the enemy. Hand and rifle grenades are thrown on special points of the hostile line. A battery of hand or rifle grenadiers properly disposed can very often carry out a concentrated surprise fire on an enemy’s salient or advanced post. Automatic and machine guns are always used for this purpose and especially at night. They are trained on supply routes, road junctions, etc., and by use of sudden bursts of fire at irregular intervals they will compel the enemy’s supply parties to continue their transportation in the boyaux instead of on the open ground.
The use of indirect machine gun fire is very depressing to the enemy. Such judicious employment of machine guns is sometimes more effective than severe artillery shelling.
The 37 mm. gun, which is also an infantry weapon, is used principally against hostilemachine gun emplacements. The location of this gun must be constantly changed.
(c) Use of Artillery Weapons: Besides furnishing barrage fire against hostile attacks, the artillery can be called upon for surprise fire on working parties, harassing fire during the night against supply parties and their routes, and also for reply fire against hostile shelling.
Trench mortars and other engines keep the enemy as uncomfortable as possible at all times.
(d) Fighting Patrols and Raids: Fighting patrols and raids are used with the express purpose of causing loss and damage to the enemy. This is accomplished by engaging the enemy’s patrol and working parties or by raiding his saps, listening posts, or trenches. Such operations must not, however, degenerate into frivolous local fighting, causing loss of men and waste of artillery ammunition.
Work.Daily trench work consists of (1) maintenance and (2) new construction.
(a) Maintenance: The daily work of maintaining the elements of the position is considerable, and its importance often escapes those responsible for the same. They are:
Repair of parapets, boyaux, and shelters damaged by bombardment, water, or frost.
Replacing or completing accessory defenses, revetments, ammunition recesses, emplacement of machine guns, observation posts, depots, etc.
Cleaning and Draining of Trenches and Boyaux: The garrison of each area is responsible for their own maintenance work, which is done usually during daylight hours. Sometimes during severe bombardments this repair and maintenance work becomes too great for the garrison and workmen have to be called in to help.
(b) New Construction: New elements of the position are constructed in carrying out the Plan of Organization. These are usually carried out at night. This work is carried out by troops in the doubling trench, the support line, or detachments of workmen from the reserve of the sector. There may also be special parties from the headquarters detachment of pioneers or of the engineer battalion of the brigade.
For all these special works the personnel for whom they are built must be present during the construction to furnish necessary information and for inspection. A machine gun crew helps in building its emplacement; the intelligence officer directs the construction of his observatories. The medical officerpresent during the work on the medical aid station; the telephone officer superintends the establishment of his telephone exchange, etc.
The battalion commander is responsible for all the work done in his center of resistance, and in conjunction with the sector leader draws up a time-table for the work.
All this work must be continued by each succeeding relief. When a new unit takes its turn in the trenches the orders and plans of new works are turned over to its commander.
Arms, Equipment, and Ammunition.Full equipment will always be worn in the firing trench, except the haversack, water bottle, and entrenching tool. In the support and reserve trenches the equipment to be worn is subject to the will of the sector commander. Every man will always carry a gas mask in any part of the position and even as far to the rear as ten miles.
The men in the firing line and in the doubling trenches will at all times be in possession of their rifles and bayonets. The rifles of men in the support and reserve trenches may be kept in protected racks in the same shelter as the men.
All rifles must be kept scrupulously clean at all times.
Ammunition is protected from bad weatherby being placed in boxes located in the sides of the trenches.
Ten to twenty hand grenades are placed in a sandbag. These are usually kept at the depot and carried in these quantities for the supply of the fire trench in combat. One or two of such sandbags are kept at a bombing post.
Special care must be taken to keep rockets in good condition. Supplies are kept in the fire line (platoon leaders’ posts, observations) and at points in the rear (in the observatories or different command posts or in the observation posts of the information service).
Depots and Supply.(a) Depots:—There should be one general depot in each area located near the command post of the chief of area. However, in order to facilitate work in the first line the platoon leaders may establish near their post a small depot of tools and material being used for the time being. The importance of the depot depends upon the area it is to supply. For example, the depot of the garrison of a support point in the first line would contain:
The depot at the center of resistance contains the same articles but in greater number, also telephone wire, blankets, and three days’ rations of food.
