SECRET AND CONFIDENTIAL FOR OFFICIAL USE ONLY NOT TO BE TAKEN INTO FRONTLINE TRENCHES NOTES ON RECENT OPERATIONS, NO. 3 ARMY WAR COLLEGE AUGUST, 1917 WASHINGTON GOVERNMENT PRINTING OFFICE 1917 War Department Document No. 655 Office of The Adjutant General. WAR DEPARTMENT, Washington, August 23, 1917. The following Notes on Recent Operations, No. 3, are published for the information of all concerned. (062.22 A. G. O.) By order of the Secretary of War : H. L. SCOTT, Major General, Chief of Staff. Official : H. P. McCAIN, The Adjutant General. (3) 667613 War Department, The Adjutant General'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 in your personal possession and are not to be copied, nor are any parts of their contents to be communi- cated either directly or indirectly to the press, nor to any per- sons not in the military or naval service of the United States. In Europe 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 document! may come. By order of the Secretary of War : H. P. McCain, The Adjutant General. (4) TABLE OF CONTENTS. Page. German smoke-producing apparatus 7 The organization of an infantry battalion and the normal for- mation for the attack • 11 Tanks.... 27 Notes on mining 33 Machine guns, order of the Sixth Bavarian Division regarding . 59 Methods of attack of the German Infantry 61 The construction of field defences. 65 Instructions for mine warfare 71 The principles of trench warfare 77 Memorandum and letter to pilots and observers, Second Bri- gade Royal Flying Corps 91 Hints on reconnaissance for mines and land mines in the area evacuated by the Germans 95 Directions for the use of antigas horse respirator 105 Patrol and control of "no man's land" 109 The employment and duties of artillery aeroplanes in posi- tion warfare 125 Part 6: Communication between infantry and aeroplanes or captive balloons 144 Hints for trench mortar officers 157 Preliminary notes on recent operations on the front of the second army observation stations 161 Notes on communications during recent operations on the front of the second army 177 Notes on the use of smoke 181 Notes on screens 189 Instructions for the demolition of hostile guns with 3-inch Stokes trench mortar bombs and special slow fuse 195 Employment of 3-inch Stokes mortars in recent fighting 197 Principles of command in the defensive battle in position warfare 199 Consolidation of trenches. Localities and craters after assault and capture, with a note on rapid wiring 205 German instructions for the employment of flame projectors . . . 243 (5) GERMAN SMOKE-PRODUCING APPARATUS. Description. — The Germans use smoke-producing apparatus based on the reaction of a mixture of anhydride and sulphuric chlorydrine (in equal parts) on quicklime, which produces a cloud of heavy white smoke. There are three types of apparatus : Name. Approximate di- mensions. Total weight. Weight of lime. Height. Diameter. Meter. Meter. Kilos. Kilos. 0.74 .91 0.49 .38 95 69 28.6 17.7 .4 .35 54 10.9 Quantity of acid. Nebel-trommel"N. T. "(smoke drum) Nebel-topf "N. L." (smoke pot). Nebel-kasten "N. K." (smoke box) Liters. 21.3 12.2 Each generator comprises an iron container (drum-shaped or spherical) filled with a mixture of anhydride and sulphuric chlorydrine, held by pivots on the inside or over the iron drum that contains the lumps of quicklime. Method of use. — To use the generator, take off the lid of the drum holding the quicklime and draw out the screw stopper from the container holding the acid. The latter is then turned to 180° by means of a crank. The liquid falls drop by drop on a wire gauze, drips onto the lime, and the heat of the reaction volatilizes the smoky product. In the " N. T." or " N. L." genera- tors the smoke escapes through the holes in the lid. To put the apparatus in use place it in a hole in the ground, protecting it from shells. A small earth embankment should be thrown up in front of the generator. Effect. — According to a German document, the smoke is not poisonous, and there is no danger in passing through it. It may cause a slight irritation to the throat and face, but it is abso- lutely harmless. The mixture of anhydride and sulphuric chlo- rydrine is noninflammable. (7) 9 An " N. L." and an " N. K." generator were tested on a day when the velocity of the wind was 13 kilometers per hour. The following results were obtained : The " N. L. " generator produced a very large and very opaque cloud of white smoke, which traveled more than 3.5 kilometers. The emissions of smoke were reduced to a quarter of their origi- nal volume at the end of 4 minutes, and disappeared practically entirely at the end of 8£ minutes. " N. K." generator. — A smaller cloud was less rapidly formed than in the preceding case. It lost about one-half its original volume at the end of 4 minutes, but continued for 10 minutes. The " N. T." generator is said to be twice as effective as the " N. L." generator. Use. — The German documents say that this apparatus per- mits defensive and offensive barrages to be made of smoke. Near the front operations can be masked. Works in the rear can be temporarily hidden from aircraft. THE ORGANIZATION OF AN INFANTRY BAT- TALION AND THE NORMAL FORMATION FOR THE ATTACK. (Issued by the General Staff, April, 1917.) PART I. ORGANIZATION OF AN INFANTRY BATTALION. (Extracts from O.B/1919, d/-7.2.17, issued by G.H.Q., British Armies in Frauce.) 1. Necessity of uniformity of organization. — In order to insure the necessary degree of uniformity of training and tactical method throughout the army, it is necessary that there should be similarity of organization in all battalions. The following instructions are therefore issued. 2. Battalion. — The battalion will continue to consist of — (a) Battalion headquarters; (&) 4 companies, consisting of 4 platoons of 4 sections each. 3. Battalion headquarters. — In addition to the personnel shown in war establishments as forming part of the battalion headquarters, certain other personnel will be attached. This personnel, which is principally employed on administrative du- ties, will be temporarily detached from companies whilst so em- ployed, but will remain on the establishment of the companies for accounting purposes. A headquarters company as such will not be formed. The detail of the personnel included in the bat- talion headquarters is given in Appendix I. The total should not exceed 150 other ranks. The personnel composing the battalion headquarters can con- veniently be divided into two categories, namely, the fighting portion and the administrative portion. The former will be grouped into sections, each under a commander. The strength of the latter will not exceed 80 other ranks. (11) 12 4. Companies.— Each company will consist of — (a) Company headquarters and (6) 4 platoons. Company headquarters, the strength of which should not ex- ceed 14 other ranks, will be composed entirely of fighting troops. and will be formed as a section under a commander. 5. Platoons. — The organization of a platoon is given in S.S. 143. 6. The organization outlined above is designed to create b fighting machine composed solely of fighting ranks and distinct from the necessary administrative establishment. 7. The essence of this organization is — (a) That the platoon should constitute- a unit for fighting and training, and should consist of a homogeneous combination of all the weapons with which the infantry is now armed ; {by That specialists should all be with their platoons and companies, except such as may be required at bat- talion and company headquarters either for pur- poses of fighting or for instructional duties; (a) That every portion of the battalion, including the fighting portion of battalion headquarters and com- pany headquarters, should consist of ;i certain Dum- ber of permanently formed units, namely sections. each under its own commander; (d) * * * * * (e) That every man is available for working and carrying ptrties, irrespective of the weapon with which he is armed ; (/) That one Lewis uun with its detachment is allotted to each platoon. Although this will he the normal organization, it may often he advisable in dealing with particular tactical situations to allot a second Lewis gun to a platoon, or to withdraw temporarily one. two, or more of those guns from platoons for special tactical employment under the orders of Company or battalion commanders. It is to be clearly understood that the normal organization is not to interfere with any such temporary Special grouping or employment as circumstance may render desirable. 13 Note. — Paragraph 5, page 17, of S. S. 135, " Instructions for the training of divisions for offensive action," will be amended accordingly. 8. In order to meet the varying conditions under which bat- talions serve, to allow of more flexibility as regards the number of men detached for extra regimental employ, and to meet the case of heavy battle casualties, a maximum and a minimum strength of 28 and 44 O.K., respectively, have been laid down for the platoon in S.S. 143, PART II. THE NORMAL FORMATION FOR THE ATTACK, I. General principles of the formation. — In the special circum- stances of present warfare it has become necessary to modify the provisions of section 114, Chapter IX, " Infantry training " in so far as the attack is concerned, and it is advantageous, under existing conditions, to lay down a normal formation for the attack. The normal formation described below is one which has fre- quently been employed with success in recent fighting; it is simple and adaptable to the varying conditions of trench-to- trench attack. It should also prove suitable to most conditions of open warfare. So far as the platoon is concerned, the formation described should be applicable to most circumstances and it should seldom be necessary to depart therefrom, while as regards the battalion it aims at elasticity. The platoon is to be regarded as the unit in the assault. The frontage of an infantry battalion in the trench-to-trench attack may range from 200 yards, against a highly organized position, to 600 yards or more, against one less highly consolidated. II. Application of weapons. — The weapons now under the hand of a platoon commander should be arranged according to their various peculiarities. That is to say. the rifle and bayonet and the bomb, being the most effective offensive weapons, should be placed as far forward as possible, closely supported by the rifle grenade, which may be regarded as the " howitzer " of the platoon, and by the Lewis gun, which is the weapon of oppor- tunity. 14 Each platoon will therefore normally be disposed in two lines. bombers end riflemen in the front line, rifle bombers and thf* Lewis gun 1 in the second line. These two lines will constitute one wave irrespective of " Moppers-up." (See PI. "A." I Further, It has been found convenient as a general rule for the company to be formed on a two-platoon frontage. The platoon, therefore, should normally be formed in two lines, constituting one wave, and the company in two waves. (See PI. "B.") In this connection it can not be too often urged, firstly, that in the assault every man is a bayonet man, excepting No. 1 of the Lewis gun; secondly, that every man is a bomber; and thirdly, that every man in rifle sections is also trained to be either a Lewis gunner or a rifle bomber, with a view to replac- ing casualties in men armed with those weapons. III. Jiitcrrals and distances. — Intervals between men should usually be 4 to 5 yards. The distance between lines should be 15 to 25 yards and that between waves 50 to 100 yards; to avoid the rear waves being caught in the enemy's barrage, these distances may be reduced to meet the requirements of the moment. Rear waves should move in sections in artillery fori nation. IV. Moppers-up. — "Moppers-up V should follow the second line of a wave. (See Pis. "A," " B," "C," " D," ami "E.") It is considered preferable to find them, when possible, from the platoons and companies whose objectives they are to clear. If, however, the numbers required for clearing these objectives are so great as to deplete unduly the platoons or companies to which they are allotted, moppers-up must be found from another company or possibly another battalion. This case will usually occur when attacking a highly organized position at the com- mencement of an offensive. V. Allotment of objectives. — Each wave must be allotted a definite objective, and each component part of each line should .have-a definite duty to perform according to the weapon with which it is armed. Thus, in the irench-to-trench attack, if the l>l:iixtitutc Ap- pendices I (A), I (B),I (C) and II as follows: Appendix I (A). BATTALION HEADQUARTERS. Fighting portion. Fighting portion — Continued. Officers : Commanding offi- cer Second in com- mand Adjutant Lewis gun officer. Officers : Signalling officer __ 1 Bombing officer 1 6 Other ranks : Sergeant major 1 Orderly room clerk. _ 1 17 Fighting portion — Continued. Fighting portion — Continued ( >ther ranks — Continued. Gas . Signalers Stretcher bearers__ Runners Fioneers Cooks Batmen 2 IB 4 9 11 o 6 49 Balance to be made up by additional stretcher bear- ers, runners, police, or scouts, at the discretion of battalion command- ers : Total A dministrati re portion . ( )fficers : Assistant adjutant Quartermaster Transport officer 21 70 Other ranks : Quartermaster ser- geant and storemen_ Company quartermas- ter sergeant and storemen Transport establish- ment and groom s__ Shoemakers Tailors Butchers = Postman Cooks Batmen TO Balance to he made up by additional shoeniakers, tailors, cooks, transport establishment, police, san- itary men, or watermen, at the discretion of bat- talion commanders 10 Total 80 Appendix I (B). COMPANY HEADQUARTERS. Company sergeant major 1 Signalers 4 Runners (including 1 batman) 4 Batman or cook 1 10 Balance to be made up by additional stretcher bearers, run- ners, or scouts, at the discretion of company commanders. 4 Total 14 9784°— 17 2 18 Appendix I (C). PLATOON HEADQUARTERS. Platoon sergeant 1 Signaler 1 Runner I Batman 1 3 Total -1 Note to Appendices I (A) -I (C). — These numbers do not include those mentioned in S. S. 135, p. 58, " Numbers to be left behind when the battalion takes part in the attack," as it should always be possible to replace those left behind by an equivalent number of men withdrawn from classes, extra regimental employ, etc. Appendix II. NUMBERS TO BE LEFT BEHIND WHEN THE BATTALION TAKES PART IN THE ATTACK. In each battalion : Per battalion. Company sergeant majors 2 33 per cent signalers : Mo 33 per cent runners J 1 -"> (las instructor ] Bombing instructor 1 Lewis gun instructors 2 Any other instructors in special work, such as dugouts 8 Total 32 82 In each company : Sergeant 1 Corporal 1 Lance corporal 1 Total 3 12 In each platoon : Rifle bomber 1 Scout and sniper 1 Lewis gunners 2 Total 4 64 Grand total 108 »If up to full strength. m Other ranks. Establishment of a battalion, including attached. 971 1 Fighting. Admin- istrative and em- ployed. Fighting. Admin- istrative and em- ployed. Battalion headquarters: 70 70 80 80 4 company headquarters of 14 each 16 platoons: Of 44 each .. 16 704 56 Of 28 each... 448 Sick and extra regimental employ and 61 317 830 141 574 397 971 971 The above figures include those who must be left behind when the battalion takes part in an attack. (See S.S. 135, p. 58.) 20 Platk "A." THE PLATOON. Taking: an average strength of 36 other ranks and headquarters at 4 other ranks. (Showing 2 platoons in 2 waves, with the right the outer flank.) < tOO' > qdddIdodo i ooooSoooo Jat Un * / aaaaiiaaaa 2nd Line' 1 I nt WAVE 3rd Lint (Moppers-vpfor Iht Objtctivt allotted to the 2nd Wave). DODDBQDOO 0000180000 4th Line 3 6 + *4:a*444Daaaa!aaaa 6th Line, KEY. £ Platoon commander. (^ Platoon sergeunt. jfc Section commander. O Rifleman. O T.c.vis gunner. O Pomber. 9 Rifle bomber. A Mopper up. » Platoon H. Q. 2nd WAVE 21 NOTES. Two platoons are depicted showing the different positions of leaders in first and second waves. The platoon is the unit in the assault, moves in one wave of two lines, and has one definite objective. Elvery man is a rifleman and a bomber, and in the assault, with the exception of the No. 1 of Lewis gun, fixes his bayonet. Men in rifle sec- tions must be trained either to the Lewis gun or rifle grenade. Bombing and Lewis gun sections are on the outer flank of platoons. In assembly the distances between lines and waves may conveniently be reduced to lessen the danger of rear waves being caught in the enemy's barrage ; the distances will be increased when the advance takes place. " Moppers up " follow the second line of a wave and precede the unit for which they are to mop up. See plates " C " and " D." If the num- bers are large, they must be found from a different company or bat- talion. Small numbers are preferably found from the unit for which they are to mop up. They must wear a distinctive badge and have their own commander. 22 THE COMPANY. Plate " B. Taking 4 platoons at an average strength of 36 other rank each, and company headquarters at 14 other rank. 200" /5\o25 l I 1st WAVE A A A ▲ A A A ▲ ▲ 3rd Line (Moppen-vp ),., " tloe all* Woe*) 50* too* \ '5% 25* 1 | 4 th Line 6th Line K 2rd WAVE KEY. W Company commander. r^M Company headquarters. V Platoon (in two lines). /A. Moppers up. NOTES. Thf company moves in two waves, has two objectives, and is dis- tributed in depth. " Moppers-up " follow the second line of a wave and precede the unit for which they are to mop up. (See Pis. C and D.) If the number* are large they must be found from a different company or battalion. Small numbers are preferably found from the unit for which they are to mop up. They must wear a distinctive badge and have their own commander. 23 H 2 M it 2* III <^ a a a © o M "5 o^ © S-S-S- S-S-S- © o © 5^5= .5 -S-S-S ,2 «N 93rJ.lo J 2 < £ H H •4) > Oi > c £ ?3 t? -*-> a r olr > £©?S •-> £.q o - I o 2 il & s *ojJ ♦to -. — V- ^* - — ^5*| 24 KB*. Battalion Headquarters. Company commander. Company headquarters. Platoon. Moppers up. The battalion- moves in four waves, each direct to its objective, and is distributed in depth on attaining them. " Moppers up " follow the second line of a wave and precede the unit for which they are to mop up. (See plates "C" and " D.") If the numbers are large they must be found from a different company or bat* talion. Small numbers are preferably found from the unit for which they are to mop up. They must wear a distinctive badge and have their own commander. In this instance the organization of " moppers up " is complicated. It may be advisable to detail a company from another unit as a re- serve to the battalion. This formation is capable of easy modification to deal with three objectives. Battalion headquarters does not move in a trench-to-trench attack until a report is received that the objective has been captured, i S 135. " Instructions for the Training of Divisicns for Offensive Action," Sec. XIII, par. 3.) 25 Plate " P." THE BATTALION. Taking 16 average platoons of 36, 4 company headquarters of 14, and battalion headquarters of 70 other ranks. fBt Battalion headquarters. o Company commander. CSi Company headquarters. ^ Platoon. A Moppers up. Four objectives : First wave to second objective. Second wave to first objective. Third wave to fourth objective* Fourth wave to third objective, i. e. — Leap frog. I ' I I ' I I ' I I | I 4 * » »*» » * A ' - O&Coy. C6 Coy. LA Ei I'll II I I I I I . I I NOTES. 1st Line \ 1st WAVE 2nd Line. \ to 2nd Objective 3rd L{ne. Moppers-up for 1st Objective. 4th Line. ~\ 2 nd WAVE 5th line. $ tout Objective. [3rd WAVE [to 4th Objective. Hoppers-* p for 3rd Objective. 4th WAVE to 3rd Objective. The battalion moves in four waves, the first two waves to the nearest objectives and the last two waves passing through to the two farthest objectives, and is distributed in depth on attaining them. " Moppers up " follow the second line of a wave and precede the unit for which they are to mop up. (See plates " C " and " D.") If the numbers are large, they must be found from a different company or battalion. Small numbers are preferably found from the unit for which they are to mop up. They must wear a distincitve badge and have their own commander. In this case the organization of the " Moppers up *' is simple. It is not usually necessary to detail a reserve from another unit, be- cause the first and second waves can reform after the third and fourth have passed through them. This formation is capable of easy modification to deal with three objectives. Battalion headquarters does not move in a trench-to-trench attack until a report is received that the objective has been captured. (See S.S. 135, " Instructions for the Training of Divisions for Offensive Action," Sec. XIII, par. 3.) 26 p I T3 •= C © «< 8.S H ^ ' H t! « H * « e a o w ^ (1 **oi ; -»oH NOTES ON THE USE OF TANKS AND ON THE GENERAL PRINCIPLES OF THEIR EMPLOY- MENT AS AN ADJUNCT TO THE INFANTRY ATTACK. (Issued with special reference to the " Mark IV," 1917, pattern.) 1. With tanks, as with any other arm, satisfactory results can only be obtained by the close cooperation of all arms. Although the employment of tanks as an adjunct to offensive operations is still to a great extent in an experimental stage, it is neces- sary for all commanders and subordinate leaders of all arms to realize the limitations and capabilities of tanks, and to know the general principles of their employment, so far as these prin- ciples can be laid down at present. This is all the more neces- sary as occasions will inevitably arise (as the number of tanks in this country increases) when troops will be required to oper- ate with tanks without any previous experience or training. 2. (a) The radius of action of the Mark IV tank and the limit of endurance of its crew is not more than about eight hours, this period being reckoned from the time of departure from and return to a position where the crew can rest and where the tank can be overhauled and refilled. Its pace varies from one-half mile to 4 miles per hour, accord- ing to the nature and state of the ground. For purposes of calculation its average pace, when fighting under favorable con- ditions, may be taken at about 2 miles per hour. (b) The Mark IV tank can cross trenches 9 to 10 feet wide, can surmount a perpendicular obstacle 4 feet high, and move up or down a slope of 1 in 2. So long as the bottom is hard, mud or water to a depth of 2 feet or so is no bar to its progress ; but, owing to its weight, ground that has been very heavily shelled or is very sodden to a considerable depth is unfavorable to its employment. (c) Wire entanglements do not form any obstacle to tanks, but the passage of a single tank will only, as a rule, flatten two passages 2 feet wide through the wire. The passage by infantry in single file may therefore be made easier, but the wire remains more or less an obstacle. (27) 28 Tanks can pass easily through thick hedges or thick woods composed of small trees, but large stumps of broken tree difficult to see and form a serious obstacle to tanks. In villages they can operate with success so long as the streets are recognizable, but when the village is reduced to heaps of rubble, tanks are liable to. get ditched in the cellars. (d) Although the Mark IV tank has an Improved silencer, it can still be heard when in movement within 250 yards unless the noise is covered by a certain amount of machine-gun or artillery fire. The approach of a tank to its final position pre- paratory to attack should always, therefore, be covered by a certain amount of shooting. 3. Against infantry or machine guns tanks are almost invul- nerable (the Mark IV tank is practically proof against the Ger- man armor-piercing bullet) and have great moral effect as well as considerable fire power, but the effect that each tank exer- cises is purely local. On the other hand, when stationary they form an easy target for the enemy's artillery, though bard to hit effectively when in motion. In addition, they are easily put out of action by a hostile antitank gun. It follows, therefore, that — (i) It is essential that the action of the artillery and the em- ployment of tanks should be carefully coordinated. Tank- always draw hostile artillery fire, and counter-battery work is therefore of particular importance. (ii) An artillery barrage will usually be necessary both to assist tanks in overcoming stationary antitank armament and to cover the advance of the infantry in the usual way. (iii) Tanks should keep constantly in motion unless they are covered from hostile artillery fire, e. g., by the configuration of the ground or being amongst the enemy's troops. 4. The power of tanks is considerably limited by poor vision. which makes it difficult to recognize objectives or to follow com- plicated routes. As a general rule, therefore, the most suitable objective for tanks is a clearly defined line of trenches. In any case the objectives assigned should be visible and obvious, and the task simple, definite, and limited. In detailing tanks to objectives, it should he borne in mind that— (i) As far as possible, the general direction of their advance should be parallel to that of the infantry. .Movements of tanks 29 diagonal to that of the infantry have been found to draw the latter off their objective or line of advance. (ii) The best moral effect is obtained, where conditions are suitable, from the employment of large numbers of tanks attack- ing several objectives simultaneously. On the other hand, to provide for emergencies, and to replace tanks which from one cause or another have been unable to reach their objective, a proportion of tanks should be kept in reserve. These conflicting requirements must be carefully balanced ac- cording to the circumstances of each case. (iii) As a general rule, it is useless to give tanks the task of finding objectives, such as detailing a single tank to look for a machine gun which has not been located. If machine guns have been accurately located, tanks are most useful to overcome them. (iv) The fewer the tanks employed on a given front the easier it will be for the enemy to concentrate his guns on the tanks, and the greater will be the proportion of tanks knocked out. Also, owing to accidents of ground or mechanical trouble, it is not safe to rely on all tanks reaching their objectives. For these reasons it will seldom be advisable to detail less than a section of tanks for any one objective. (v) Tanks can force their way into almost any objective, but can not halt to hold them in the open, where they are exposed to direct hits by hostile artillery. The position gained must be taken over by the infantry. When this has been done, tanks should move on to another objective or to the rallying point. If the infantry are not able to reach the tanks, it will seldom be any use for the tanks to continue their advance. 5. The frontage to be covered by tanks is governed by the par- ticular situation of objectives and by the facilities of approach. They should not normally work less than 100 yards apart. Very careful previous reconnaissance is essential in order that tanks should not be deliberately committed to an impracticable route. A plentiful supply of aeroplane photographs must be sup- plied to the tanks for this purpose. In addition, the routes to the starting point require very de- tailed examination in order to insure tanks arriving in time. 6. It should seldom be necessary to employ tanks at the com- mencement of an offensive to assist the infantry assault on a 30 hostile front system of trenches which can be adequately dealt with and destroyed by our own artillery bombardment As the appearance of tanks will immediately bring down a hostile artillery barrage, they should not usually precede or even start with infantry at the commencement of an attack. Normally, tanks should wait concealed at first and go out later : (i) To deal with pockets of the enemy and strong points hold- ing out in the objectives captured. (ii) To deal with defenses beyond the hostile front system which are interfering with the progress of the battle by holding up the advance of the leading troops. (iii) When the infantry has reached the farthest objective, and there is sufficient space beyond, to work with infantry patrols and advanced guards and help them to deal with ma- chine guns. They may also be employed for special tasks, such as — (iv) Covering the formation of a defensive flank by working outward, so as to provide more room for consolidation. (v) Flattening sunken or concealed wire which can not be cut by artillery fire. The chances of success are not great and their use for such an abnormal purpose should be rare. The role of tanks stated above will usually entail their pass- ing through the hostile barrage. This can be affected without undue loss, so long as the tanks keep moving. 7. From the foregoing the general principles of the employ- ment of tanks may be summarized as follows j (i) Each tank formation should be disposed in depth so that if the leading tanks become casualties others c:m move up to carry out the task. (ii) The tanks should follow the infantry immediately after the first assault with a view to— (a) Assisting Hie Infantry to mop up pockets of the enemy. (b) To push on to special objectives or carry out suitable tasks which will usually be found in and beyond the second ob- jective of the main infantry attack. (iii) The tnsks and role of the tanks should be worked out by the Commanders concerned in the same way and in coordina- tion with the artillery program, and each tank attack should be supported by mopping-up parties and sufficient infantry to con- solidate and hold the objectives when gained. 31 8. Both for the reason that a tank draws fire and on account of its liability to lose direction, infantry should not as a rule immediately follow tanks (except for the purpose of passing through wire entanglements), and any tendency to bunch behind the tank should be checked. From the limited experience available, it would appear at present that the most suitable formation for the infantry to adopt is to follow tanks in small groups in the intervals between •the tanks. The advance of the infantry to the objective being controlled in the ordinary manner, independent of any devia- tion of route taken by the tanks. 9. For purposes of administration, tanks are general head- quarters troops, and will be allotted in brigades to armies for certain operations. The army will allot tanks in brigades or battalions to the corps in accordance with the general plan. The tank units so allotted become, for purposes of the battle, corps troops, and their objectives will be decided by the corps. The details of the movements of tanks to gain these objectives will be worked out in conjunction with the division under whose orders they are placed for the specific operation. 10. The signal arrangements of the heavy branch, machine- gun corps, are not yet completely organized, but are being framed with a view to providing communication between — The O. C. tank brigade and the army or corps commander. The O. C. tank battalion and the corps or divisional com- mander. The O. C. tank company and the divisional or brigade com- mander under whose orders he is operating. The O. C. tank section and the infantry commander on the spot. The fighting tanks and the forward troops (and by pigeons to the commander of the operations). NOTES ON MINING. (From the French.) CONTENTS. Page. I. — General '__.: 33 II. — General principles of the employment of mining •__. 34 ill. — Attack : 37 Execution of the attack 39 IV. — Defence ___. 41 APPENDICES. I. — Arrangement of a mine system _._. 43 Role of the different parts of the system____ , 43 Mine dugouts , „ 44 Entrances to mines 44 II. — Execution of the work : Documents 45 Organization of work- __: _ 45 Types and construction of galleries- 46 III. — The underground struggle : Lookout for the enemy 47 Effects of mines-, ! 48 Destruction of hostile galleries '. '. 48 Continuation of work after an explosion 50 Unexpected meeting with the enemy 50 Danger of isolated attacks. Necessity for protection of flanks :___ \ __-__ 51 Mining in cooperation with a general offensive — 52 IV.— Methods of the GermanS-___ 53 Methods of attack 54 Types of galleries and tools_ , 57 I. GENERAL. l. As soon as the opposing forces became stationary, mine warfare was inevitable. With the enemy entrenched only a few dozen yards away, the idea naturally occurred that his works might be .destroyed from below and that by mining not. only could casualties be inflicted, but a very serious moral impression caused. l - 9784°— 17 3 (33) 34 At first the operations were very elementary. A single gallery or Russian sap was driven to the point desired, a salient in the enemy's trench, a listening post, etc., so that a charge — it was always a small one — could be laid there. The enemy soon became aware of our proceedings and was on the alert underground ; to our mine attacks he replied by mining. Thence onward systems of mining and countermining were gradually developed, absorbing a considerable number of men and large quantities of explosives. 1 2. The attacks are sometimes undertaken only to demolish a portion of a hostile trench, sometimes in view of a local operation ; sometimes they form part of a large offensive movement. Gen- erally speaking, the results hitherto obtained have not been pro- portionate to the efforts expended on them. There is no reason, however, to conclude that mining should be abandoned. A study of the facts shows that where an under- ground attack has been properly used it has been of great serv- ice, but that when attacks have been without result they have almost invariably been so because they were conducted under unfavorable conditions which from the first made their su* doubtful. Mining is an effective weapon, but it must be applied to suit- able objectives and its use restricted by certain rules which have been deduced from experience. II. GENERAL PRINCIPLES OF THE EMPLOYMENT OF MINING. 3. Prior to this war mining was only thought of in connection with siege warfare. Works which could not be destroyed by gun- fire were attacked by mining. The besieged replied by counter- mining. But in the underground struggle thus initiated the besieger with superior personnel, material, and explosives at his disposal was bound in the end to win. Each of his successes meant a 1 The state of our front lines, which* continually suffer from hostile artillery and trench mortar fire, now necessitates greater activity on our part than in the past. The engineers, in almost all the sectors, are completely absorbed in the mining struggle. The number of men already drown from infantry to assist them is no longer sufficient. (Extract from an order of the German VIII Reserve Corps toward the end of 1915.) 35 grave setback to the. besieged — the loss of an important work or of a valuable piece of ground. In siege warfare the factors which gave mining its special character were: (i) The objectives were important and clearly defined. , (ii) Every inch of ground gained was of value. (iii) The means at the disposal of the besieger insured su- periority. It is otherwise in this war : (i) The enemy's works do not offer objectives of vital im- portance. (ii) The loss of a few yards of ground does not matter; the line can easily be reestablished in rear. (iii) Tlie two sides have equal resources. 4. Under these conditions, what henceforth will be the r61e of mining? It may be said at once that when the objectives in the zone of possible operations are not sufficiently important to warrant mining operations on a large scale for the sole purpose of destroying them, mining offensives should always be associated with more or less extensive operations above ground. The objectives will naturally be such points as can not properly be engaged by artillery: Flanking positions on which a suffi- ciently accurate fire can not be brought to bear; strong points in the enemy's first line which can not be completely destroyed by shells alone, such as villages, areas organized with very deep dugouts, etc. It is only by careful study of the defensive value of different points in the enemy's line of defense which it is proposed to attack, and of the possibilities of an attack on each of these points, that a decision can be arrived at as to where the em- ployment of mining will be of value. 5. There are, however, other considerations which affect the choice of objectives. The chances of a successful mining attack vary with: (a) The nature of the ground, which will in varying degrees — (i) Present difficulties to the construction of galleries (rocky ground or wet soil). (ii) Favor rapid progress, by the suitability of ground for mining (strata easy to work). Rapidity of execution is, in mining as in every operation of war, one of the elements of sue- 36 (iii) Allow of an attack in force (a considerable depth of suitable ground where galleries can be made at different levels. which is of great value should the enemy be met with). Underground fighting is not the object aimed at; but if the enemy is met, and this must always be reckoned with, be must be engaged under the most favorable conditions, defeated, and passed. (iv) Enable progress to be made without attracting the at- tention of the enemy (ground where it is not easy to listen, or where the work can be carried on at deep levels). (o) The contour of the ground, which will in varying de- grees give facilities for — (i) Gaining a good depth (the conditions are obviously better if the gallery can be started on the side of a hill rather than the side of a valley). (ii) Removing the spoil and hiding it (the proximity of the mine head to defiladed approaches, woods, etc., is an advan- tage in this respect). (c) The probability of reaching the objective without attract- ing the enemy's attention. It is better not to encounter the enemy en route. If it becomes absolutely necessary to fight him underground, it is quite sible, even though he is worsted, that his opposition may 80 in terfere with our plans as to deprive us of the power to fire the mines when desired. For this reason, other things being equal, ground where min- ing has as yet not been carried on is preferable to plaros where mine fighting is already in progress, and where the enemy, in consequence, is on the alert. 1 (d) The distance which separates the opposing li The difficulties of mining (removal of soil, ventilation, etc.) increase very rapidly as the distance of the working face from the mouth of the shaft lengthens. For this reason the rang attacks has, until this campaign, rarely exceeded 100 to 150 yards. This limitation of range had lew drawbacks in siege warfare. In this war, on the contrary, the production of explosions Ins the enemy's linos has a very definite effect. It is there, now that the enemy has reduced the number of troops in his front 1 Sop the example of ( 'iirency. May. 1015 (par. 49). 37 line, that the best results will be obtained ; and there also the moral effects of the explosion will be greatest. Although there are attendant difficulties, it is not impossible to attain distances which considerably exceed those which hith- erto have been regarded as the maxima. It must, however, be clearly understood that long tunneling operations should be undertaken only when the objective is of special importance and when the conditions are very favorable. Lastly, the large amount of personnel and material required for each attack must naturally limit the total number of attacks that can be undertaken. 6. To sum up, the decision as to which parts of the fronts shall be the objectives of mining attacks must be based on the follow- ing considerations : (a) Which places in the enemy's lines it is specially impor- tant to attack by mining on account of their nature and of the difficulties which would be experienced in attacking them above ground in the ordinary manner. (b) Which of these places (after a technical study of the nature and contour of the ground has been carried out) offers the best chance of success to a mining attack. 7. It is quite evident, of course, that all the conditions con- sidered favorable to mining will only very rarely be present together, and it will therefore be necessary to select those places which combine most, and to exploit these to the fullest extent. As mining is a slow process, it can only be employed in the first phase of a combined offensive for the capture of the enemy's front system. Nevertheless, where the ground is suitable, bored mines can bo used to advantage for the attack of certain parts of the enemy's second positions where the obstacles can not be reached by our artillery fire. Applied by "batteries" on certain parts of the front, they would produce, simultaneously, gaps in the wire entanglements, and defiladed commiinications by means of which the enemy's position can be reached. III. ATTACK. i 8. Project of attack.— The commander, after having indicated the objectives, will order a scheme of attack to be drawn up by the engineer officers who will be in charge of the work. This, when approved by him, will be the working plan. 38 It is absolutely necessary to have a scheme of attack. Numer- ous attacks have failed on account of there being no clearly thought-out plan. The commonest mistake (at least in the early days of mining) has been failure to anticipate possible counter-mining by the enemy, and to commence the attack with- out guarding against it. 9. The project of attack will include — ( i ) The plan of the work to be carried out. (ii) List of personnel, material, and tools required. (iii) The method of carrying out the work (order of urgency of the work and the allotment of the means available). It will be based on — ( i ) A detailed study of the objective and the ground. (ii) Knowledge of the properties of the means available < what can be effected with the tools and the power of the explosives). (iii) A consideration of the principles which govern every operation in war (concentration on the points of attack of all means available which can usefully be employed, the taking of every precaution to insure that the objective will be reached in spite of the resistance of the enemy, etc.). 10. From a study of the objective on the map and from aero- plane photographs, supplemented by actual observation on the ground, the following points can be settled: (i) The limits of the front to be attacked in order to cooperate in the combined offensive. (ii) The exact objectives to be attacked. (iii) The possibility of countermining by the enemy. From a study of the subsoil (borings being made if necessary ) the undermentioned facts can be established : (i) The limits in depth of the strata in which mining is pos- sible, and in which consequently it is necessary t<> take precau- tions. It must be noted that the enemy, when warned, may take the counter-offensive and establish a system of counter-mines. not only against our attacks but also against neighboring por- tions of our systems which offer suitable objectives within rea- sonable distance. This has happened on several occasions. (ii) The strata in which work can be carried on with the greatest rapidity or security. 11. Study of the objective and the ground will, therefore, fur- nish the information necessary to settle the essential elements of the scheme; that is to say, the preparatory operations of the attack (galleries, branches, etc.), as regards those partis of the objective which it is proposed to destroy. 39 It must not be overlooked that the enemy may intervene, and the attacks must be arranged so as to reach the objective in spite of anything that he may do. The vulnerable parts are the flanks ; that is, both the flanks of galleries or branch galleries which are first made, and also the flanks of the combined scheme. It will thus be necessary — (i) To make the scheme so that the galleries, etc., will be close enough together as regards the front (and as regards depth, if the depth available makes it necessary to have galleries on different levels) that the enemy can not get through without being destroyed ; or, in other words, to ensure that the whole of the ground suitable for mining is within the radii of the rupture of the mines. (ii) To cover the flanks by galleries or branch galleries echeloned back. 12. The judicious placing of the different branches, so that they support, without running the risk of damaging each other, must be the subject of a special study based on the knowledge of the effects of underground charges. Time being of capital importance in a mining attack, especially when the enemy counters, it is necessary, in order to progress steadily and at the maximum pace — (a) To estimate, before starting work, the amount of per- sonnel (engineer units, infantry parties), material, tools, and explosives required. (h) To settle the employment of the available means on a detailed working plan. EXECUTION OF THE ATTACK. 13. The execution of the attack as regards mining does not present any particular ditticulties in suitable ground, as long as the enemy is not met with. If the enemy is not already on the lookout, endeavor must be made to pass without his knowledge, and consequently avoid doing anything which might attract his attention (as hiding of the spoil, making as little noise as pos- sible, etc.). But it is absolutely indispensable to be always ready to take the offensive if the enemy is encountered. There must, therefore, from the very first, be an organized lookout service, including : (i) A watch above ground. If the enemy does not take very careful precautions, it may be possible to recognize from certain 40 signs (p. g., spoil heaps) that he has commenced mining, and sometimes actually to locate his shafts. (ii) A watch below ground (listening galleries, etc.). Even if the shafts are at a relatively long distance from the enemy, lis- tening must be arranged from the very first, in order to train good listeners and to accustom them to the particular ground. The maximum distances at which mining can be heard are very variable (from a few yards in ground in which sound travels badly, such as clay, up to 50 yards, and even more, in soil like chalk, where it travels easily). 14. If the enemy tries to bar the way by counter-mining, a breach must be made in his system, so that, in spite of him. the galleries may be driven to their objectives and the charges may be placed in accordance with the scheme. The underground struggle which will then ensue must aim at clearing the ground by blowing in the. enemy's galleries, and at holding him to one part of the front whilst the attack passes elsewhere (to one side, above, or below) by working quicker. To do this successfully it is necessary : (i) To get ahead of the enemy and strike before he can strike. This requires an accurate plan of the mines, a well-organized system of information, and decision and rapidity in execution. (ii) To go for the flanks of the enemy's galleries, which will thus be put out of action for a greater length than if the attack was directed head on; all the more so because the sides of branches and galleries offer less resistance to the explosion. (iii) To strike as hard as possible. Generally speaking, in the course of an underground struggle there is no advantage in producing effects above ground (craters), ('raters, in fact. have the disadvantage of producing an obstacle on the surface over which the attack must move. Camonllets with maximum charges should be used, which will vary with the depth at which they are placed. (iv) To Strike only when within good range. This requires great coolness. Every explosion necessarily causes a temporary delay in the attack, hecause it will damage pari of the gallery leading to the charge, A mine should only he tired when it is considered that it is likely to do more damage to the enemy than to ourselves. jr.. on reaching a suitable distance from the objective the mine chambers must be formed. Their number and the charges used will depend on the effect that is to he produced Results 41 above ground now' being required, common and even over- charged mines will be used. IV. DEFENSE. 16. The usual measures of precaution employed in ordinary warfare above ground must be taken below ground whenever the distance of the enemy and the nature of the soil do not exclude all possibility of a mining attack. With this in view, it is necessary to have — (i) A lookout service (observation of enemy's works above ground, listening posts). (ii) Means of defense (counter-mines). 17. Close observation of the enemy's works above ground will sometimes give useful indications (an abnormal amount of spoil or spoil of a different color to that of the surface strata). 1 It will sometimes even establish the positions of his shafts. Cer- tain characteristic noises (such as the rumbling of trollies) will also indicate tunneling in the area where .they are heard. 18. More reliable reports can be obtained by the listeners (engineers or infantrymen) placed in the listening posts at the end of galleries constructed for this purpose. Their duties are to note the underground noises that they hear and to judge their direction and distance. 2 When the listeners have found indications of the enemy's activity, their observations will be tested and interpreted by officers. 