The main depot of the position, however, is the one near the command post of the leader of the sector. It is divided into three parts:
1. Ammunition and rocket signals (Ordnance Service).
2. Material of every sort (Engineer Service).
3. Food and clothing (Quartermaster Service).
The different services in the rear of the position maintain the supplies of the sector depot. The amount of ammunition to be carried is fixed by orders from the general and this amount must be strictly maintained.
_Organization of Supply System._
(b) Requests for Supplies: Each morning the chiefs of areas send in a request for material required for the next night’s work. All these requests in a sector are grouped by a staff officer under the heads of the three different services. Along with each request must go the information showing necessity for same. Emergency requests are made by telephone. The officer making request for material must be on hand to receive and check the same upon delivery.
(c) Supply Parties: The supply of the depot is usually made with special detachments taken from the support or reserve companies. If it is necessary to take men from the front trenches for this purpose, no more than 10% can be taken away from these trenches at the same time. Complete units will be used as supply parties with their leader if possible. Upon each battalion in a C. of R. and upon each regimental reserve falls part of the responsibility of distributing supplies in the rear of the sector. The unloading or rendezvous points are disposed along what is called the supply line, usually on a road, path, ravine, behind a hill, etc. Supply parties sent out at night to these points make as little noise as possible. They return along a well-picketed path, usually running along one of the central boyaux. Transportation is thus carried in the open ground as far as possible, usually to the support line.
When proper protection is possible, pack trains are used to carry supplies right through the distributing point and up to the depots of the sector.
(d) Cooking: The battalion kitchens are located behind the sector in a protected emplacement. Steps must be taken to ensure as little smoke as possible being seen from them. At night each platoon sends a ration party to the kitchen.
When the regiment has rolling kitchens, these are brought up part of the way towards the sector where they meet the ration party. Arrangements should be made to always have, if possible, some hot soup or drink available for the men between midnight and 4 a. m.
(a) Activities of the Troops: Sector duties include a considerable amount of work, and are not only useful from a tactical point of view, but are also indispensable for the moral and physical welfare of the troops. Men without occupation in the trenches stagnate, grow slack, and think only of the time when their relief will arrive. Such troops lose their aggressiveness, so that when the time for the offensive arrives they have no confidence and cannot deliver the proper blow.
Good practice to obtain fruitful results is the employment of time as follows: Ineach company the captain prepares a daily schedule of duties in which he allots the different services of the strong point: hours of “standing to” and inspection, of sending ration and supply parties, time of rest, of cleaning arms, equipment, and clothing, time of trench work, etc. This schedule is communicated daily to each platoon at a regular hour.
(b) Discipline in the Trenches:—Life in the trenches is not especially dangerous when all precautions are observed. In the presence of an alert enemy, every faulty move of disposition receives its punishment, such as the improper concealment of a movement, poorly hidden trench work, or useless noise in the firing line. Silence is one of the essential rules of the trench. Silence in a sector in which troops are properly disciplined enables the chief to rapidly transmit his orders and the men to accomplish same without delay.
Daily Reports:—In each sector, from the captain up, the different commanders must furnish a daily report. These are co-ordinated in the headquarters of the sector commander, and afterwards sent to the division headquarters.
(a) Telephone Reports:—
These reports contain the main events of the time covered. Similar messages are sent at any time important events occur, such as heavy shelling, important information of the enemy, activities in the air, etc.
(b) Written Reports:—The daily morning written reports contain the following paragraphs.
1. General aspect of the sector.
2. Important events of the day.
(The events must be reported in detail, for example: A report of shelling must contain the details as to the area bombarded, the caliber of the gun used, and the time and direction of same, etc.)
3. Casualties (wounded, killed, and missing).
4. Consumption of ammunition.
5. Requests for miscellaneous equipment and material.
This report is signed by the chiefs of the area responsible for the information in the report. Along with this official report is added a second written report with the following paragraphs:
1. Request for materials for the night.
2. Observation and information reports (to the Intelligence Officer).
3. Report of all the work done in the sector,including time schedule of the center of resistance.
Machine Guns.The tactical use and location of machine guns in the sector depends upon the following two points:
(a) Machine gun emplacements must be thoroughly concealed and during the bombardment the M. G. itself is kept under cover in a dugout. Previous to an attack of the enemy, his artillery searches the position for the destruction of the machine guns and their emplacements, because they are the most powerful weapons of the defense.