19. The systems of counter-mining are based on the same principles as offensive mining, because they must insure the possibility of counter-attacking with success if the euemy attacks. They will, however, be pushed out only to such distance as may be necessary to arrest the enemy before he is in a position to reach our lines, and only the portions of the scheme essential for this purpose will be made beforehand. Prudence must be exercised in making them, for they may be interpreted by the enemy as an offensive and thus lead to a mine warfare which is not desired. 1 This lookout is one of the duties of the infantry (Instructions of Dec. 4, 1915, on Liaison I. — B.). Add the examination of aeroplane photographs. 2 Engineer units will not usually be able to provide sufficient listeners. It is, moreover, easy to give the infantryman enough instruction, before mine warfare is commenced, to make use of him as a listener. 42 If the enemy attacks, the best method of stopping him is to undertake the destruction of his mining system by a resolute counter-offensive. It is only in this manner that decisive blows can be struck at him. A consistent system of establishing a barrage of mines and waiting till the enemy is at close range before using them may have local and temporary results ; but its employment should not be a matter of course. As in the attack, the camouflet will generally be. employed. Cases, however, will occur where it may bo advantageous to employ heavy charges (common or even over- charged mines) in order to clear the ground on as extended a front as possible. Craters between the two lines of trenches are not open to the objections in defensive which they are in offensive operations. 20. If the enemy's shafts have been located, they should be attacked with artillery and trench mortars. Even if they are not seriously damaged, an appreciable delay in the enemy's working may be anticipated. Local attacks must 'also be taken into consideration. The ob- ject of these may be either to put an end to mine warfare by gaining possession of the ground where the enemy's operations begin, or simply to attack the entrances of the enemy's shafts with explosives. In this latter case the importance of the destruction which can be done must not be exaggerated. APPENDICES. APPENDIX I. Arrangement of a Mine System. 21. Depth. — The maximum offensive or defensive power is reached when the whole of the ground in which mining is pos- sible is secured. As mining absorbs a large number of men, in- genuity must be exercised to secure this condition with as much economy as possible; that is to say, the development of works which are not likely to be indispensable must be avoided. There may be galleries at one, two, or even three levels, according to the depth of ground that is suitable. At certain points on the front there actually are galleries on three levels. r6les of the different parts of the system. 22. The different parts of the system must mutually support each other. The flanks must be guarded. These conditions have been secured in attacks during the present war by following well-established methods : (i) Galleries placed at such distances apart as to be mutually supporting. The distance depends on the depth ; the greater the depth the greater the radius of rupture that the mines may have. In a system at several levels, galleries on the lower ones will therefore be less numerous than those on the higher levels. (ii) Galleries at wider intervals, the intervening ground be- ing held by branch galleries off the main galleries or off the cross galleries joining up the latter. (iii) Protective arrangements for the flanks, made either by branch galleries off the flank main galleries or by special gal- leries from which branches or borings are driven outward. (43) 44 23. Although they have incontestable advantages, croM leries have proved disadvantages — danger of affecting the whole system for quite an appreciable time if successfully damaged by the enemy and -great vulnerability when too close to the enemy. It should be laid down, therefore, that there should be cross galleries connecting all parts of the system, but a sufficient margin should be kept between, them and the limit of possible action of the enemy's mines. 24. Mine dugouts. — Mine dugouts or lodgments, as they are also called, must be made behind the first line, in spite of the extra work entailed. Their establishment in front of the first line — an arrangement, however, rarely met with — has led to disappointing mistakes. Trenches normally in occupation are to be avoided (interference with the movement of troops occu- pying them and with removal of spoil by working parties). Starting from the front-line trench will be exceptional, and will only occur when it is absolutely necessary to gain ground to the front rapidly (when an enemy attack has nearly arrived within dangerous distance). 25. In the case of an important attack a good arrangement is to establish the mine dugout in an inclined great gallery at suffi- cient depth to be proof against heavy shells. Large boring ma- chinery could be used for this. Shelter for ;i portion of the men on duty and the various offices and stores necessary (com mand post for the officer on duty, with a telephone room: first- aid post; stores for life-saving apparatus and explosives) can be provided there. 26. Entrance to mines. — The inconvenience of shafts (difficul- ties of bringing men and material to the surface, ventilation, the feding of insecurity which they Inspire in the miners) has been definitely reported in the majority of the cases in which this form of entrance has been used. To these disadvantages must be added groat vulnerability, particularly in the case where shafts are made within the galleries (winzes or staple pits) in order to gain depth rapidly when quite near the enemy. Shafts are only a last resource (pis-aller) and should be em- ployed only if conditions make it absolutely necessary to ge! quickly to a greal depth or the ground is sloping toward the enemy, etc. An inclined gallery should always be made alter- wards if possible. Depth ran always be gained by giving tin' galleries a steep slope (2/5 and even more has been used). 45 APPENDIX II. Execution of the Work. 27. Documents. — The opening and keeping up to date of the books, etc., mentioned in " L'Ecole de Mines (Livre de l'Offi- cier)" — mining diary, listening diary, plan of galleries — are obviously as indispensable in trench as in siege warfare, but this has often been lost sight of. It is convenient to use the conventional signs laid down in "L'Ecole de Mines (Livre de KOfficier)," Mining exercises 295. 28. It is important to have as accurate as possible a plan of the galleries (levels, base carefully measured), so as to obtain the best results from the means available and leave as little to chance as can be helped, and to put down with sufficiently ac- curate approximation what is known of the enemy (results of listening, craters, etc.), in order to be in a position to strike him with certainty. It is also necessary, when a relief occurs, to be in a position to furnish the units which take over with as accurate and detailed information as possible. It is of course necessary to begin by fixing the objective to be reached as ac- curately as possible. The existing maps are not always suffi- ciently exact and must be corrected and completed ; assistance should be obtained if necessary from the topographical sections. ORGANIZATION OF WORK. 29. The organization of the work has. considerable, influence, on the rapidity and efficiency of its" execution. For an opera- tion of any importance careful study is required in order to decide what personnel, tools, material, and explosives are neces- sary and how to get the fullest value out of them. (Arrange- ment of the various working parties so that they work- in with each other and that no time is lost. ) Here, again, guidance can be obtained -from " L'Ecole de Mines (Livre de rOffieier)/' particularly as regards — ( i ) Organizing the reliefs in such a manner that working parties always return to the same job (gallery, branch, or shaft). ( ii ) Organizing the regular supply of tools, materials, and explosives and regulating their transport so as never to be stopped by lack ofl. material or by damage to tools, 4G (iii) Establishing as soon as possible the various offices and depots required to insure smooth working — command post for the officer (or officers), telephone office, first-aid post, depots of materials and tools, and small depots for explosives. TYPES AND CONSTRUCTION OF GALLEB1ES. 30. Experience has proved that our various types of under- ground communications meet the requirements of the war and that there is no advantage in limiting ourselves, as the Germans do, to a very small number of types. It is difficult, moreover, to imagine any scheme of attack without some galleries of large section. It is true, as some officers have noticed, that speed is not gained by decreasing the section below the size of the " small gallery." * But the " charging gallery," 2 which has much more resistance than the larger types and allows of much more rapid tamping, is none the less very useful and effective in the attack. 31. In ground where it is easy to work and difficult to listen. Russian saps have sometimes been used with success. Progress is rapid; ventilation can be obtained or, at any rate, assisted by air holes bored to the surface. In some cases these saps have been lined with ogival frames. On some occasions the roof was blown in by long charges at the same time as the mine was fired, and by this means communication trenches were formed which permitted the enemy's position to be reached under cover. 32. Earth borers have given good results where the ground was sufficiently hard. "Cumbrous and noisy, these machines can hardly be employed close to the enemy. It has, however, some- times been noticed (in the Vosges and Champagne) that the noise of the borer has thoroughly scared the enemy and caused him to fire a number of mines prematurely. In any case in an important attack earth borers can be very usefully employed to excavate portions of the main galleries at a distance from the enemy. Bore holes, which have the reputation of being difficult to make and not very effective, have been used with success in a certain number of ca^es (for listening or placing a camoufiet). i " Demi gallerie." — Width. 1 meter (3 feet 4 inches) ; height, 1.30 to 1.50 meters (4 test 3 inches to 4 feet 11 inches). > " Rameau de Combat." — Width, 0.60 to 0.65 meter (23 to 25 inches) ; height. 0.70 to 0.80 meter (27 to 31 inches). 47 33. There iarno objection to the use of blasting after the mine fighting has begun and when there is no longer any fear of it attracting the enemy's attention ; besides, it is difficult to locate where blasting charges are fired. 34. The rapid removal of spoil is of first importance, for this almost always regulates the rate of progress. The ample provi- sion of suitable plant is indispensable when an important at- tack is undertaken (narrow-gauge tram lines, trollies with noiseless wheels, winches, moving platforms, according to cir- cumstances ) . The concealment of the spoil is an equally difficult problem. Sometimes, when there is lack of places which fulfill the neces- sary conditions (abandoned trenches, quarries, wooded ravines), special trenches must be dug into which to put the excavated earth. 35. Electric lighting and noiseless ventilating apparatus are indispensable for carrying out large mining operations under favorable conditions. APPENDIX III. THE UNDERGROUND STRUGGLE. 36. Lookout for the enemy. — From the moment work is com- menced the nature of the ground must be studied, particularly from the point of view of the detection of underground noises. For this purpose listening schools must be organized, so that listeners may be trained. They will prove most valuable when the enemy is eventually met with. This measure is recommended in " L'Ecole de Mines," but it is just as well to call attention to it. The interpretation of the sounds heard by listeners is the business of the officers. The results obtained will be of greater value if the officers possess long mining experience, and have a thorough knowledge of the methods and ruses of the enemy to whom they are opposed. 37. As has been said above, it is not enough to confine the lookout to below ground. Observation of surface works and photographs will sometimes be of assistance in locating the en- trances of the enemy's mines. His craters, if he makes any, must be plotted on the plan w T ith great care. In certain cases (Artois) the Russian saps made by the enemy were accurately located by the vapor which rose in the morn- 48 ing from the ventilation holes. In Champagne* (Bote Sabot) enemy gallery entrances were detected by means of the smoke which escaped by them after an explosion. The better the plan of the mines the more certain will be the deductions that can be drawn from scraps of information obtained. 38. Effects of mines. — Every engineer officer should know what is stated in the " L'Ecole de Mines (Livre de roffirieri" as regards the effects of mines. He should make it a rule to note down whenever possible the effects, of the service explosives in the particular ground where operations are being carried out. It should be noticed that the figures given in " L'Ecole de Mines " may possibly be found to be incorrect, especially in rela- tion to the huge charges which are now frequently used. The special precautions to be taken in firing large mines should not be overlooked. (See the notice of July 19, 1915, on the firing of overcharged mines. ) 39. Destruction of hostile galleries. — It is always a rule to try and strike the enemy in flank. This can be done either by mov- ing in the right direction, or by drawing on the enemy to expose his flank. If the listeners carefully follow the enemy's move- ments, 1 there is little danger in allowing him to come quite close. The following is an example : In front of Frise the enemy got between two galleries "A" and " B," joined by a cross gallery " T," passing within range of the head " C " of a branch " II." 1 " Des 6eoutos suivies." This phrase conveys the idea :hat the lis- teners move as the enemy advances and also keep up continuous listen- ing.— (Translator.) 49 " C " was charged, listeners in " T " and M B " followed the enemy's work closely. As the enemy was about to reach the cross gallery " E " a camouflet was fired in " C" The wall of the cross gallery was then cut, and the hostile miners who were shut up in the head of their branch by the explosion were made prisoners. 40. Impressed by the inconvenient effects of badly placed camouflets, some officers have thought that it is better to let the enemy fire them than to do so oneself, and that the ideal would be not to fire any, but to entice the enemy to make premature blows. It is in fact easy to conceive that in the presence of an enemy who is not quite sure of himself and a bit demoralized progress can be made, although only a very restricted number of camouflets are fired. In most cases, however, the way must be opened up by force, and to do this one must be able to strike heavily and opportunely. It will, of course, often be desirable to entice the enemy to explode his charges prematurely or to get him to place mines at points where he will cause only a small amount of damage. For this purpose noise and silence can be made use of, varying them with the circumstances of the moment. 41. In mining warfare it is of first importance to understand the advantages to be derived from knowing when to be noisy and when silent. Generally speaking, it is desirable that the sounds of work should be as imperceptible as possible. In the clay of Artois, in ground where listening is difficult, numbers of cases have occurred of contact being established, and even the enemy's galleries penetrated without his attention having been attracted. The mining was done with " Sabres Serie Z " or sharpened grafting tools ; the clay was cut off in small blocks and placed on canvas squares stretched on a light frame ; * the sappers wore sandals or sandbags on their feet. Analogous results have been obtained in the chalk of Champagne, where sound travels easily, but if precautions are taken blocks can be cut out almost noiselessly. 42. In most ground mining can not be done in absolute silence, but every effort must be made to reduce noise to a minimum (tools that can be used quietly, rigorous discipline, increased precautions as the enemy is approached). For instance, in 1 " Carries fie toile legerement tendus." This may also mean squares of canvas lightly stretched by men holding them. — (Translator.) 9784°— 17 4 50 certain units screws have been used with advantage in place of nails for fixing the frames. Noise may, however, be made with advantage — (i) To mask an attack which it is desired to make without the enemy having notice of it. (ii) To draw the enemy in such a direction that he exposes his flank to our camouflets (by laying a charge in a branch gal- lery and continuing work at the face of it without any precau- tions as to noise). The tendency of the enemy to work toward noise, which has often been noted, can thus be exploited. (iii) To deceive the enemy as to distance and make him be- lieve the heads of our attacks are very near, and thus induce him to fire his mines prematurely. A pretense of charging can be made so as to induce the enemy to charge in a hurry and to fire before he is within range. 44. If a gallery is in imminent danger of being blown, it should be abandoned after having been shored up so as to reduce the effects of the explosion. Pretense of continuing work should be made by operating a pickax from a distance against the head of the gallery. 45. Continuation of work after an explosion. — Work must be restarted as soon as possible after an explosion. To permit this energetic measures must be taken to restore ventilation. Whichever side can recommence attack first after an explosion Avill have a marked advantage over the other. Deviations should if possible be avoided, as they delay progress. In some casee it may be possible to make a start from the part of the gallery that was tamped and to find the compression chamber, and then ground may be gained rapidly. In others, on the contrary, the amount of ground broken up and affected by a camoullet will constitute an obstacle, and there is no alternative but to work round it. Knowledge of the nature of the ground in which the work is being carried out will allow of a forecast being made as to whether there is any likelihood of being able to utili/.e the com- pression chamber or not. -id. / neapeeted meeting with the enemy. — As soon as contact is gained measures should always be taken to be in a position to prepare a camOUflet qUteWy; a certain amount of explosives and materials for tamping must be at hand. To deal with the enemy's galleries, should they be broken into, there should be available — 51 (i) Means of blocking (chevaux de frise, sandbags lashed to- gether with wire, screens that can be quickly placed and fixed on our side of the breach). (ii) Daggers and automatic pistols and a small supply of asphyxiating grenades (employed by miners of old and several times used in the course of this war). DANGER OF ISOLATED ATTACKS ', NECESSITY FOB PROTECTION OF THE FLANKS. 47. To make an isolated attack is to invite almost certain failure; this mistake, which occurs very frequently, has in- variably met punishment. The operations at La Pompelle furnish an interesting example. Toward the end of 1914 the Germans ran a gallery at a deep level against the fort of La Pompelle and exploded a very heavily charged mine inside the French lines (Dec. 31, 1914). Distance between opposing trenches, about 150 yards; subsoil, chalk. The French defensive system, which was at a high level, was of no use. It was at once deepened and developed. The course of these operations (extract from report of Capt. Cussenot) is shown in the following rough sketch : German Trenches French Trenches The enemy, finding himself blocked at "A" on February 27, abandoned "A B " for " B C." While he was working in " B C " the French branch " F D " struck "A B " (depth 82 feet). The captain in charge of the attack with a small detachment- en- 52 tered it, explored this part of the enemy's works without being discovered, and exploded a mine of 1,433 pounds of cheddite at "D" just at the moment that the enemy's miners, attracted by the noise, were attempting to take possession of the charge. The enemy was evidently much shaken by the destruction of his gallery and the asphyxiation of a number of men, for when he returned to work at " B," the head of the part not destroyed, he fired a mine (March 8) which was outside the French line and did no damage wmatever. - The enemy's gallery was again cut by French camouflets on March 22 and April 30, after which the enemy abandoned the struggle. On April 2 the French again penetrated into the enemy's gal- leries, this time at " H," where the effects of the mine on March 22 could clearly be seen. The gallery in question had been made by professional miners, not by pioneers; it had no sheeting, only frames made of logs and railway sleepers at about a yard interval. Owing to the absence of sheeting, the effects of our "blows" had been con- siderable, especially in the upper portions. The enemy had lacked prudence, and judged, owing to the depth of his galleries (65 to 80 feet), that he could work absolutely undisturbed. Be took no precautions to guard his right or left, and this led to his undoing. It must be added, however, that the French attack was carried out with remarkable vigor and decision. MINING IN COOPERATION WITH A GENERAL OFFENSIVE IN NIMH! OV THE ENEMY'S RESISTANCE UNDERGROUND. 48. The ideal to seek is obviously to trot within range of the objectives without exciting the enemy's attention, and for this reason it is desirable to select objectives in ground where no mine warfare has taken place. But. whatever precautions are taken, one can never be sure of not meeting the enemy. It* he is encountered, however, it is not sufficient merely to heat him: he must be beaten in such a way that the final "blows" can he made at the proper moment. This is difficult to accomplish, hut it has been done on several occasions. It is not a question here of small operations which have as their principal object the employment of mines. In such the time of attack is subordinated to that of the " blows "' 53 49. In this connection the brilliant mining attacks made before Carency in May, 1915 (report of Lieut. Col. Lebatier), may be quoted. At Carency mine warfare had begun in the early part of 1915. When a general offensive was decided on, the enemy was very active underground. Six mining companies were opposed to the French. The Germans fired mines almost daily, sometimes several on one day. The French, it may be said, replied to them with interest. Nevertheless, on May 7, the French had 17 new mines ready, with charges varying from 660 to 3,300 pounds of cheddite. They were blown on May 9, the day of the attack. Their effect was considerable; the wire entanglements were flattened, and the German trenches filled up for lengths varying from 50 to 80 yards. Communication to the rear was cut, and prisoners were made in the isolated portions of the enemy's trenches. Flanking works, armed with machine guns and trench mortars, were destroyed. Flanking fire from works which remained in- tact and from rifles was rendered valueless by the lips of the craters and by the general upheaval of the ground. At the same time the underground works of the enemy were destroyed. The mine chambers, for the most part charged and fuzed, were smashed, or the mines rendered innocuous by the interruption of the fire arrangements. Numbers of tunnelers were buried in their galleries, others surrendered to the French miners or infantry. Thus the fear of having to cross an area checkered with mines, which affects even the best of soldiers, was dispelled from the minds of the attacking columns. APPENDIX IV. Methods of the Germans. 50. The following information has been collected for the most part from reports furnished by engineer officers who have taken part in mining operations. The German methods have naturally developed since the beginning of the war. They have also varied in different sectors, according to the energy of the commander and the standard of efficiency of the personnel. For instance, one German army advocates the employment of camouflets, while another considers they should only be used in exceptional circum- stances. This must be borne in mind when studying the infor- mation given below. 