If invisible casemates can be constructed this practice is good. The best method is, however, to prepare several emplacements, properly camouflaged, with a deep dugout near at hand for the protection of the M. G. and its crew. This shelter must be located at such a point that the M. G. can be quickly brought out to any one of its emplacements when the attack develops. These emplacements usually are simple pits located in front of the trench and connected with the dugout by a gallery. When emplacements are destroyedby hostile artillery fire, or when they are not possible, machine guns are pushed into shell holes or operated on the open ground. Shell holes out in front give the best service as emplacements for a daring M. G. crew. The French success at Verdun depended to a great extent upon the judicious use of shell holes for M. G. flanking fire.
(b) Machine guns are not only located in the first line, but are disposed throughout the interior of the position. The hostile artillery may entirely destroy the first line of defenses, but the proper disposition of machine guns for flanking fire in the interior lines will prevent the enemy’s progress after penetrating the position. Machine guns are so located in the position as to cover all the space between the different lines with flanking fire. Usually three pickets define the sector to be covered by any one M. G., one at the M. G. and two limiting its sector of fire.
In a sector, ⅓ of the machine guns are located in, or near the first line, ⅓ is disposed of in the support line or in the redoubt. The last ⅓ is assigned to the third line. In each line machine guns are under the command of the chief of the area.
As a general rule, in the first line, automatic-machinerifles, because of their mobility, are used instead of machine guns.
Standing orders are, that M. G. crews will never surrender, but fight to the last man. Often the tenacity of a M. G. crew has permitted the retaking of an area otherwise lost.
Trench Mortars.In each sector there are located a certain number of trench mortars. These are efficient weapons, but must be used with care, because they will nearly always draw concentrated artillery fire.
They are used for the destruction of special points in the enemy’s lines that the artillery cannot reach.
They are employed in the preparation for an offensive against the enemy’s first line, either for an attack or for a raid. They are used for reply fire against enemy’s trench mortars.
They participate in establishing barrages.
The efficiency of trench mortars cannot be overestimated, but at the same time, great precaution must be taken in their use and concealment. The personnel required to serve the light trench mortars are taken from the garrison of the sector and belong to a special headquarters unit, a platoon of bombardiers.
The large trench mortars are commandedby an artillery officer who keeps himself constantly in liaison with the commander of the center of resistance. He consults the latter on the location of his mortars and especially upon their use. He also reports to the commander of the center of resistance all orders he receives from his artillery chief. This artillery officer always works in co-operation with the chief of his area, who in turn gives him all necessary information and help. Especially does the mortar commander require help for the supply of ammunition.
Composition of the Artillery Support.The light artillery of this sector is not directly under the command of the Division Commander. The Commanding Officer of the light artillery, usually a Colonel, in co-operation with the chief of the sector, divides it into different parts, assigning one to each of the centers of resistance. This artillery is called support artillery. As we shall see later this practice is usually the same in the offensive.
The amount of artillery allotted as support depends upon the tactical situation, in other words, the activity of the enemy.
In the Verdun and Champagne offensives the disposition of light artillery was the same in principle as that for the defensive, that is to say, one troop of artillery consisting of 3 batteries was assigned to each infantry battalion.
The general use of this artillery, is:
(a) To protect the infantry with barrage fire.
(b) Prosecution of destruction of the enemy’s personnel and works.
Tactical Liaison between Infantry and Orderly.To carry out its functions, the artillery support must be in perfect liaison with the infantry, and only when this is done is co-operation of the two arms possible. This liaison is obtained by the following five means:
(a) Organization of Leadership:—For the full co-operation of the infantry and artillery, the latter is not kept entirely independent, but is divided and assigned to infantry unit. Each chief of sector and each chief of center of resistance knows what artillery must support him if he needs it. The commander of the artillery support is not exactly under the command of the infantry chief of area, but he is at the latter’s disposal for certain calls for support fire. The proper co-operation of these two officers will give efficient results.
(b) Relation between Artillery and Infantry Commanders:—The best of relations must be established between the artillery and infantry commanders. Usually, it is not possible to locate the commanding posts of the two officers close together. Each has his area or unit to command and for that purpose must be located for the proper control of the same. The support artillery commander, however, should make frequent visits to the infantry leader and his area. He should also send his subordinate artillery officers into the infantry area to become acquainted with the first line, the conditions in “No Man’s Land,” the enemy’s lines, and to gather all the information possible from the infantry officers in the trenches. Everything should be done to foster good relations between the infantry and their support artillery and this is best done by frequent visits of the artillery officers to the infantry trenches to gather information for artillery data.
(c) Communication of Orders:—It is necessary that the orders received by the infantry commander be communicated in whole or in part to the artillery commander, and vice versa. For instance, if the chief of area receives orders to send out a fighting patrol or a raid, this information is sent to the artillerycommander, who, in turn, sends back his plan of action. Similarly, when the artillery commander expects to carry out special fires not called for by the infantry, such as destructive shelling, harassing fires, etc., he should first notify his infantry chief of area.
Similarly, any useful information picked up, either by the infantry or artillery, must be communicated to the other. The daily report of the chief of sector and the observation report of the Intelligence Officer are sent direct to the commander of the artillery support. Valuable information obtained at the artillery observation posts is sent to the infantry.
(d) Means of Communication:—The principal of the organization of the different means of communication is such as to assure the best liaison between the two arms. Telephone lines, searchlight signals, runners, etc., are established directly between a unit of infantry and its artillery support. This is to avoid loss of time and useless interruption between leaders.
(e) Detachments for Liaison and Observation:—For more efficient liaison between the artillery and the infantry, usually a certain number of artillerymen are sent from the group of the artillery Support to the infantry in their area. Usually a special detachment of artillerymen is sent. This detachment is made up of one officer, chief of the detachment, who is sent to the chief of sector, one N. C. O. to each chief of a center of resistance, the rest as telephone operators and artillery orderlies. This disposition of artillerymen in the infantry area is obligatory for an attack, but it is so practical that it is now employed in the sector organization.
The task of these artillery officers or N. C. O. is:—
(1) To control all means of communication with the batteries of the artillery support.
(2) To transmit to the artillery the different calls for fire, and in technical terms to give the proper data for the laying of the pieces on the target, and the kind of fire required.
Use of Artillery Support.Different kinds of fire are executed by the artillery support. The most important is the barrage.
Barrage.Purpose:—The purpose of a barrage is to stop a hostile attack before it can get started, or to hinder enemies’ reinforcements or reserve troops from coming forward.
Form:—The barrage is a curtain of fire let down in “No Man’s Land” as close in front of your first line as possible without loss to your own garrison. This will be about 150 or 200 yards to the front, between the two lines of trenches.
LOCATION OF ARTILLERY FOR BARRAGE
LOCATION OF ARTILLERY FOR BARRAGE
LOCATION OF ARTILLERY FOR BARRAGE
Front of the Barrage:—The barrage has real value only if it is impassible. This will be if the density of the fire is so great that the danger zones of the explosions of the individual shells overlap each other. The allotting of one troop of artillery, 12 guns, for an infantry battalion is quite sufficient for this purpose if the front of the battalion does not exceed the average length of from 400 to 600 yards.
Duration:—The barrage is a burst of fire which lasts from six to ten minutes. At the beginning the fire is very rapid and towards the end becomes slower. For instance, for the first six minutes the fire may be six rounds per gun and in the last four minutes, say, four rounds per gun. Successive barrages can be carried out depending upon the needs of the infantry.
Calling for the Barrage:—Barrage fire, for the best results, must open up at the moment the hostile attack begins. To accomplish this the call for the barrage must be made by an observer in the first line. For this reason every officer in the first line has the authority to call for the barrage. The barrage is the only fire that can be called for automatically by signal.
The kind and color of the rocket signifies the type of barrage required and the front it is to cover. In order to avoid mistakes this rocket signal is repeated from some point farther to the rear, usually at the observatories of the command post of the center of resistance, or of the sector. Rocket signals are repeated until the barrage fire opens.
Confirmation of the barrage is given by telephone, if possible. However, at the first signal rocket the artillery is required to open up the barrage fire as quickly as possible without waiting for confirmation. Barrage fire is at the disposal of the infantry and cannot be refused by the commander of the artillery, whether it is justified or not.