54 51. Methods of attack. — At Fontenelle (rocky ground) the Germans have employed the following procedure: (a) They pushed several saps to within about 50 yards of our trenches, joined up the heads, so as to form small works, by a cross trench which served as a starting point. At the same time they started galleries from the sapheads. (b) They first made Russian saps for a length sometimes of 80 yards. Manholes stopped up by day were used for watching at night. From the heads of the Russian saps two or more branch galleries were commenced. A system of this kind was found and explored by a French patrol. It was destroyed by a charge of 1,100 pounds of cheddite. 52. At the Croix des Cannes the enemy always tried to extend his attacks at the flanks. He even got so far as to cut the ex- treme right French branch gallery; but this the French turned to their advantage, as they were able to penetrate into a hostile gallery which led into an abandoned compression chamber. 53. At Eparges " the Germans seem to have been working on the principle of a close system of counter mines comprising sev- eral lines of charges." A striking change of tacties was noticed after a little time. Instead of operating with small charges <>n their most advanced line, as at first, the Germans began to use very large mines. As the depth was increased, so the size of the mines increased. 54. The German pioneer often seems to adopt waiting tactics. He arrives near oue of our attacks, prepares a charge there, and then disappears completely for quite a long time without any listening post being able to detect him. He thus allows our real attack to pass him, and when it arrives near enough to menace the gallery which leads to the mine chamber he charges it and blows, thus cutting our attack far in and for a great length. 55. in Champagne (region of Perthes les Burins) the Germans had galleries Oil two levels. While they attracted the attention and efforts of the French to the upper level, which W8J3 ."><> to 50 feet deep, they constructed deep galleries at so feet, which they pushed under the front line. 1 The French got wind of this 'This is an application of the teethed Sug ge s ted b$ the Oennan " In- structions tor engineer duties in siege warfare" (art. lit;?). (This lias been translated into French under the title of "Instruction Mir lc Service du Pionnier dans la Ouerre de Siege.") "In such a case (attack of a part of the enemy's position defended by counter mines) it Is desirable to push several galleries toward the ob- jective as quickly as possible and without trying to avoid attracting at 55 through the particular resonance of the chalk soil of Champagne and were able to evacuate their galleries in time. 56. After the offensive of September-October, 1915, the Ger- man system of mines in the Bois Sabot and at Souain was explored : (a) At the Bois Sabot 10 mines, disposed on a salient about 150 yards in length, were pushed out directly from the first line. There were no mine dugouts. The entrances were either by deep shafts (4 by 2 feet 7* inches) or by inclined galleries (4 by 2 feet 7i inches), with a very steep slope (t 7 tt to &), or with an average slope of -&. The mines were connected In pairs by means of cross galleries. They comprised a high-level system, 23 to 26 feet in depth, and a low-level system, 39 to 42 feet deep. Certain galleries had shafts a good distance in from the mine entrance, placed in branch galleries 3 feet 4 inches by 2 feet 3A inches. The enemy, no doubt had been anxious about our work, and judging his depth was insufficient had desired to increase it rapidly. (b) At the salient of Souain, 19 branch galleries, arranged in groups, appeared to cover portions of trenches which were of importance, either because of their position or because of works which they included (concrete observation posts, for example). The greater part of the branches seemed to have been hastily constructed ; their walls were irregular. It appeared as if there had been no fixed method of gaining depth. There were mine chambers^ at the ends of some branch galleries. (e) At the salient B (northeast of St. Hilaire-le-Grand), the system was composed of 11 branch galleries starting from the front line. There were no dugouts at the points of departure? Average slope ■& to ry day. however, or at the very latest as soon as intense artillery fire begins, they should be taken back to their proper positions. ."». Machine guns may always be sited in the front trench in thick woods or under other exceptional conditions. The decision in such cases will rest with me: suggestions should be submitted. (Signed) v Hokhn. METHODS OF ATTACK OF THE GERMAN INFANTRY. In all the general actions which took place in the neighbor- hood of Verdun between February 21 and April 15 the German corps attacked with their divisions side by side. In exceptional cases, when the extent or importance of the zone of action allotted to a corps only allowed of the engagement of a single division, the other division remained resting behind ready to relieve the division in the front Line. I. Zone of Action and Dispositions of the Division. The extent of the zone of action of a division of three regi- ments (7,200 rifles) varied from 1,000 to 2.500 meters, accord- ing to the importance and number of the successive objectives, e. g.— (1) On April 11 the twenty-first division, starting on a front of about 1.000 meters (Douaumont Fort (exclusive) to the southern branch of the Fausse Cote Ravine), was required to attack in the general direction of Verdun. Its zone of action had an average width of 800 to 1,000 meters, the successive objectives being Bois de la Caillette, Fleury- devant-Douaumont. Fort St. Michel. (2) On March 6 the twenty-second reserve division started on a front of about 2.500 meters from Forges Brook (500 meters in front of Forges) to the Meuse. Its zone of action had an average width of 2,000 to 3,000 meters, the objective being the line Bois des Corbeaux-Bois de Cumieres- Point 265 (east of the Bois de Cumieres). (1) Is an example of an action with a distant objective (nar- row zone of action, successive objectives). In this 'case the twenty-first division had two regiments side by side in the front line with one in reserve. (2) Is an example of an action with a limited objective (wide zone of action, a single objective). In this case the twenty- second reserve division had its three regiments side by side in the front line. (61) 62 in both cases the density of the frontage of attack was almost the same, the front of a regiment varying from 500 to 800 meters. II. Dispositions of the Regiment for the Attack. Whatever the disposition of the division might be, the regi- ment was generally disposed in depth in successive battalions: One battalion in the front line, two battalions in the reserve, echeloned in depth at distances varying with the nature of the ground, the nearest battalion being ready to move up either to support the attack on the first objective or to undertake a fresh attack beyond that objective, the farthest battalion often rest- ing, and in such eases destined for the relief of exhausted units. III. Dispositions for a.xd Method of Attack uy THE Battalion. dispositions. The Infantry battalion was nearly always deployed in two lines. The first line was generally composed of two companies side by side, which deployed either in the departure trench or in the last cover from which the assault was to be launched. The second line remained in the support trench in shelters or behind cover. METHOD OF ASSAULT WAVES. GENERAL PRINCIPLES. (1) Each attacking line was always given a definite and limited objective (its width being equal to the Croat of attack and its depth seldom exceeding that of two successive lines of trenches). (2) The assault was not launched until tin 4 artillery had com- pletely wrecked the trenches, destroyed (he obstacles, and ren- dered the defenders incapable of resistance. (3) The actual assault was preceded by reconnaissances pushed forward toward the objective with a view to ascertaining whether the artillery had achieved the desired effect These reconnaissances in reality formed the first wave of the assault. It appears that the Other waves did not start unless the first made progress. What has often been regarded as an ordinary reconnaissance Intended as b feeler against our lines has in reality been the beginning of an attack nipped in the bnd. 63 EXECUTION OF THE ASSAULT. The attacking line debouched in several successive waves. The various methods noticed resembled more or less the following type : Three successive waves at 20 or 30 paces distance. First wave (reconnaissances). — One or two squads from each platoon, accompanied by some pioneers and bombers, in skir- mishing order and at very wide intervals. Second ivave. — A dense line of skirmishers composed of the main body of each platoon. This line seized the trenches. Third wave. — Composed of the remainder of each platoon and forming an echelon which filled up gaps and carried a reserve of ammunition and material (tools, sandbags, etc.) in order that the captured trenches might be converted. . e6le of the second attacking line. This line was, in principle, reserved for a second assault be- yond the objective captured by the first line. In exceptional circumstances it might be employed to reenforce the first line or rally the latter in case of failure. Note. — The assaulting waves were always deployed. Prisoners were unanimous in stating that they have never seen the employment of columns in the assault. It may so happen, however, that the two waves, debouching in dense lines, may sometimes have had a number of stragglers behind them, thus giving the impression of small columns following the first waves. PRACTICE ATTACK CARRIED OUT DY THE SECOND BATTALION. TWO HUNDRED AND EIGHTH RESERVE REGIMENT (XXII RESERVE CORPS). This battalion recently carried out the following exercise whilst at rest behind the front line. The company formed three, four, or even five waves, which all left the trench in skirmishing order. The object of the first wave was to cross the first French trench and to push forward to within bombing distance of the second trench. There the men lay low, threw their grenades, and leapt into the trench as soon as these exploded. Each man carried six grenades and a small pair of wire cutters. 64 The object of the second wave was to reach the first 1 trench. It acted in the same way as the preceding nave, starl- ing as soon as the latter had crossed this trench. The third wave carried tools, shovels, picks, large wire cutters, and portable obstacles. The fourth wave carried tools and rations. The attack was launched at a fixed hour, watches wer and the waves were started by means of whistle blasts. The men were told off by name to the different waves. THE CONSTRUCTION OF FIELD DEFENSES. 1 The varied conditions under which defensive positions have to be prepared (before or during a battle, in the course of an ad- vance or a retreat, etc.) prevent definite rules for their con- struction being laid down. It is only possible to establish the general principles underlying it. 1. A stubborn defense, organized by sectors, must be abso- lutely assured. This calls for several successive positions — at least two — and, in addition, in order to prevent the enemy from extending after the partial capture of the front-line position, the provision of switch lines from which the enemy can be taken in flank. 2. The distance between positions must be sufficient to exclude the possibility of the rearward position being attacked simul- taneously with the one in front. Each successive position must entail a completely fresJi attack, and above all oblige the enemy to push forward his observation posts and at least a portion of his batteries. Depending on the ground, this distance will, therefore, be from 1 to 2 or more kilometers. 3. Each position will consist of at least two continuous lines, one behind the other. As a rule, the front line will be the main fighting line. This principle may only be deliberately abandoned when the first line is unfavorably situated. Support lines ought not to lie within the zone of artillery fire directed on the front line. On the other hand, their distance from the front line must not be too great, as this might prevent a rapid advance from the support line to repel an assault, to counter attack, etc., it will thus vary between 50 and 100 meters. (See also par. 8, " Communication trenches.") 4. A field of fire of a few hundred meters, or even less in cer- tain circumstances, is sufficient for the front lines of an infantry position. • The greater the extent of our own field of fire and the more extended the view from our own position, the easier it will be for the enemy to observe and carry out counter battery work. 'Issued by general s+aff (Intelligence), general headquarters, October 16, 1916. 9784 »_17 5 (65 ) 66 On the other hand, a very limited view from the position necessitates an increased state of preparedness for attack, which In time will wear down the troops. It is of still greater im- portance that support lines, in which further resistance may be offered after the loss of the front lines, should be screened from hostile reconnaissance and observation, and consequently from artillery fire. They will therefore be traced, in certain circum- stances, along reverse slopes, through woods, etc. 5. The entire circumference of natural strong points (villages, farms, small woods) will be organized for defense and excep- tionally strongly fortified. Where no such points exist dotted works will be constructed as required. Strong points and dosed works may be sited with advantage either within a position or between two positions and formed by organizing sections of the front and support line and their corresponding communication trenches as redoubts, capable of all-round defense. 6. Reliable obstacles will be erected in front of all lines of defense, switch lines, strong points, and closed works. As they will be very heavily bombarded by artillery and trench mortars, it is advisable to construct them in several rows with intervals. Electrified wire entanglements are only of value as long as they are not exposed to heavy fire. In quiet times they permit of the garrison being reduced with safety. Where electrified entangle- ments are used precautions must be taken for the safety of our own troops. 7. Skillfully traced communication trenches must be liberally provided to connect the various lines of each position. They considerably facilitate the execution of counter attacks, and when it is otherwise tactically feasible, they enable a large part of the garrison to be kept in the support and reserve trenches. This diminishes casualties and spares the troops. In addition, there must be a sufficient number of approach trenches leading up to the position, if sufficient cover is not pro- vided by the form of the ground. When constructing com- munication and approach trenches they must be organized ac- cording to requirements, to serve at the same time either as switch lines or as the flanks of closed works. 8. Deep and narrow trenches afford good cover but circulation in them is difficult and they soon fall in. A certain ratio must. therefore, be observed between depth and width. High para- pets are to be avoided if possible, as they are very visable, are 67 easily destroyed, and then fill up the trenches. As a general rule, as a protection against enfilade fire, infantry trenches should be well traversed, while a zigzag trace should be given to communication and approach trenches. 9. Shellproof dugouts (mined and concreted) have proved of great value. Their occupants, when not overcrowded, have lived through repeated bombardments of long duration and of the greatest intensity. It is advisable to construct numbers of small dugouts (for 20 men at the most), each provided with several convenient and safe entrances. In the main fighting line, or close behind it, a garrison capable of repelling a sur- prise attack must be accommodated in shellproof dugouts, the rest of the garrison being in similar dugouts in the support and reserve lines of the position. Previous to operations of our own, in which large masses of troops will be employed, a suffi- cient number of shellproof dugouts must be constructed in the front-line trenches. It is essential to provide underground shelters for troops held in reserve close behind the infantry position, in order to protect them as long as possible from the fire of the enemy's artillery. 10. With a view to the rapid detection of a hostile attack, observation of the enemy's position, both from the front and sup- port lines, even under the heaviest fire, must always be possible. In the front line the most suitable means of observation are periscopes passing through the roofs of the dugouts. Observa- tions from loopholes is certainly preferable, but since it is hardly possible to hide them, most of the loopholes in the front line will be destroyed or buried by the enemy's fire. Similarly, infantry sentries posted without shelter in the front line will soon be put out of action, and do not therefore insure timely warning of a hostile attack. In the second-line position observation will be mainly carried out through loopholes. Observation posts must be hidden and made as shellproof as possible. 11. Frontal infantry fire to repel an assault will be delivered over the parapet from rifles, machine guns, and automatic rifles. When the distance to the enemy's position is very small, before allotting machine guns to the front line for frontal fire it must be considered whether they can be brought into action with sufficient rapidity ; if not, they must be posted farther in rear, and, whenever possible, in commanding positions. 68 12. After frontal lire the chief consideration is flanking tire. The latter enables an extended front to be defended with a minimum of effectives. It may be brought to bear from the position itself, the trace of which should be suitably broken, or from flanking positions, situated to a flank and slightly retired. Automatic rifles and machine guns are particularly suitable for this work. Flanking fire from a position to a flank and slightly retired (from the second line or from special flanking positions) pre- sents the advantage that the emplacements are not so liable to be out of action by the enemy's fire. In positions with a good command, in certain circumstances concrete emplacements with suitably masked loopholes can be constructed and will be of great utility. . Light quick-fire guns are also suitable weapons for flanking fire. 13. Infantry positions must be selected, wherever conditions permit, with an eye to the deployment of artillery. The artil- lery require — (a) Suitable positions for main observation posts. Observation posts must be covered by the infantry positions. and, whenever feasible, must be sited so far back that they are not exposed to fire directed on the infantry lines. In addition, they should afford a view of the whole of the ground in front of the infantry position. (b) Concealed battery positions at a suitable distance — i. e., a distance at which the artillery can carry out its task — from the enemy. The long range of our guns should not lead to their being kept as far in rear as possible. The length of the tele- phone lines entailed by this is a reason for avoiding it. On the other hand, batteries should not be placed in positions which are in the zone of artillery fire directed against the infantry. (c) Cover that blends with the landscape, in particular, shell- proof shelters for both the personnel and the ammunition. Suitable arrangements, in accordance with the above, will be made for the artillery reserves, when these are engaged. 14. To enable commanders to exercise their command, even during a hostile attack, the battle headquarters of sector (regi- mental) and subsector (battalion) commanders will be shell proof and situated sufficiently far forward and so sited that the* commanders concerned can maintain constant communication, 69 even by means of runners, with each other and with the most advanced points of the fire line. They should thus be in a position to throw in their reserves at will at decisive points. Touch between commanders and their troops and their personal influence on the fight must be insured in all circumstances. It is most desirable that battle headquarters should command a view of the battle sector concerned and of the surrounding coun- try. (See par. 10.) The same remark applies to the battle headquarters of the higher commanders. Where this is out of the question, owing to the nature of the ground or on account of the zone swept by the enemy's artillery fire, a sufficient number of observation officers from the staff concerned will be pushed forward to suit- si ble points. Communication with these officers and with other important observation posts must be insured. 15. Reliable transmission of information from the front to the higher commanders and vice versa is of special value and re- quires most careful organization. Large numbers of telephone lines are required; nevertheless they can not be counted upon during a heavy bombardment. Other means of communication (light-signal apparatus, other methods of signaling, carrier pigeons) must therefore be always available and their efficiency frequently tested. Sound signals (gongs, bells, sirens, etc.) have proved very useful for alarming garrisons. 16. Speaking generally, the improvement of conditions of liv- ing among the troops should be considered in the organization of defensive positions. This includes hutting^ water supply, the improvement and construction of roads, bridging, and cut- ting tracks. Of especial urgency is the development of a field and light railway system for bringing up ammunition, supplies (dumps in second or third line, if required), building material, etc. 17. Positions will be constructed in accordance with definite working plans drafted after careful reconnaissance. The rainy season will be taken into consideration in both the construction and the improvement of positions ; for example, an approach trench will not be taken along the bottom of a depres- sion but along the side. Drainage arrangements must be com- pleted during the dry season. 18. The maintenance of extended positions requires a con- siderable amount of labor. In the case of retired lines and po- 70 sitions, owing to a scarcity of labor, the construction of the main framework must frequently suffice; that is to say, the construction of dugouts, obstacles, observation posts, tlankiim positions, ammunition stores, drainage system, etc. Fire trenches and communication trenches will be marked out, but their execution either entirely or partially postponed. The maintenance of such positions must be taken in hand periodically unless completion is to be abandoned. INSTRUCTIONS FOR MINE WARFARE. TACTICS. 1. Objects of Mine Wabfare. Attack. — To drive galleries under the enemy's works in order to destroy them and their garrisons. Defense. — To drive galleries to intercept those of the enemy and to destroy them at such a distance from the defender's works that the latter are not damaged when the mines are sprung. Mine warfare commences when the attack and defense meet underground. Every mine sprung, including his own, blows the miner back ; therefore after fighting has begun the defender is forced to engage in active mining. The limit of length of galleries driven by hand is 100 meters ; 1 beyond this machines must be employed ; neither we nor the enemy have yet got- a satisfactory machine. Mining is slow and exhausting work ; this means of warfare should therefore be regarded as a last resource by which to capture a position. . A defensive system should be made round every point of tacti- cal value for flanking fire or observation situated within 100 yards of the enemy. When the opposing lines are very close the defensive systems of both sides meet underground. Active mine warfare then ensues. 2. The Principles of Mining Schemes. Offensive. — The plan of attack must provide for the destruc- tion of the enemy's position at several points simultaneously on a broad front and assist in the isolation and capture of his troops. The infantry position must first be advanced by sapping as close to the enemy as possible. If opposition is expected, sev- eral shafts must be sunk, which must be connected by a lateral (71) 72 gallery, from which the offensive galleries will start. Theme galleries must be deep enough to pass under the defense, It i> sometimes best to advance on two levels, engaging the defender's attention on the upper level while the galleries on the lower level are driven at the greatest possible speed. Defensive. — The galleries must be driven straight toward the enemy, at such a distance apart that a maximum camouilet from one gallery will not destroy the next one to it. If the enemy is also mining, the distance apart must be such that he can not pass between any two without being heard; this distance varies with the ground, and is from 20 to 40 meters. The galleries must be pushed forward until their faces are at least 30 meters from the front trench. When these are completed, or as soon as there are men avail- able, a lateral gallery must be made connecting the main gal- leries at such a depth (6 to 10 meters) as will render it sale from heavy high-angle fire and not so far forward that it is liable to be destroyed by mines of either side (about 20 meters in front of the front trenches and 30 meters from the headings of the galleries). As soon as the defender is aware of the enemy's approach on the deep level, he must follow his example, and this process may be continued until the permanent water level is reached or the depth of the galleries is prohibitive. The attack can also be countered by an outflanking movement. 3. Minks. The object of the attacker being to destroy the enemy's works and personnel, this can bo done either by firing simultaneously as 'many mines as possible on a broad front, or by tiring a num- ber of overcharged mines at intervals of half an hour, so as to form large craters and to overwhelm the garrison with stones, debris, etc. The formation of craters enables the attacker to advance his position. Camoutlets should be used to destroy the defender's galleries. The defender., on the other hand, win avoid making craters which interfere wilh his field of lire, and will destroy the attacker's galleries by blowing them in from a Hank by camoutlets. 1 l This is not borne out by the enemy'l mining on our front; his gal- leries hav« often been of much greater length. — ((}. S. I.) 73 The defender should always have a number of galleries ready charged. 4. Cooperation of Various Arms. The enemy's mining operations can be sensibly delayed by keeping his mine heads and trenches leading to them under artillery, trench mortar, rifle, and machine-gun fire, with special reference to flanking and enfilading. The cooperation of all arms is of special importance when it is decided to form craters. Immediately the mine has been fired, the artillery will open on the enemy's position. The effect of this will be greater if it has been possible to induce the enemy to man that portion of his line in greater strength, by driving the men inwards by trench mortar fire, or by any ruse to make him suspect an attack in force. The danger area of the attacker's trenches will be cleared of troops, and the garrison will take shelter in their dug^ outs. If the enemy fires a mine, the garrison of the sector will " stand to " in their dugouts, but will not man the parapet The occupation of craters, which are blown under the enemy's front line, may form either (1) a local enterprise or (2) a part of a general attack on a broad front. As regards (1), the mine may be of assistance when the ob- ject of the enterprise is to destroy shaft heads, ammunition stores, machine guns, or trench mortars, or to secure identifica- tions, but otherwise the concentration of the enemy's fire on the small section of the front captured renders its occupation and organization too costly to be of value. Craters made for the purpose of advancing the attacker's position must not be occupied on the far side until the position is secured underground by pushing forward galleries to cover it. A proper system of backing-up galleries should be arranged before the crater is blown. The organization of the interior of a crater is a difficult operation, especially the construction of a parados, owing to the crater being a good target for artil- lery and trench mortars, by which the defender will endeavor to prevent the attacker from organizing the craters or forming up for an assault. To do this effectively, the defender must have observation of the craters; consequently he must sap out and establish listening posts on them; permanent sentries are not necessary. The obstacle formed by the crater should be improved by knife rests and rolls of wire. 74 As the cratered area Increases, the importance of protection by flanking and machine-gun fire increases In proportion. 5. Chain of Responsibility. The divisional commander lays down general instructions for mine warfare and is responsible for the cooperation (ft artillery, engineers, and infantry. His engineer commander is responsible for the initiation of suitable offensive or defensive mining schemes and for the prepa- ration of estimates. of time and labor. The divisional commander decides (1) whether the position- to be gained are in proportion to the effort required, (2) whether to become involved in mine warfare, or (3) to abandon volun tartly his position as soon as the enemy's galleries are under his trenches. In either case he submits his decision for approval of the corps. When the mining schemes have been finally approved, the divi- sional commander issues the necessary orders to the regimental commanders of the artillery and infantry concerned, and allots to infantry regiments the requisite engineers and trench mor- tars (complete units, if possible). The senior engineer officer in each infantry regiment is the commanding officer of all engineers attached to the regiment and of the permanently attached working parties from infantry or labor battalions. The regimental commander, on the advice of the senior engi- neer officer, issues orders to the latter and to battalion com- manders, who control the trench mortars in their subsoctors. He also arranges direct for artillery support from the artillery formation in his sector. s Bach mine system is in the charge of an engineer officer, under the orders of the senior engineer officer of the regiment. This officer can spring mines on his own authority, in cases of emergency. He must be in the. closest touch with battalion and company Commanders, and all information regarding the mine system or inferences drawn from observation on the surface will be mutu- ally exchanged. Battalion and company commanders have no authority over the engineer officer, except that they ma\ order him to spring such mines as have been prepared to repel an assault. (End id' translation.) 75 ' NOTES BY GENERAL STAFF (INTELLIGENCE). 1. The general principles enunciated are not different from our own, but since this article was written the enemy's limit of length of galleries has been greatly increased. 2. Our experience is that these principles have been followed fairly closely, especially the attack on two levels. 3. The enemy has frequently made craters for the sole pur- pose of improving defilade flanking fire or advancing his position. 4. The description of the role, of artillery and trench mortars for delaying enemy mining activity, and in conjunction with firing mines, is important. The enemy's opinion about the value of craters has changed considerably since this note was written. His persistent and successful holding of craters is very marked. 5. Prominence is again given to trench-mortar fire in the, al- lotment of troops for a mining scheme. THE PRINCIPLES OF TRENCH WARFARE, AS LAID DOWN IN THE FOURTEENTH RESERVE CORPS. Note by General Staff (Intelligence), General Headquarters. — These are the " Corps orders " referred to in " Lessons drawn from the Battle of the Somme by Stein's Group." (Ia/20767). CONTENTS. I. Infantry positions : Page. 1. Trenches 78 2. First-line position 78 3. Intermediate and second-line positions 79 4. Third-line position 80 5. Responsibility for construction 80 6. Dugouts 80 7. Revetment and drainage : 80 " 8. Wire entanglements 80 9. Concrete 80 10. Villages 81 II. Alarm : 11. Alarm 81 III. The infantry combat : 12. Sentries 81 13. Garrison of the trenches 82 14. Supports 83 15. Sector reserves 83 16. Divisional reserves 83 17. Means of communication 84 18. Machine guns 84 19. Minenwerfer _. — 84 20. Hand grenades _ 84 21. Light pistols 85 22. Ammunition „ — , 85 IV. Artillery positions : 23. General.^ 86 24. Ammunition : 86 25. Battery positions 86 26. Observation posts 87 27. Telephones 87 (77) 78 IV. Artillery positions — Continued : Page. 28. Counter-battoiy work 87 29. Survey sections 88 30. Balloons 88 31. Aeroplanes , 88 32. Methods of engaging the enemy's infantry 89 33. LTght signals 89 34. Practice in fire control 90 THE PRINCIPLES OF TRENCH WARFARE. The principles Laid down in the XIV Reserve Corps for the conduct of trench warfare are once more set forth in concise form in the following pages : I. Infantry Positions. 1. Trenches. — All trenches must he designed to allow of their use as fire trenches. Communication trenches must permit of tire to both sides. Except in the case of sentries, every man must, as a rule, use his rifle over the parapet. It must be possible to climb out of every trench, either by means of ladders or sortie steps. This is particularly impor- tant for communication trenches, which otherwise become traps. 2. First-line position. — The first-line position will be held if the enemy attacks. It must, therefore, be repaired Immediately before any other work is undertaken. It consists of the first, second, and third trenches, and should have, if possible* two rows of wire entanglements in front of each trench. There should be at least two communication trenches in each com- pany sector from the third trench to the first trench, but the points at which they enter and leave the second trench should not be opposite one another. The number of dugouts should he increased until there are sufficient to accommodate the infantry garrison that the division considers necessary for the repulse of a prepared attack. Accommodation should be provide!, first of all, for the present garrison and supports in the first trench, and for the present sector reserves in the second and third trenches. Further construction may then be taken in hand. Each battalion sector must have at least two through com- munication trenches. When fighting is in progress, it may be advisable to use one for up and the other for down traffic. The men must know this beforehand. 79 Each company will mark its front-line trench with a red and white l^J screen or board about 20 inches square, painted some inconspicuous color on the side toward the enemy. This will be set up on the parapet, or the parados, in such a position that the enemy can not see it either from in front or from the flanks. By this means the artillery can locate our front. It has repeatedly happened that important letters and sketches have fallen into the hands of the French and English. The troops will be warned of the grave nature of the offense caused by such negligence. Letters must not contain matter of mili- tary importance. The number of documents of military impor- tance taken into the first-line position must be restricted as much as possible. An officer is responsible for any document which he carries on his person. As soon as a document has served its purpose — information to the troops, etc. — it will either be destroyed or taken away from the first-line position. Maps which show the position of trenches may be taken into the first-line position only when our own trenches are merely approximately shown. It is forbidden to take maps into the first-line position which show in detail both our own and the enemy's trenches. Patrols will carry no papers and wear no badges by which they can be identified. Rations, water, and illuminating materials sufficient for at least three days will be stored in the dugouts of the first trench of the first-line position. The rations will consist of iron ra- tions, coffee, salt, sugar, rum or an equivalent, and cigars. The water supply, to which particular attention will be paid, will be made up of water in barrels and mineral water. Lighting will be assured by means of an iron ration of candles sufficient for three days. In addition, electric light, paraffin, acetylene, or candle lamps may be used. 3. Intermediate and second-line positions. — The intermediate and second-line positions each consist of at least two trenches, each provided with two rows of wire entanglements, which should be on pickets, and with the same number of communica- tion trenches as in the first-line position. Each of the present regimental sectors must be provided with sufficient accommoda- tion for at least one battalion. There must be emplacements in all three positions for ma- chine guns and Minenwerf er and artillery and infantry observa- tion posts. 80 4. 'f'hinl-linr position— \\i I bo third-lino position, which Is dug only to the depth of a spade blade, stmiiL: ]M.ints will be constructed when instruction in entrenching is being given and when recruits are being trained. 5. Responsibility for construction. — Regimental commanders will direct the construction of the first-line position; divisions will be responsible for that of the second-line position, and will make their own arrangements with regard to the intermediate position. 6. Dugouts. — The construction of dugouts and observation posts in the first trench of the intermediate and second-line po- sitions will take precedence of work on the second trench of these positions. In view of the heavy guns which the enemy is employing, the thickness of earth above dugouts should be in- creased for any new ones that are constructed. It may be as much as 19^ feet, depending on the nature of the soil, but the depth below ground must not prevent a quick response to an alarm. All dugouts must have at least two entrances. To close the passage between the entrances stultifies the object of having two entrances. Divisions must direct special attention to this point. Dugouts should be constructed under the parapet, not underneath the parados, and the entrances should be in the front slope of the trench. 7. Revetment and drainage. — Revetment, and drainage are essential. Revetting a trench with wire netting and corrugared- iron sheeting is forbidden ; fascines, also, are not suitable, as they form impassable obstacles if the revetment is destroyed. On the other hand, brushwood well secured by pickets and pegged into the sides of the trench may be employed. The pioneer commander of the XIV Reserve Corps will send up as much brushwood and thin pickets as he possibly can, in accord- ance with the requirements of divisions. In arranging drainage, only technically qualified personnel sbould be employed, as the form of the ground, nature of the soil, surface and subsurface water conditions must be taken into account. 8. Wire cntanglcmcnt*.-^\n the wire entanglements of the second-line position, passages which are clearly marked, easily closed, and not too wide, must be left for the use of troops ad- vancing and retiring. The points where roads traverse the trenches must be left open, but be easy to close. 0. Concrete. — The greater distance of the second-line position from the enemy will permit of a more extended use of concrete. 81 On principle, observation posts and important machine-gun em- placements will be built of concrete. 10. Villages. — Villages in the intermediate and second-line po- sitions will be fortified so as to permit of their defense in sectors. During a battle, however, they will not be packed with troops scattered about in cellars and dugouts. Any conspicuous excavated earth will be disguised. II. Ala km. 11. Alarm. — Conditions vary so much on the extended front held by the XIV Reserve Corps that I refrain from issuing a general order dealing with alarms which would hold good for all the divisions. Divisions will issue orders individually and the corps will undertake the printing of them. These orders will be posted up in all dugouts, even those temporarily unoc- cupied. It will generally be advisable to distinguish between an " ordinary alarm " and a " gas alarm," as in each case the pro- cedure differs. It is recommended that the signal for an ordi- nary alarm should be given by mouth (shout, policeman's whis- tle, foghorn, etc.), and for a gas alarm by hand (ploughshare, motor horn, etc.). Orders for alarms will be submitted to me. III. The Infantry Combat. 12. Gentries. — Our entire system of defense depends on the trustworthiness of the sentries in advanced listening posts and in the fire trenches. Sentries must, in most cases, remain in the listening posts even during a heavy bombardment. The sentries in the fire trenches- must clearly understand that on a dark night they must not rely on the sentries in the listening posts or on patrols sent out in front. Every sentry must be convinced that the safety of the position and of his comrades de- pends on his vigilance and his endurance. His task will pre- sent great difficulties under an intense bombardment, when he will frequently be forced to take cover. With regard to the latter point, he must be given definite instructions as to whether he should stand at the entrance to the dugout, whether he should lie down, etc. In no circumstances may observation of the front suffer interruption. There will nevertheless be casualties among the sentries. For this reason the garrisons of the 9784°— 17 6 82 trenches concerned must, be in ;i state oi Instant readin- the dugouts, and the commander will immediately replace any sentry who falls. Sentries will carry the gas mask hang 00 the chest or in the box, with the slings of the mask and of the box around the neck. 13. Garrison of the trenches. — The garrison of the first trench of the first-line position should be strong enough to repulse the enemy's attack, assuming that the men reach the parapet in time, but no stronger. The better the first trench is defended by flanking fire, especially that of machine guns, the more can the infantry garrison be reduced. To man the parapet promptly requires constant observation, good alarm arrangements, suit- able construction of the entrances to the dugouts, practice of the alarm in the form of a regular drill, and, most important of all, observation of the fall of the enemy's artillery fire (lift of bar- rage). Above all, every group commander and every man must realize that the success or failure of an assault depends on his timely appearance at the parapet. It must be made clear to the men that, once in the trench, the enemy will throw hand grenades into the dugouts. Everything depends, therefore, even when the alarm signal is not heard, on not missing the instant at which the enemy's fire lifts, and immediately hurrying to the fire line. Experience has justified the practice of posting sen- tries, armed with hand grenades, at the entrances to the dugouts, to deny approach to the enemy and to facilitate the task of ejecting him. Machine guns which are left in breastworks or trenches (lur- ing the enemy's intense bombardment will be destroyed unless they are covered by very strong concrete emplacements. It will generally be impossible to erect such concrete structures in the first trench. Machine guns must, as a rule, be kept in the dug- outs of their crews until the enemy assaults, and must then he placed rapidly in position at suitable points on the parapet with- out making use of the sledges, as these are too heavy for trench warfare. It is taken for granted that the crews are trained in tiro without the sledge, on a pedestal built up of sand bags. This method of fire must be learned. The resulting disper- sion, which is known to be the disadvantage of this method, is of no account -'it assaulting distance. In order to make the enemy disperse his tire and prevent him locating the positions really employed for thinking tire, the latter must be masked and a number of (lummy positions constructed. 83 14. Supports. — The second trench of the first-line position is garrisoned by the supports, one portion of which is specially de- tailed to defend the trench itself and in particular the entrances to communication trenches, while the other portion consists of strong, specially formed bombing parties, which are held in readiness to rush forward at once to the support of the foremost trench. This maneuver must be practiced as if it were a regular drill. Local conditions may make it necessary to station part of the supports in the third trench. 15. Sector reserves. — The fighting strength of both the front trenches would be soon exhausted if the sector reserves were not put in. They must therefore be brought close up in good time, either into the third trench or into special reserve trenches. In case of an attack, they should be moved forward into the second (or third) trench, to replace the reinforcements which have already gone forward (.the supports) and continue the task allotted to the latter. Should the enemy's fire permit of an ad- vance across the open, this is always preferable to an advance along the communication trenches. The sector reserves must not, therefore, be saved up too long, but must be thrown in early. Otherwise they will arrive too late. Every battle has shown that trenches which are either lost or in dispute may be comparatively easily cleared or recap- tured when this is undertaken immediately. I expect leaders to show the greatest determination and initiative in such cases. 16. Divisional reserves. — The sector commander must be re- lieved of anxiety as to his forces being exhausted too soon by moving up the divisional reserves. They should not be left be- hind in villages in the rear, but should be brought up to re- serve trenches on the battle field as soon as the threatened sector can be ascertained from the direction of the enemy's artillery fire. Whether they stay there one day or several days is a mat- ter of indifference. The divisional commander must rely on re- serves being passed on to him by the corps commander, just as the latter expects them from the army commander. In critical situations it is not sound to quarter reserves in villages immedi- ately behind the front. It has nearly always proved impossible to assemble the troops quickly when they are scattered in numerous cellars, etc., in a village which is being heavily shelled. In such cases the reserves should be in the trenches. Reserves can not be rapidly moved forward without practice. This operation must therefore be practiced in suitable weather. 84 The distribution of the division and the improvement of th«> position also will he decided in the light of the experience gained in practicing this operation. Routes will he marked out. They must lead around villages, which are certain to be heavily shelled. Caw-dry officers will he trained to guide troops Into l)ositions which are unknown to the latter. The Second lie- serve Ulanen Regiment will find guides for the Second Guard Reserve Division; the Fourth Squadron. Sixteenth Dlanen Regi- ment, those for the Fifty-second Division; and the Wiirtteni- berg Reserve Dragoon Regiment, those for the Twenty-sixth and Twenty-eighth Reserve Divisions. 17. Means of communication. — Communication with the front must not be interrupted. Consequently several means of com- munication must be available and kept thoroughly tested (tele- phones, light pistols, light-signal sections, runners, etc.). The principle of metallic circuits will be adopted 'for the front line in order to prevent the enemy from "listening." (For the method of laying buried cable see par. 27, " Telephone 18. Machine guns. — When the ground permits of ma dune guns being employed on commanding points in the second and third trenches with a view to firing over the first trench, every advantage should be taken of it. It is advisable to employ the bulk of the machine guns not in but behind the first trench. WhfiB fixing their siting the possibility of delivering both frontal and flanking fire must not be forgotten. Vsed as an emergency garrison for the Intermediate or second- line position, they may prevent a break through if the enemy succeeds in overrunning the first-line position. .Machine-gun units are particularly suitable for employment as ;i commander's mobile reserve. 19. Minenirerfer. — As soon as a hostile attack is imminent it is advisable to withdraw the Minonwer for Prom the first trench and place theni in prepared positions in the second or third trenches. Light Minonworfer in particular will be site^l in such a manner thai, by making full use of their range and mo- bility, all points where the enemy may be expocted to concen- trate his infantry can be brought under lire, which should bo Hanking tire whenever possible. 