Other Kinds of Artillery Fires.The commanders of the center of resistance or of the sector may call on the artillery support for other fires besides the barrage, such as:
Reprisal fire on the enemy’s lines.
Reply fire to hostile shelling.
Surprise fire on supply attachments or working parties.
Destruction fire on special points.
All these fires are called for by telephone, but do not follow automatically like the barrage fire. The artillery commander, in such case, can use a certain amount of discretionwhether these fires should be carried out or not. Last of all there is the counter-preparation fire, which is a strong shelling of the enemy’s position. It is carried out as a reply to a methodical bombardment of the enemy preliminary to his offensive. It is the best means to prevent a hostile attack. If this fire is well executed the enemy’s assault is “killed in the egg” as the French expression has it.
Liaison in the Sector.
(a) Telephone: There are two different systems of telephones.
First, there is the system connecting the infantry command posts, support points, centers of resistance, sector, and division headquarters, with the command posts of the artillery protecting the different infantry areas. These are direct lines between the command posts and the groups of support artillery. Also, this system connects the command post with observatories, depots, medical aid stations, kitchens, etc.
Secondly, there is the system connecting the chief of artillery with his subordinate commanders, the artillery observation posts, and the artillery dumps. In this same system the artillery command posts are again connected with the infantry units which they are to support. Special lines are run by the artillery to the officer and N. C. O. of the artillery attachment of liaison in the infantry areas.
_Telephone Liaison._
Consequently, the liaison between the artillery and the infantry is doubly provided for in these two systems.
The lines of connection between the infantry and the artillery must be separate from those within the infantry area and those between the artillery commander and his subordinate units.
Confidential information should never be telephoned except in cipher. Conventional designations are employed to call the different posts. Strict regulations are maintained as to who should use the telephone and for what purposes.
The weak point of a telephone system is that it is often broken by bombardment or earth-slides. This can be partially remedied by constructing as few direct lines as possible, by burying the wires in the bottom of the boyaux, and by executing repairs as quickly as possible.
(b) Wireless and Ground Telegraphy: The battalions in the first line have ground telegraph apparatus connecting them with the regimental headquarters, and these, in turn,can communicate with the general headquarters by wireless. This means of communication is only employed when the telephone cannot be used.
(c) Signalling: It is difficult to establish signal communication within the sector without being seen by the enemy. However, at night with flashlights it is possible, especially in hilly country, to communicate from front to rear within the position. The receiving post should be able to certify received messages. When practicable, communications should be established between the command post of the center of resistance and the sector command posts, and from the latter post to the artillery. This method of liaison is organized as a duplicating means or as a temporary substitute for the telephone.
(d) Rockets: Signal rockets are used to communicate with the rear. Different forms and colors of rockets are used to signify different things. As we have seen, the most important use of the rocket is to signal for barrage fire. It is often necessary to relay a rocket signal from a second position in the rear to make absolutely sure that it reaches the artillery support.
Signal rockets are also used to communicatewith aëroplanes, but this means is usually only employed during an attack.
(e) Runners: The liaison established with runners is best of all, from the point of view that it usually never fails. During heavy shelling it is the only sure means of communication.
_Example of a Chain of Runners._
The ordinary messengers or orderlies are not used as runners. A chain of trained runners is used, located in a little post, shelters, or shell holes; Each post contains three runners, their distance being from 150 to 300 yards apart. Each runner is selected from the unit located near the next post in the chain,that is, the one to which he is to run. Often the divisional cavalry furnish these runners.
The chain of runners is under the command of a N. C. O. who is responsible for its efficiency. He has an important task on his hands. He must assure himself that every runner knows, not only his two neighboring posts, but also the general direction of the chain. He must change disabled runners and fill gaps in his chain. It becomes his duty to instill into the runners the importance of their duty.
(f) Carrier Pigeons: Carrier pigeons are the last means of communication. They have been found to give excellent service during heavy shelling or gas attacks. They do not fly very easily at night.
Each command post of a center of resistance in the first line has a pigeon post. These consist of two reliefs of men, four pigeons, and the necessary equipment and food. The pigeons themselves have to be relieved every few days. The care given to the birds at the command posts must not be as good as that at the dovecot in the rear, so that when they are released they will return immediately to the latter place, from where the message is delivered to its proper destination.