20. Hand orcnatlcs. -Training in grenade fighting will be car- ried to the point of thoroughly instructing all officers, noncom- missioned o ffi cers, and men of the infantry and pioneers, Minen- werfer companies, searchlight sections, gunners, and opoctvc t b 85 of the field and foot artillery, as well as those detachments of cavalry which take their turn in the trenches, and the field com- - panies of ammunition columns and trains. Officers and non- commissioned officers must, in addition, know how hand gre- nades should be tested and stored. Our hand grenades are not weatherproof, and in this respect their design leaves much to he desired. When storing them particular stress must therefore be laid on protection against wet. Corps headquarters will en- deavor to maintain the stocks of hand grenades with the units of the reserve corps on the following scale : Infantry regiment 8, 000 Independent infantry battalion (and fourth battalion ninety-ninth reserve infantry regiment) 3,000 Pioneer company . 750 Battery 50 In divisional reserve i 8, 000 In corps reserve , 30,000 Rifles and hand grenades will be kept in the dugouts, not at the entrances to the dugouts or in special stores. 21. Light pistols. — Only white lights will be used for illuminat- ing the foreground. On dark nights, ample use will be made of them. On occasions when small enterprises undertaken by the enemy have led to our first trench being raided and the garrison surprised, this has always coincided with a lack of illumination of the foreground. The second army has been asked to increase the supply of light pistols. (For light-signal cartridges for barrage fire, etc., see par. 33, " Light signals." ) ^ 22. Ammunition. — Iron ration: Rounds. Infantry, per man, carried in the pouches 150 In every battalion sector, per man 150 300 Machine guns : With each gun -. in belts_ 5, 000 Reserve for each gun loose__ 5, 000 10,000 The small-arms ammunition carts of the infantry and of maehine-gun units will always be kept filled. The expenditure of light-signal cartridges and of material for Close-range lighting (grenades, etc.), should be in no way re- stricted by the figures laid down in the instructions issued by the corps. Expenditure in the front-line trenches will be regu- lated only by requirements and will be Immediately replaced from the rear. Thus, as in the case of ammunition, there will be a constant stream of supply from rear to front. The resulting drain on the reserves in the rear will be covered by further indents. IV. Artillery Positions. 23. General. — Each divisional sector must have at least twice as many battery positions as the number of batteries present. Batteries are responsible for keeping these positions in repair. A battery position is net complete until it is provided with ob- servation posts,* gun emplacements, dugouts for the men, and dugouts for ammunition. These latter must contain the in- creased " iron ration " required for repelling an attack. The amount of this " iron ration " is shown in the following para- graph : 24. Ammunition. — Iron ration : Rounds. Field gun battery 2,000 Light field howitzer battery 1, 500 10-centimeter gun battery 1, 500 Heavy field howitzer battery 1, (KM) 21-centimeter mortar, each KM) German 12-centimeter gun battery j German 15-centimeter gun (Ringkanooe) battery 1 BOB Russian 15-centimeter gun battery J Belgium 8.7-centimeter gun, each 80 9-centimeter gun, each 190 In addition each field gun must be provided with 12 ease shot and each 9-centimeter gun with 5 case shot A guide to the construction of battery positions is given in the appendix (not received). 25. Battery positions. — I forbid any gun being placed in posi- tion in the first trench of the tirst-line position. Belgian 5.7- centimeter and 8.7-centimeter guns may be employed in the de- fense of the second-line or Intermediate positions, in excep- tional cases they may be employed to defend heavy batteries or the rearmost trenches of the tirst-line position. None of the other guns will be sited in advance of the Intermediate posi- tion. Every battery position will he protected against attacks at close quarters by a special wire entanglement. Hand gre- nades. 50 for each battery, will be kept in the battery position) 1 ! 87 in separate recesses. A supply of demolition explosives will be kept ready near the old guns for which there are no teams, and the personnel will be instructed in their use. If the enemy ad- vances and it is not possible to withdraw these guns, they will be destroyed. Should it be found impossible to destroy the ammunition, it will be rendered useless by unscrewing and re- moving the fuzes. In cases where the battery possesses only one of the topo- graphical section battery plans, it will be kept in the battery position. 26. Observation posts. — It is advisable for each battery to have at least two observation posts. Where conditions permit it, the main observation post will be close to the battery. All observation posts will be shell proof. The enemy's attention must not be attracted to observation posts by movement to and from them ; notice boards must be placed on paths leading to them, pointing out the necessity for proceeding with caution. Auxiliary observation posts will be situated in or close behind the infantry position. From them will be observed the fire of individual batteries on special targets, such as sectors of trench, trench mortars, and machine guns. The artillery liaison officer attached to the infantry must be at the infantry commander's battle headquarters or in its im- mediate vicinity. 27. Telephones. — Buried cables have proved very successful in the reserve corps. When crossing the open they are buried to a depth of at least 5f feet, and in trenches they are laid at least 1\ feet below the surface of the sole of the trench. When laying new lines, a greater depth is advisable (6i feet and 3 \ feet). Further, when cables are led into dugouts, command posts, etc.. they must be laid underground. The most important messages sent back from the front and to the artillery are " Barrage " and " Gas attack." The line will be cleared for them, and they will take priority over every other conversation. 28. Counter-battery work. — Our artillery is registered on all known artillery positions of the enemy, and each battery on every artillery target within range. Preparations for a hostile attack include the deployment and registration of a very large number of batteries. During this period the enemy's artillery must be constantly weakened by shelling individual battery po- sitions which are known for certain to be occupied ; the proce- dure should be based on the following principles: 88 Evidence of the battery position being occupied will be ob- tained by means of aeroplanes, captive balloons, or bearings taken by the survey sections. 29. Survey .sections. — The survey sections take bearin night on the flashes from the enemy's guns and report the results to the artillery commanders. Only cases in which three or four bearings are obtained will be taken into consideration. For purposes of observation by day the sector of the enemy's front will be divided into groups. The survey stations will observe which groups are firing, the number of rounds fired, and the targets. When a battery is registering by means of the artillery plan auxiliary points lying as nearly as possible in the line of fire will be selected, on which the survey sections will register. Fire will then be corrected in accordance with the measurements, on the plan, of the distance between the point registered and the target. 30. Balloons. — Registration by balloon can usually only be carried out in very clear weather and on a calm day. 31. Aeroplanes. — An aeroplane which is registering must be escorted whenever possible by a battle plane. This is quite feasible under present conditions, if the aeroplane keeps over our lines while registering, for it can then be protected by a Fokker. Over his own lines the enemy enjoys superiority over us by reason of the number and design of his battle planes. . A number of batteries, winch have been selected for bombard- ment, must be indicated to the aeroplane observer, l.attery commanders must arrange with the aeroplane observer before Ihey shoot with regard to target, tire procedure) and method of transmitting the results of observation. On a day previous to Hie shoot, the aeroplane observer must have flown over tbe batteries concerned in order to decide wbicb batteries are easily and which are not easily observed from the air. Registration will close when at least two groups or salvo* have been observed to fall correctly. Aeroplane observation will also be Continued during the first part of the fire for effect. Should tbe shots fall correctly at tin 4 beginning of this, the aeroplane observer has fulfilled his task and is free to return home. The battery commander must be told how long the aeroplane can tly over the enemy's battery (petrol capacity, outward and homeward flight). The survey stations must take bearings during the first portion of the fire 89 for effect, so that the tire may also be controlled after the departure of the aeroplane. The enemy's battery should be not merely silenced but de- stroyed. This will require about 150 rounds from a (15 centi- meter) heavy field howitzer or 100 rounds from a (21 centi- meter) mortar. As soon as possible after the shoot, the target should be photo- graphed from another aeroplane in order to ascertain its condi- tion and the effect of the rounds fired. 32. Method of engaging the enemy's infantry. — When an infan- try attack is threatening, intense artillery fire will be directed on the enemy's trenches (Corps Orders, la. 693, Secret, of 12/5/16, par. 7). When the assault is launched, barrage fire will be opened (Corps Orders, la. 693, Secret, of 12/5/16, par. 7). 33. Light signals. — Cartridges which produce a red light breaking into "pearls," will be used as a signal for barrage fire. Should our fire be too short and fall on our own trenches, the range must be increased. In this case cartridges which produce a green light breaking into "pearls," will be used. It is advisable, where the ground is suitable, to have observers in lookouts placed high up a'nd near the batteries, who can see the light signals sent up from the front line, in spite of smoke and clouds of gas. AH light-signal cartridges must be preserved from the damp as much as possible- (packed in wooden cases, etc. ) . These cartridges will be issued on the following scale : For the company furnishing the garrison of the trench and the supports, 100 red and 70 green. For each division for instructional purposes, 150 of each. As divisional reserve to replace unserviceable, 100 of each. Light signals are, however, only one of the signs used to de- note the necessity for opening barrage fire or for lifting artillery fire. The artillery should never delay in opening fire when the intensity of the enemy's artillery fire leads to the supposition that an attack is imminent. When the artillery fire in any particular sector is already fairly heavy, the right moment may easily be missed. In such cases the artillery, so far from wait- ing for light signals or telephone messages from the infantry (both means of communication may fail), should shell the en- emy's trenches with an intensity increasing in proportion to the enemy's fire, in order to prevent his infantry from leaving its trenches. Immediately it becomes evident from the enemy's 90 artillery fire at what point he intends to break through the fire of every battery, with the exception of the (-1 centimeter t mortars, will be directed onto the portion of the enemy's front- line trench which is opposite the sector threatened. Battery commanders have necessarily to act on their own initiative in this matter. The (21 centimeter) mortars will shell the enemy's assembly trenches, which have been previously located. Should the enemy launch an assault, barrage tire will be opened. 34. Practice in fire control. — The rapid concentration of fire on the enemy's points of assembly is difficult to achieve and must be most carefully practiced in every detail. Divisional artillery commanders will test the smooth working of the meth- ods of indication of targets and transmission of orders by car- rying out fire-control drill. This should be based on the various possible schemes of attack. The various distributions of fire will be noted in the fire-distribution books of the batteries. As a check, each battery engaged will fire a round at its allotted sector. Every possible contingency will be dealt with at fire- control drill. Divisions will cooperate with this object. The senior artillery commander will direct the fire-control drill when practicing against sectors requiring the cooperation of the artillery of two divisions. Fire-control drills must be treated from a tactical point of view. Information of the enemy's movements may suddenly reach the rear from the front line or t he signals may be observed in rear. The limits of the artillery sectors correspond more or less to those of divisions. In a divisional area the artillery fire control is in the hands of the artillery commander. The latter directs the artillery groups, which are usually composed of field and heavy guns. (Signed) v. Stkin, (General Officer ('ommundino. MEMORADUM. TO BE GIVEN WITH ATTACHED LETTER TO ALL PILOTS AND OBSERVERS IN SECOND BRIGADE, ROYAL FLYING CORPS. It is a matter of common knowledge and comment that, since the war began, measures for the purpose of denying the enemy information about our military and naval operations have be- come more stringent and numerous as the necessity to obtain it has become more urgent and vital to him. The magnitude and issues of the war seem almost too vast for one man to contemplate, and to this is due, in all prob- ability, the continued indiscretions of officers and men in dis- closing information, for they find it hard to believe how many details learned by the enemy of the movement and, location of an individual man or unit can in any way affect the result of operations and consequent duration of the war. They fail to realize that, although one such instance as an isolated fact would not, in all probability, be of as much value to the German great general staff, yet the ramifications of the enemy's intelli- gence system are purposely wide in order to collect such small details, and "on dits," the accumulations of which enable hypotheses to be verified and deductions to be confirmed. The average flying corps pilot or observer has great oppor- tunities of knowing the program of operations, the disposition of troops, and the material available not only of the royal flying corps but of the corps and army with which he is working. This knowledge is a sine qua non of his work. The enemy knows this well, and hence the capture of a pilot or observer is an oppor- tunity for obtaining information which he spares himself no pains to take advantage of without scruple as to the method he employs or the trouble he spends. What is written on attached is in the form of an open letter addressed to every pilot and observer in the second brigade, in the hope that he will bring himself to realize that he may be placed one day in circumstances where personal honor will make it incumbent on him to act in a manner which discipline would be powerless to enforce. (91) 92 OPEN LETTER TO OFFICERS AM) PILOTS OF THE SECOND BRIGADE. If you are unfortunate enough to be compelled to land behind the German lines you may be agreeably surprised by the appar- ent hospitality and generosity of your welcome there. The Ger- man officers will probably have you to stay with them as their guest for a few days at one of their squadrons, and will make you most comfortable. You will probably be extremely well entertained with the very best of everything they can offer. An abundance of good champagne from France will oil the wheels of conversation between the officers of the German Flying Corps and one whom they will probably term a brother officer of the English Flying Corps. They will appear to be very good fellows — straightforward, cheerful, and keen on the scientific side of flying, apart from their ordinary work, with which they may say they are quite fed up. They will probably lead you to talk about the possibilities of aviation after the war, and profess little interest in aviation as actually applied to the war. It may not take much wine to gladden your heart, and to induce you to lay aside your suspicions and reserve, and forget the guile which lies behind their artless questions. And so, unaccustomed as you are to this form of deceit, you may fall another victim to this clever combination of cunning and hospitality. But though they may succeed for the moment in making a favorable impression, you will afterwards have every reason to remember that during this war the Germans have proved themselves to be a cruel and unscrupulous enemy. but they are sound financiers, and have an eye to good invest- ment. It does not cost them much to entertain you well, and even if it did, they expect to get an adequate return for their money in the form of information unwittingly imparted by you. That is why they will give you all the delights of the "Carl ton 7 and " Savoy " with none of the regrets of an overdraft at Cox's, and that is why you will be treated as an honored guest. instead of being half starved in one of their now notorious prison camps; a treatment which is in fact only postponed until they have squeezed every ounce of useful information out of you. The work is done by experienced men. Quite unknown to yourself, one or more of the seemingly irresponsible Hying men ;ire highly trained intelligence Officers, who will sift hits of useful information from your most brilliant " b<>n mots"" received with the keenest amusement and gratification. 93 On the other hand, different methods may be employed, though these are not so common with prisoners of the flying corps as with others. You may be browbeaten and ordered to disclose information on the pain of suffering severe penalties if you refuse. Remember this is only a ruse, and that they will not carry out their threats. It is more probable that they will respect you for your patriotism and discretion. It is quite possible that you may be placed in a hut with an officer alleged to be an English prisoner, speaking English fluently, and knowing many people in England well, and wish ing to have news of everyone and everything; or perhaps he will ask no questions, relying only on your confidences. It will be difficult for you to believe that he is not a companion in mis- fortune, but this is a. common trick of all intelligence services, and a very profitable one. Therefore be on your guard, and remember that in a show like this it is impossible for any individual not at the head of affairs to say what is of use to the enemy and what is not. Re- member that any information you may inadvertently give may lengthen the war and keep you longer in Germany ; may cost the lives of many Englishmen; may strain the country's resources even more than they are being strained at present. Don't think this is all imagination and needless caution. The need of it has been bought by experience. No careless or irresponsible feelings ought to weigh with us against anything we can do to hasten the conclusion of the war. HINTS ON RECONNAISSANCE FOR MINES AND LAND MINES IN THE AREA EVACUATED BY THE GERMANS. (Compiled chiefly from notes forwarded by Inspector of Mines.) The greatest care must be taken when reconnoitering ground evacuated by the Germans for mines and land mines. A cursory examination is not sufficient, as the mines are often extremely well concealed. The following suggestions, compiled from various sources, may be of use to officers making these reconnaissances : CROSSROADS. Crossroads are often mined and the charges have been known to explode as long as 48 days after our occupation. The surface of the road should be carefully examined for signs of fresh work. Any found should be at once opened out to insure that there is no contact mine there. ( Sketches of typical examples — Nos. 1, 2, 3.) The ground should be cleared for 25 yards in every direction from the crossroads and carefully inspected for signs of the entrance to any gallery which may pass under the road. The entrance may be blown in or covered in by the debris from another explosion after the charge has been laid. Any small craters should, therefore, be carefully investigated. The following examples have been found : 1. In Noyon galleries had been driven from under the paving stones. 2. Gallery driven under road and excavated till only a thin crust remained ; 8-inch shell in position with the fuze portion on but loose and in contact with the roof. 3. Shell holes on a road, apparently filled up with bricks, etc., have been found to contain land mines fitted with instantaneous fuze and friction fuze lighter, with safety pin attached to trip wire (which had broken off). (95) 96 DUGOUTS. Any dugouts left undestroyed should be carefully examined. Look for any sols from which the tomms have been cut and replaced by wedges. Loose boards in floor, sides, or roof often locate the smaller variety of charges. Apparent dead ends should always be inspected carefully ; the two biggest charges were found behind such places, complete even to the pick marks one would naturally expect. Every alternate set should be removed and replaced. The following examples of what have been found may serve as a guide to what may be expected : 1. Grenades liable to explode when trodden on. 2. Dozen stick bombs, arranged to be fired by wire attached to sandbag which had to be removed to open a dugout floor. 3. Wires to fire charge attached to handrail in entrance of dugout. (In dugouts constructed with casing, mortise, and tenon joints the position of a charge is sometimes indicated by the wedging of the timber, where sides have been cut and re- moved.) 4. Charges of 2,000 pounds with 20 feet of tamping in wall of dugout connected with a pair of fire leads amongst a number of telephone wires. (Intended method of fire not discovered.) 5. In two cases charges of a few hundred pounds left in un- damaged dugouts, which were attractively equipped so as to Induce early occupation, exploded about eight days after enemy evacuation, presumably by clockwork or other delay-action device. 6. A shovel stuck in the side of a dugout between timbers. The wires from battery of three dry cells were one attached to metal and the other to contact plate. The shovel stack out as an obstruction and would in the ordinary way have been re- moved. 7. A false step in the stairway of dugout of thin planking -nuk- ing contact when trodden on. 8. A blown-in entrance to a dugOUJ is not always a safety simi. Charges may he concealed in the unblown portion, They are generally crudely arranged contact charges, 9. An elaborate and neat trap has been discovered under the Achiet-le-Grand-Bapaume Railway embankment, southeast of 07 Bihucourt, Above the timber ceiling of a tunneled stairway leading to dugouts under the embankment was a mine, to which access was obtainable only by removing three of the setts (frames) of the stairway. Every sett was intact and carefully wedged, there were no gaps, and the hand rails were continuous. (Sketch 4.) 10. A window weight, suspended by a fine cord crossing en- trance, arranged to drop into a box of detonators in connection with charge. 11. One of the pieces of timber on the side of the stairs leading down into a dugout projected slightly inward at the top, though it was in place at the bottom. It was pulled out for investiga- tion, and a nail was found driven through its lower end, the point of which was placed against the cap of a cartridge which had a charge of explosive behind it. Had the plank been forced into its correct position, the nail would have struck the cap and exploded the charge. 12. Branch placed over entrance to dugout as if to conceal it, when removed caused an explosion 2 minutes later, completely destroying dugout. 13. Trip wires in entrances of dugouts, etc., arranged to ex- plode charges or grenades. 14. Charges have been found in chambers on each side of the entrance, in chambers off the dugout itself, in the ventilating shafts. 15. Charges are usually found to be 80 to 150 pounds of Perdit placed in small chambers at a height of 5 feet from the floor, and in the ventilating shafts 10 feet or 11 feet below ground level, and in every case at the end of a little gallery 4 feet long by 18 inches square. The charge is tamped with a wooden panel, backed by loose stones cemented over at the end. Firing is elec- tric by armored cable. HOUSES. A house of any size left standing should always be looked upon with suspicion. The cellar especially should be carefully examined and the surface inspected and ground around the house cleared of debris, as mines are sometimes sunk against the wall of cellar. The following examples have been found : 1. A box of explosives buried in a cellar, timed to go off by the corrosive action of acid on a steel wire. (Sketch 7.) 9784°— 17 7 98 2. Charges, with fuse and detonator, in chimney. 8. Detonators in lumps of coal. 4. Book on table, with wire down leg of table. Charge would fire if book were lifted. 5. A mechanical fuse igniter attached by wire to an explosive charge fixed in the walls of a house has been found in Neuville- Bourjonval. 6. In the paving of a house in Roye the Germans had sunk a hole from the ground floor to a stone drain 5 meters below the ground level ; under this drain there was a concealed shallow well ; from this they had driven out two small galleries and charged them each with 150 pounds Perdit. The hole to the drain had been filled in again and repaved. 7. The French experimented successfully for clockwork de- vices by means of the geophone. 8. Grenade under loose brick in floor of stable covered with straw. Pressure on brick would explode grenade. RAILWAYS. Especial care should be taken with the investigation of the following places for signs of enemy work : Bridges. — Charges are often placed on the girders, or holes are sunk in the abutments behind the girders. The approaches to a bridge which has been destroyed should be examined. Trap charges have been discovered which were laid with a view of destroying the temporary structure over the gap. Level crossings. — In some cases mines have been driven under the crossing by means of an inclined gallery from the think. Embankments. — Charges have been discovered at the ends of galleries, driven into the embankment. A land mine was dis- covered fixed inside a rectangular box 8-inch by 8-inch see tion, 10 feet long. This box was sunk vertically in the em banUment between the rails. One foot of earth was rammed in on top of the explosive, which was to be fired by electrical means. WKIX8. Wells are often destroyed by boring a 6-inch hole, 10 to 'J' 1 feet deep, a few feet to 0WB s hle of the well, filling this with explosive, and blowing It. (Sketches Q ami 6.) The following tips for locating wells blown in this manner may be of use ; 99 1. The German sign for a well is a white board bearing a red ring with a red disk in center, or the word " Briinnen." 2. The locality of a well is usually a crater in the yard of a building. The charges are usually placed about 12 feet from side of well, 10 to 20 feet deep, so that the well is never in the center of crater. 3. Men employed reclaiming a well should work with a life line on. Novita sets should be handy in case of any men be- coming gassed from fumes of explosive which was burnt. 4. Wells and ponds have been rendered unfit for drinking by means of creosol, dung, and all sorts of filth. Wells should be labeled " Not to be used " until the water has been tested by the local expert. BATHING PLACES. Pointed stakes have been found driven in with their points below water level and interlaced with barbed wire. Bathing places should be examined before being taken into use by the troops. GENERAL. The following remarks may be useful as regards the search for and destruction of an enemy's land mines. Great skill and care are required. Suspected localities should, first of all, be- studied with good field glasses. The following signs should be looked for : Freshly turned-up earth, settlement of the ground, oval marks on the ground after rain, patches of grass that stand out conspicuously, narrow strips w T here the earth has been disturbed which may mark where leads have been laid, ends of wire, cord, and canvas sticking up, numerous foot tracks on a confined space, litter of materials, such as powder, guncot- ton, shavings, paper. Suspicious places in soft ground can be investigated with a probe. If a contact mine is discovered, it should be marked and destroyed later by firing a slab of gun- cotton on top of it. Trip-wire mines can be destroyed by at- taching a guncotton primer to the wire and detonating it or by firing the mine by means of a long cord made fast to the trip wire. When the leads of observation mines are discovered they should be cut singly and the ends turned up. Contact mines have sometimes been exploded by driving cattle over them. The following devices have also been discovered: 1. Barricades interlaced with wires attached to stick bombs. 2. Hand bombs buried in trench with telephone wires attached. 100 3. Trench boards, new in every case, on several Are steps, which detonated bombs when trodden on. 4. Seven-inch shells with fuze removed and replaced by det- onator. 5. Cap badges, artificial flowers, bits of evergreen, pieces of shell, and other articles likely to be picked up as " souvenirs " attached to charges. 6. The preparations for blowing up Fort de Conde appear to have involved charges of 2,600 to 3,000 pounds, to be fired inde- pendently after the fort was captured. The electric lends were duplicated, one being apparent and the other buried 1$ to 2 feet below it. EXPLOSIVES. The explosives used by the Germans are Westphalite, Perdit, and Donarit. They are all hygroscopic. Charges found by the troops may, therefore, be rendered reasonably safe, in the first instance, by being saturated with water. They should be left in situ to be removed by men accustomed to handle explosives. The withdrawal of charges must be done with care, as detona- tors are frequently found distributed throughout them. This is specially the case with portable charges made up in tins. Deto- nators have been found in the middle packets of one of these. Each charge should be opened for examination. Exploration for charges leads to the accumulation of a forge amount of loose explosive, Which is unfit to return to store. This should be destroyed as soon as possible in one of the fol- lowing ways : 1. By detonating it in small quantities, in consultation with troops in the vicinity. 2. By scattering it broadcast &ver w;iste ground. It Should be remembered that if the ground is subsequently occupied In- animate as picket lines they run some risk of being poisoned. 3. By burning, the explosive being laid out in long parallel lines about 6 inches high. This is the beet and safest \v;iy. provided all detonators have beea removed. The fames are un- pleasant, and the explosive should he burnt after consultation with the troops in the neighborhood, and carried out When the wind is in the direction which will cause least inconvenience. 4. Ignition of the explosive is facilitated by mixing with it a little cordite or the charge of German howitzers. Charges must not be destroyed by throwing them into ponds or down wells. 101, SKtTCH N?7 GERMAN AUTOMATIC DETONATING DEVICE UJED IN CONNECTION WITH EXPLOSIVE CHARGEJ LEFT IN DUC-OUTJ, BILLET* & ELJBWHgRE. Copper Ming " — Ca P » -r"~i[s Y<\ 1 1 h^. i Lrf n J C*<3owc*ff / post a man in our front line, opposite the point where our patrol is working, with Instructions to Ore 1J- inch Very llglltfl at tixe.l finite. s:iy. every ."> minutes, after the first 46 minutes. During this tirst three-quarters of an hour" no lights should be fired, as the patrol is getting into position 117 to observe. When the time comes for the flare to be fired the entire patrol must be in shell holes and no one allowed to look out except the officer and noncommissioned officer. One should look to the right and one to the left and conceal themselves as described under crater investigation. It is necessary that the Officer's watch and that of the man firing the flares should be exactly the same and that an understanding be reached that if the first flare is a dud a second or third be fired at once, the time for the next being reckoned as if the first had not failed. The light must be fired high and go over the heads of the patrol. On no account must it fall behind them, as this would throw them into relief and be fatal. A light dropping just in front of the enemy front line blinds him and shows up the wire very plainly to the patrol. If the light goes over the enemy trench it does not blind him, but still shows up the wire during its fall. The best time to observe is while the light is still in the air and before it has passed over the enemy front line. During this time it is shining in the faces of the enemy and from behind the patrol, whose eyes are not blinded. After it has struck the ground it often shows up the heads of the enemy sentinels and some idea of how he holds his line may be determined. These lights are of great assistance but are dangerous and can only be used after making certain that the man doing the firing knows his instructions. While the patrol is out no other flares must be fired anywhere near where they are working, or any at all, if it can possibly be helped. Usually the most dangerous kind of a flare is one fired way off to one flank, maybe half a mile away. Always be quiet when a flare goes up, no matter how far away it is. Warning. — Although patrols are more or less independent, there must always be perfect cooperation between them, the infantry, and the artillery. Every afternoon the scout officer should make it a point to see the officers commanding battalion and all company com- manders to determine whether, they desire anything particular done, and if not, to tell them what the plans are for the patrol during that night. If the companies are going to send out wiring parties they have a right to expect that the scout officer furnishes leaders for the covering parties. No matter what kind of work the companies intend to do in front of the parapet, the scout officer must be notified beforehand. He is absolute officer commander of " No Man's Land," and no man, from the 118 battalion commander down, has the righl to Step over the para- llel without notifying him. One man must ho in charge Of " ]No Man's Land," and the scout officer is the logical man for the position. If any officer can go roaming around our wire he will he killed sooner or later by our own patrols or kill some of the pfttrols. A large number of casualties have been caused in this manner, for a man out In " No Man's Land " can not stop to ask questions, and if anyone is seen when no warning has been given ho is presumably an enemy. Conversely it is just as important that the scout officer notify all parties concerned before any of his men go out. It is not sufficient to simply notify the company commanders in the afternoon that a patrol is going out. Every man on the front affected, the battalion on the Hank, aiid the trench mortar and artillery liaison officer must be given the following facts: (a) Time of departure. (b) Place of departure, (c) Size of patrol. (d) (Ground to be covered, (c) Time of return. (/) Place of return. ( possible so as to giVfl them some experience in " No Man's Land.'* The confidence thus gained COfneS in very useful when the men are sent on wiring parlies or when they - go ever the top" in an otTensive. Company pahols rlt automatic. If care is taken, no mud gets into the working parts, and the rapidity of action and reloading offset the disadvantages. In tiring at night so many shots una wasted in misses that quick reloading is essen- tial. Two Mill's bombs, carried in the hip pockets, is about all that can be carried with any comfort. All members of the patrol should be equipped with rubber suits that tie around the ankles and wrists and lace up the hack. They must not fasten in front, as the strings would get tangled in hits of broken wire on the ground, and the opening let in the mud. The material is soft and does not rustle. Before going out each man should -roll in the wet mud, for the mud from the previous night lias dried and is of much lighter color than the wet mud. Hands and faces should also be covered with mud and also the outside of revolvers, if it is a moonlight night and the gun metal glistens. A very important thing is to have each man carry gum or pep-, permint to use in case he has to cough. Most scouts have colds due to being wet every night, and the strain of patrol ing breeds a desire to cough that it is impossible to overcome. A cough close to the enemy means certain detection. All forms of identification must be removed from scouts, such as identity disks, patches, regimental buttons, cap. collar, and shoulder badges, pay books, and all letters. No article of cloth- ing or equipment can have the battalion number on it, for even a handkerchief, with the number on it, if it is captured, gives all the information that a successful raid gives. Patrol formation*. — There are a large number of different formations, but the best for general purposes is the - wedge formation." The main advantage of the "wedge formation n is that it ban be formed into a defensive formation facing any direction in the shortest possible time. The best defensive formation for bomb- ing of this nature is a line facing the enemy ; first you have all your men in action ; second, it is the most ditlicult target. The drawings explain themselves. The otlicer simply calls out which formation to take, and then orders an advance or retreat according to circumstances. It is often advisable to take a man from one of the Hanks of the wedge and have him follow in rear to prevent surprise from that direction. If any enemy patrol is met. the best policy is to form line facing them, lire one bomb apiece, and rush after your bombs 121 ft a. •1* o--° « £ s^ w> o- . --- | ? 0- ' p '? ? I If 0 ^ * o ^ i £ r* 122 have exploded. The enemy bombs are nearly always time bombs, and by rushing in close with revolvers you usually pass or leave their bombs before they explode. Another advantage of a quick rush is that If any of the enemy have been wounded or killed their comrades will not have time to remove them and Important Identifications may be secured. As a rule, a German patrol will not face a discharge of Mills bombs and a determined rush of even half their number. Th e re Is little danger at 2 yards From a German u potato m.isher." while it is nearly certain death to be standing 12 yards from a Mills bomb. Immediately on throwing the Mills the patrol should lie down and start revolver fire until the bombs have exploded. To he standing is to court danger from our own bombs, which may kill at 100 yards. Method of (uawling. — It is difficult to describe the way to crawl without giving a demonstration. It is not necessary to get down and crawl until within 125 yards of the enemy lines, unless it is a very bright night or an unusual number of lights are being fired. To do so wastes too much time and needlessly tires the men. Up to within this distance the patrol can move by crouching or on its hands and knees. After passing the 100- yard mark, Increasing care mast be taken until when within 15 or 20 yards, when movement is only possible by inches. Only highly trained men can hope to escape detection at this distance. When crawling the main thing to avoid is any sudden move- ment or the showing of any outline of the head or shoulders. The body should never be raised a particle from the ground so as to let any light between the two. For the same reason it is neces- sary to be very careful not to allow the bent elbows or the feet to leave the ground. The legs should be kept as close together as possible, and the arms not allowed t<> be spread out any more than necessary. Before starting to crawl the caps should be turned around with the visors to the rear. There are two reasons for this; first, that with the visor in front it is impos- sible to get the face close enough to the ground, and. second, that it gives the German appearance to the head. For the latter reason the caps must be turned around again before entering our own lines. When on the move never lift the head to see where you are going. The face must be touching the ground. If it is absolutely necessary to look. Wep one cheek on the ground while doing it and use just oue eye. 123 When a light goes up every man must remain absolutely still, no matter in what position he is in. Even if he is standing up in the enemy's wire, the chances are that he will not be seen if he doesn't make a move. It is instinctive to take cover when in snch a position, but it is certain death to move even an arm. While a light is up it is harder to see a still object than when there is no light, because there are so many shadows thrown that a man may be easily mistaken for one. If while you are in a badly exposed position a machine gun opens, it is natural to think that it is firing at you. and the desire for cover is almost irresistible, but the chances are that you are not being tired at, and if you remain cool and quiet you will escape unhurt. This is one reason that it takes long training to make a good scout. Without practice hardly any officer or man can stand up in ap- parently plain view of the enemy without crouching slightly. and that is sufficient to give the [tarty away. As soon as seen, lights are sent up and kept in the air to hold you to your position, and then machine guns and bombs com- mence their work. The instant a patrol is certain it is discovered it must get out of bomb range. It is always a few moments before the Germans can bring their machine guns to bear and get bombs off. During those few moments the patrol must get out of bomb range and into shell holes, where they must stay until the excitement is over. When things quiet down a bit. don't move at once, for often the machine guns open again suddenly in the hope that the patrol has done that very thing. During the initial retreat there will most likely be a rapid rifle tire going on, but that must be risked, and is usually not very effective at night. Capture of isolated posts. — There is very little to be said on this subject, except that it is a very difficult and dangerous piece of work. The capture must be made without any noise, for if the main trench is alarmed lights go up. and you are held in the advanced post and bombed out at leisure. The only time when this kind of thing is practicable is when there is no wire around the sap leading back to the front line, and you can slip up the sap into the post. It is almost impossible to approach close enough above ground to force a surrender without a bomb being thrown or the alarm given. In most cases it is simpler to chance hitting a post and endeavor to enter the front line and then re- main hidden behind a traverse until some one comes along, and put a gun in his back. If discovered and alone or with one man. 124 try to get over the parados and hide there. The enemy will not expect you there. If a party is with you, make a rush foj? " No Man's Land." Some may escape* These stealth raids have censed to be a success lately, as after a year's experience the Germane are beginning to he more alert. The only pra. Zone and height of flight. — The zone and height of flight are matters for the observer. He must fly in such a manner as to be able to carry out his instructions, and must bear the follow- ing in mind: (a) The higher and the farther away he flies, the more uncertain becomes communication with the battery that is firing, and the best observation becomes worthless if communication breaks down. This applies principally to ground signals, but it is also true for communication by wireless. (b) Errors during observation will be most easily avoided if the observer flies approximately over the line of fire. (c) In order not to disturb ranging by wireless in neighboring sectors, the observer must fly within a limited area during observation. 7. Protective aeroplanes and protection by antiaircraft guns. — Protection by means of special aircraft is necessary, when attacks by enemy aeroplanes are to be expected. Antiaircraft- gun protection is desirable. Warning rounds from the anti- aircraft guns against the enemy's aeroplanes are of great value. 8. Method of observing fire — (a) Indication of target. — When a target lias to he described from the aeroplane (see IV, B. 2), it can be done : 1. By means of the- map squares or battery numbers in the artillery map, or 134 2. By means of the target's position relative to a refer- ence point (see Appendix 1). Wireless "in clear" is only to be used in the most exceptional cases. (b) Registration and battery fire. — Rounds with percussion fuze are the general rule. It is important for the very first rounds, if possible, to be seen by the observer. Should single rounds be difficult to see, then ranging will be done by section salvos or battery salvos. This will be ordered beforehand (see B. 2 e), but can also be asked for by the observer during the flight. The method of signaling the rounds in ordinary fire is with correction by deflection and by short or over (+, — , r, 1.) (see Appendix 1). The observer reports first the correction for de- flection and then for short or over. The amount Of the short or over correction is only to be given in the case of the first few rounds observed. The supposition that quicker results would be obtained by giying the correction in meters sent by the aero- plane to the guns direct than by orthodox ranging by bracket and battery fire has proved to be wrong. The constant zone of dispersion of our guns makes it necessary that the well-founded principles of our gunnery regulations should always be adhered to. During ranging and battery fire all rounds are to he ob- served and reported by the observer one by one. When ranging special guns, the method of reporting remits of rounds given in Appendix 1, No. 4 (b), may he used. (c) Fire for effect. — The opening of fire for effect is decided by the battery commander (ground signals, see Appendix 1). From then onward the battery tires without being asked to do so by the observer; the latter should only report now and again the fall of a number of consecutive rounds (about 6 to 12), Tf some of the rounds are noticeably short or over, or fall very much to a flank, then the observer again asks for single rounds and again corrects for each round. It is desirable that important cases of tire for effect should be observed to the finish, as the error of the day often causes con- siderable changes in trajectory in quite a short time, making all shooting worthless unless these changes are observed and re- ported. As. however, it is not always possible for the aeroplane to fly so long, and as one flight must often he used for Several consecutive shoots, one must often be satistied with observing only a pari of the tire for effect. In such a case the tire for 135 effect can occasionally be continued with advantage by other means of observation (captive balloon, survey sections), if the latter have also been observing since the beginning of the shoot. It is a matter of principle that they may not, during registration by aeroplane, take part in reporting results of rounds. (d) Photographing after fire, — After fire for effect a photo- graph of the target is to be taken ; that is, if the vicinity of the target has not been too badly shot about by previous bombard- ments, and if it is supposed, from the amount of ammunition used, that the results will be seen on the photographs. (e) Ranging several batteries. — Ranging several batteries simultaneously by one aeroplane is forbidden, as this generally leads to errors and consequently to waste of ammunition. On the other hand, it is simply a question of time and practice, and of the artillery and aeroplanes working together well, for an aeroplane to range several batteries on different targets one after the other. V. Training at the Front. Every artillery shoot must, as far as possible, especially on quiet fronts, be used for training purposes. Ranging purely for training purposes can usefully be carried out with quite a small expenditure of ammunition. VI. Trench Mortar Shoots. Aeroplane observation for trench mortars can be carried out in the same way as artillery registration, and the above direc- tions will still hold good. APPENDIX 1. I. CODE SIGNALS. 1. Instructions for the use of wireless : (a) Every wireless message will be transmitted on the mini- mum power necessary for communication. The speed of " send- ing " will be as quick as possible. (h) The following procedure will be used when establishing wireless communication : (1) Call. Station call of receiver from station call of gender. (2) Message. (3) "End of message" or "change over" signal ( Umschaltezeichen ) . 136 (c) After communication has been established the following procedure will be adopted : (1) Station call of the receiving station. (2) Message. (3) Station call of the sending station or "change .over " signal. (d) A wireless message, if of considerable length, will be pre- ceded and followed by a " break " signal. (e) All wireless stations and aeroplanes are allotted wireless calls of two letters each. (/) These wireless calls will be so chosen that they <1«> not coincide with any abbreviations under paragraph 2. 2. Abbreviations: 1 (a) WIRELESS SIGNALS. Abbrevia- tion. Genua. English equivalent. S Schuss Hound (shot). SA Salve Salvo. EF Einzelfeuer Single rounds. Sz 1st geschossen worden? Es wurde nicht geschossen. . Feuerbereit Has battery fired? N6 FF No firing has taken place. Ready to fire. DD OU WBS Schiessen beendet Beobachtung unmogUcfa Welche batterie steht zur verfugung? End of shoot (for intercommunication between two stations this moans: The station will close down). Observation impossible. Which battery is at my disposal? (6) SIGNALS FOR RANGING. z Ziel Target. i out it of target. Right of target. ! eft of target. Over. Short. Right. left. Target, hit. Proposal for change of target. Not observed. Doubtful. ZM Zielmitte ZR Ziel rechts ZL Ziel links W Weit K .. R L Links . TR Trailer NZ NO Vorschlag sum slerwechsel . . Nicht beobachtet FR. Fraglich (c) DESCRIPTION OF TAl: IM IV Infanterle in manobkolonnc [nfanterfe in versammlung. . Artillerie in marschJcoIonne . Infantry in column of route. infantry concentrating. AM AF Artillery in column of route. Artillery in action. M\V BV AT EV. Marsehkolonne aller walfen. Bagagen in versammhmg. . Ausladung von trapper*. Column' of all arms on the march. A collection of transport. Troops detraining. Railway traffic. 1 The abbreviations given here are for general OS they must be arranged beforehand. If additional ones are n eede d . 137 (d) PHYSICAL FEATURES. Abbrevia- tion. German. English equivalent. GB. Graben Trench. PT. Punkt Point, ED.. . Eisenbahndamm Railway embankment. Wood. WD .. Wald STR... Road. («) GENERAL ABBREVIATIONS. PA NH MR . Planquadrat Fliege nach Flughafen Map square. Am coming in. Engine trouble. Must land. Clouds. Mist. To the North. To the South. To the East. To the West. SOS Muss notlanden WO Wolken DU... Dunst NL Nordlich SL Sudlich OL.. . Ostlich WL.... Westlich (/) ABBREVIATIONS FOR WIRELESS COMMUNICATION. UM, UM. "Change over" signal. Understood. VE .. Verstanden NV Nicht verstanden Not understood. US BP Storungenim Funkenbetrieb. Wireless is being jammed. I am expecting your message. Wait (Message will be continued imme- diately). Wait ! I will call again in five minutes time. Principal wave length. Wave length for mist, More power. Less power. Nothing further. Message deciphered. There is an enemy jamming station here. Repeat. How are you receiving my signal . Message received from you does not make sense. Cipher message. Message in wireless service cipher. End of message. At least 10 dots in succession = erase. AS. WA (5).. HH Warten NN.. Nebelwelle MG.. Mehr Energie WG... Weniger Energie NF FO Hier liegt kein Funkspruch vor FS WH WPG.... OS CHI ZIF AR Wie ist dort der Empfang? . . . Das Empfangene ist ohne Sinn Chiffrierter Funkspruch ChifTrierte Stationsnachricht . . Schlusszeichen Given as MV in the original, but this is apparently a misprint.— G. S. I. 13ft II. GROUND SIGNALS. The ground signals for signaling from the ground to aero- planes consist of from one to three variously placed strips of cloth (each 3 to 4 meters long, usually white, hut red when snow is on the ground). No of Grouod Si(oaJ Form MrMNtfl .Rrrotrki 1 V Understood" % = ^ Battery is ready to fire. If signal is taken away this means that the observation is ended 3 Battery is for the moment not ready to fire. 4 V Not understood repeat message 5 + Yes C N No 7 4= Battery is changing target as requested 8 u Battery is now going to fire for«effect 9 H Battery is going to fire single rounds again. 139 III. METHODS OF INDICATING TARGETS. (a) Indication by means of map squares or battery numbers. (&) Indication by means of a given reference point. 200 m. (Charley. ( 8 North. ( ( 2 West. IV. METHOD OF SIGNALING THE RESULTS OF A SHOOT. (a) Reporting the burst according to lateral situation and range. Abbrevi- ation. English equivalent. Remarks. L R z Left of the line battery— target Right of the line battery- target. Lateral corrections are given in figures so long as the bursts are outside the target. ZL. In target, to the left ZR W K In target, to the right Over, i. e., behind target Short, i. e., in frotat of target. . Corrections in range are given in figures only for the first few rounds. Examples : Burst 250 meters to right of target and 450 meters in front of it. Message : B 3 K 5. Burst 100 meters to right, about 50 meters in front of target. Message: R1K. Burst right side of target, about 50 meters over. Message : ZRW. Burst in center of target, direct hit. Message: ZMTR. 140 (&) When ranging special guns it may be preferable to take a photograph of the target or, in exceptional cases, a map. and to mark this as follows: The bursts will be signaled according to the squares. Every shot will be marked on the photograph. This will form a dia- gram of the rounds near the target and will in many cases replace the usual photograph normally taken subsequently. Extract from Appendix 2. 1. This appendix consists of a diagram showing on the TSTsjfjf sc.-ile the 100 per cent zones of the following guns and howitzers at various ranges and with various charges: 1.1 cm. heavy field howitzer ('02 and '13). 21cm. mortar. 10 cm. gun ('04). 141 2. The following is an example taken from this table : 15 cm. heavy field howitzer ('02 and '13). Range, 7,000 meters. Sixth charge. Time of flight 100 per cent zones Scale TT ^ B . . - - . A. For single gun firing at a single point (x) 30 seconds. 7~\ B . For a battery firing against a hostile battery with a frontage of 100 meters X l'2*?i ,pin 142 o *-> 15 c bo 'to CD S w 49 JD 5 CO •< J3 u «a 5S O 3 pC 55 CO 3 4) X .c z «a a *- CO X I GO ., Q w V £ S - 1 04 C3 - - o CD a < X - s s CD CD if •— 2 ; J$ 5 "5 CQ c CO B a 3 CD c | GO o3 u ei H S § CQ CQ CD ■i-3 I c CO CD — 43 e I 3 T3 IS CD IS -5 eg £ c O cs CD o o 143 + a c3 •8 u © O o I I + > O C o CO 49 § B IP u £ 8 'wj s.s ;- — O C3 22 fee * -EL o ~ o 4^ o *•-< CO fcr> C O +1 — 5(3 J5 O C c3 c II > C II 5- o u > o II • o •1 o • -*3 tie c I M E o fl cy & o> ti © cc ad c

© o - 1 «H 5 s > © a ■P too © 32 £ £ ~ Part (5. COMMUNICATION BETWEEN INFANTRY AND AERO- PLANES OR CAPTIVE BALLOONS. (Issued by the Chief of the General Staff of the Field Army.) I. Infantry Aeroplanes. 1. IMPORTANCE OF THE INFANTRY AEROPLANE SKKVHK. It is of the greatest importance for commanders and the artil- lery to have constant information, in the course of a battle, ;is to the progress of the infantry fighting, the position of the foremost infantry lines, and any of the enemy's measures which may have been detected. In consequence of the increased effectiveness of artillery tire, transmission of information from the front line to the rear, in spite of the increase of and improvements in the means of ground communication, is becoming more and more difficult. For this reason the infantry, when heavily engaged, is often unable to obtain the requisite effective support from the higher command and the artillery, ground which has been gained with difficulty lias been lost again, and the enemy's successes are liable to ac- quire a dangerous extension. In many cases the infantry aeroplane (contact patrol) can render valuable services to the infantry in this respect. Plying at a low altitude, the airman is able to define With great accuracy, on the maps and by photography, the situation of the front lines as revealed to him by the signals of ihe troops, and can also, by means of preconcerted signs and signals (see Appendix), trans- mit reports from the infantry, and the results of his observation of the enemy's movements quickly and safely to the rear. Proper cooperation between infantry aeroplanes and the troops will thus (144) 145 provide the infantry with an additional means of reconnaissance and communication. 2. DUTIES OF THE INFANTRY AEROPLANE. (a) Determination of the intuition of our oicn front line. — The main duty of an infantry aeroplane, in every flight that is under- taken, is to determine and keep under observation the position of the front line. In any case communication must be established with the infantry by means of signals. Even if the front line has undergone no modifications, the consciousness of being in com- munication with the aeroplane strengthens the morale of the infantry. (b) Transmission of tactical reports from the front line and from battalion and regimental headquarters to the rear. — The heavier the lighting, whether in attack or defense, the greater becomes the dependence of the infantry upon the aeroplane for the transmission of its reports. By means of the arrangements for communicating with the infantry, the infantry aeroplane is able to transmit to the rear, in the shortest possible time, all reports of special importance as to the course of the action and the conditions in the front line. It is particularly important to forward immediately any requests of the infantry for barrage fire. (c) Tactical reconnaissance in the sphere of the infantry action. — Thorough familiarity with all details of his sector en- ables the infantry airman, in addition to his other duties, to carry out very detailed tactical reconnaissance. From observa- tion of the artillery fire upon the front line with regard to the fall of the rounds and the volume and general direction of the fire, as well as from observation of concentrations, movements, and bringing up of reserves in the enemy's trenches, the object and direction of hostile attacks can he recognized, and, by an immediate report, can be nipped in the bud. :'.. EM IM.OYMENT AND COMMAND OF INFANTRY AEROPLANES. On the principal fighting fronts special aeroplanes will be allotted to the infantry divisions as infantry aeroplanes. Their number will depend upon the nature of the fighting and their employment will be determined by the flight commander con- 0784°— 17 10 146 reined, who will receive his instructions from divisional bead- quarters. It may be found necessary, in order to enable the infantry aeroplanes to carry out their duties even in the face of hostile aerial activity, to assign special aircraft for their protection. Applications in this respect should be made to the commander of the aviation troops or to the .wing commander; 4. MEANS OF COMMUNICATION. A. Communication from thk Ground t<> the Aeroplank. (a) Cloth signals. — These cloths are colored white on one side and dark on the other (for use In snowy weather) : those used at battle headquarters are 2 feet 7 inches by 8 feet 2 inches, and those employed in the front line 2 feet 7 inches by S feet 3 inches. It is advisable to stiffen the narrow sides by wooden battens and to keep the cloths in cases as a protection against dirt. By placing the cloth signals, stretched to their fullest extent. about 55 yards apart, especially at salients and reentrants of the front line, its outline can be defined. To avoid attracting the enemy's attention they must be displayed from the slope of the trench which faces away from the enemy. They can be used in certain combinations to convey tactical information. (See Appendix.) As against the disadvantages arising out of the difficulty <>\' displaying the cloths under hostile fire and of the possibility of confusion being caused by their nonromoval must be set the fad that they are easily recognized from an aeroplane, can be un- mistakably reproduced in a photograph, and. when once ex- tended, obviate the necessity for continuous observation on the part of Hie aeroplane. (6) Signal lamps. — Signal lamps (infantry signaling appa- ratus and special aeroplane Hash lamps) are used lor sending certin flashlight signals to the aeroplane. Much practice is required for their operation: it is no simple matter for the aeroplane, when hampered by difficult flying condi- tions and the Incidents of the battle, lo take the Signals so sent This means of communication is. therefore, not so reliable : more- over, the messages can not be reproduced photographically. (c) Flares. — The front line can be outlined by means of white or red magnesium torches or fiares. The Hares or torches must 147 be lighted at the bottom of the trench or in shell craters, if pos- sible against a dark background and screened from the enemy. If much smoke is produced, they will attract the attention of the enemy, and must, therefore, only be used exceptionally by the troops in certain circumstances (attack). In the absence of smoke, they are difficult to see from an aeroplane, and can not be photographed. When used they must be arranged with a certain amount of regularity (groups of 2 or 3 flares or torches, distance between the groups 55 to 110 yards). Signaling from the front line must be confined to the display of cloth signals, flashes by signal lamps, and the use of flares. Cloth signals (see Appendix) and Morse signals (see Ap- pendix) on the signal lamp can only be used for the conveyance of information from points situated farther in rear (from the company commander upward ) . B. Communication from the Aeroplane to the Ground. The infantry aeroplane is distinguished by long black, white, and red pennants at the outer extremities of the lower plane and flies at a lower altitude than other aircraft. The infantry aero- plane possesses the following means of communication with the ground : (4») Light-pistol cartridges. — To enable itself to be identified by the divisions to which it is allotted as their infantry aero- plane, and as a request to them to display their cloths, the aero- plane will discharge colored light signals when near the front line (see Appendix). Atmospheric conditions and the position of the sun may render it difficult to recognize and distinguish between the different colors ; repeated signals, moreover, can not be made, as but few cartridges can be carried. (b) Machine- gun fire. — Failing any other means of attracting the attention of the troops, short bursts of machine-gun fire can be delivered ; in the same way several series of rounds from the machine gun have proved a useful method of giving the " under- stood " signal or the " call " signal of units. There is danger of such signals being misinterpreted and of the aeroplane running short of ammunition if engaged by an opponent. (c) Signal lamps. — Infantry aeroplanes are equipped with signal lamps to enable them to give the " understood " signal 148 and to repeat Morse messages sent from the ground. These lamps can also be used to transmit reports received from below to such command posts in rear as are unprovided with wireless stations and at which it is Inadvisable to drop The report. (d) Wireless apparatus. — Each division has a wireless receiv- ing station for the receipt of argent messages requiring instant action; the infantry aeroplane must report to this station, using certain wave lengths and the preconcerted "call" signal. Demands for barrage fire, in particular, must be transmitted by wireless. It is the duty of divisional headquarters to cause the necessary telephone lines to be constructed, to keep them dis- engaged while the infantry llighr is in progress, and to detail a skilled operator to work the telephone at the wireless station in order that these demands may be transmitted, without any delay, to the proper quarters. (e) Dropping reports. — As reports which are dropped by means of the " Rauchmeldepatrone " (smoke indicator) very rarely fall quite close to the command post concerned, it is advisable only to drop them in those places where there is a certainty that the enemy's fire will not prevent a search for the reports. In any case a report should be repeated by telephone as soon as the aeroplane has landed. 5. METHOD OF CABK1 l\.S O O 03 rj C g HT3 O ftPuS 03 P •a . § 90 H<[+ a a 03 +J DO d >, o 9 E H « 154 I a e o tf H b o :i 1 t £ 2 i I t i "3 «2 w to CO . .e-a o £2 fl o IE -oflitleei** i i h P « hi a « O C .fl Xi =1 3 o o 5 £ 1 a a a a §• S S hJ S w w *? i a s a s »« s g ^ c 3 a o c o c^2 o ° W W W h u B 155 Sc c3 ® .2f ^ £.2 fl 3 03 03 OP ->r> 03 ** 2 = ® 52 •r 3 *■« ®.2 — £ O'O^S Ofl aj ^ O O %2*& |X5£ ♦a it 03 in II I! as +J CO 5 c.2 £-5 ° ^S'S'olS 33 2 i' h3 CO t I I B 08 s £2 « s -^1 £ •ss C 03 *"" CO ■•- ■— ' CP O «2« oo © ^ "■> ,=. -t-» US S3 C "Ct t^ CO £ 5 ^ c 03 60 a> - 2 2§ •*§> 2& 5a 5-2 6* fa •5 +» a ^3 o3 © gS g 22 o s» a IS -9 G..R o3 tfPlilfs 2. I\*s are always available for your use, and R. A. officers will gen- erally be able to observe for .you. A telephone from you to your guns is not always essential ; some simple system of visual signaling — such as on a rifle range — can be arranged. In such cases it is often helpful to arrange to signal " North, south, east, or west." Do not complain that you are short of tele- phone wire and then leave on the ground hundreds of yards of wire obviously out of use. Information. You must know all about the hostile trenches opposite you. There is an abundance of information available to you in divi- sional and corps "summaries," and you can check this and other information obtained by studying the aeroplane photo- graphs to be found at battalion and brigade headquarters. There are innumerable targets to damage and destroy, and you should always display keenness to engage them and to take part in any enterprises being carried out by the infantry or artillery. Gfn Positions and Cover. Are your gun positions good? Is there proper cover for the gun, ammunition, and detachment? Are the dugouts really strong, and have they got tiro entrances? Have you speaking tubes down to your dugouts? Are your magazines dry? Gas Precautions. Do you and your men thoroughly understand the order re- garding "gas precautions"? Have you gol your proper num- ber of gas masks, box respirators, etc? Bate you got Ver- morel sprayers and solution properly stored lor them? Are the gas blankets in position at entrances of your dugouts? Do you Carry out " gas drill," and do you thoroughly comply with the orders for "Gas alert " period? 159 Work. Do your men do a full day's work? If the men are allowed to be lazy, they will only complain when given work to do. Men who are worked hard and regularly, are properly looked after, and who do not see their time and work wasted by want of forethought on the part of their officers are always con- tented. Men who are contented and who have the knowledge that they are superior to the enemy are always happy. Turnout and Cleanliness. Are your men smart and properly turned out, especially when in billets? Are your emplacement, dugouts, guns, and stores all kept thoroughly clean? If your battery is not clean and smart Externally, it is a sure sign that it is lazy and dirty internally. Concealment and Action of the Enemy. Do you appreciate how easily German trench-mortar em- placements can be seen on aeroplane photos? Do you take pre- cautions that yours are better concealed? Do you construct dummy emplacements to draw fire off you onto unimportant spots? Do you take notice of what our own troops do on being shelled by trench mortars, and do you profit by assuming that the enemy probably does likewise when you shell him? Noncommissioned Officers. Your noncommissioned officers should be fully capable of car- rying on if you become a casualty ; can they, and do they under- stand your plans and methods? Rest. When you are in rest, do you visit your D. A., H. Q., D. T. M. O., and other trench-mortar offices in rest to exchange ideas? Do you provide your men with baths, amusements, change of diet? Do you inspect their clothing and equipment? Do you drill and instruct your men so as to keep them well disciplined and thoroughly up to their work? m Liaison. Have you got a close liaison with the Infantry and artillery, and do you visit company commanders frequently, and also any R. A. observers in your vicinity? Finally. Have you got that knowledge of your work winch brings <-<>n- fidence to you? ('an you answer favorably all the above ques- tions? If not, you must strive till you can. Is your battery better than the batteries on either side of it? If not, why nut J PRELIMINARY NOTES ON THE RECENT OPERATIONS ON THE FRONT OF THE SECOND ARMY. 1. Raids. The value of raids for purposes of training, identification, and morale was again proved, more particularly when carried out by the troops over the ground they themselves were to attack. 2. Liaison. (a) artillery and infantry. The principle which was observed of having senior artillery officers for liaison proved good and gave the infantry confidence. In bombardment each division had either a group or a double group of siege artillery working with it. The work was coordi- nated by the corps, but the divisional commander had always a direct call upon the group or double group and had a lieuten- ant colonel, R. G. A., as liaison officer. Whenever artillery liaison officers are attached to formations they should join some days before the operations begin, so that plans may receive the fullest discussion and coordination ; these officers are then able to deal with artillery questions as they arise. (B) OTHER UNITS. It is of great importance that information as to which units and formations have been selected for any particular operations should be given out early, so as to enable the brigade and bat- talion staffs concerned to get into touch with one another and arrangements to be made for liaison between the flanking units of both divisions and brigades. Arrangements should be made to obtain the distinguishing marks, code names, and signal calls of the division, brigade, and battalion on the flanks. j )7 84°-17 11 (161) 162 Wherever possible, meetings should also be arranged before the attack between parties of the officers, noncommissioned officers, and men of flanking battalions of neighboring divisions. 3. Rehearsals of Barrages. The value of rehearsals was very great. Gaps in the barrage, errors in timing, and also individual guns shooting short were detected and put right. Air photographs helped materially In this and were a great check upon ground observation, especially as to where gaps really were at different stages and what gun was systematically firing short. In corps and divisional prac- tice barrages an overlap was always made to avoid disclosing boundaries and also to practice junctions. Army practice barrages on the whole front undoubtedly drew the German artillery fire, but machine-gun fire should be in- cluded to make them realistic. Care should be taken, however, that the flanks of attack are not clearly indicated by practice barrages. 4. Camotflage. Articles of camouflage were found to be very Inflammable. The strictest precautions against fire should be taken by all battery commanders. 5. Gas and Oil Projectors. Considerable use was made of projectors both for gas and oil with, it is thought, satisfactory results. The tactics pursued were to shepherd parties of the enemy into woods and leave certain routes free from heavy shelling and then to concentrate with projectors on such places. 6. Machine-Gun Barr.\( i 9. (a) Madkine-gun barrages proved of nmcli valne. They re- quire careful Coordination with both artillery and infantry and should be practiced beforehand with artillery b a rr ag e s. The Infantry should also know that machine-gun barrages will be employed, so that there is no chance of their being under the Impression thai hostile machine guns are tiring. The machine- gun scheme should be on the simplest lines possible (b) The range at which the barrage guns fired varied from 2,250 to 2,750 yards, and although at first there was a certain 163 amount of nervousness as to the accuracy of the fire, all ranks finally testify to the value of the machine-gun barrage and the confidence with which it inspired them. As the attack progressed the " barrage " guns were moved forward in bounds. Each bound was about 800 yards, and it was found that the move could be accomplished and the guns set up in their new position ready to fire in one hour. (c) Belt filling was done in some companies by hand, but in the majority belt-filling machines were taken forward and set up under cover in shell holes. (d) It is considered essential for each gun in the barrage to have two new barrels for the first 24 hours. The normal life of a barrel is 25,000 rounds, but for overhead fire the barrel is inaccurate after 15,000 rounds. (e) It was found that where machine guns were sent forward with the assaulting waves they almost invariably got knocked out or suffered such losses of personnel as to be practically use- less on arrival at the objective. The best solution with regard to forward guns would seem to be for the sections to follow closely behind the battalion to which they are attached and attain their objective by a series of bounds, previously reconnoitered in each case by the section commander. (/) Prisoners' statements confirm the value of continual har- assing fire by day and night during the period immediately before operations take place. 7. Rest. Owing to the' slight chance of the troops obtaining any rest on Y/Z night, since they are either on the move or among bat- teries in the forward assembly area, it was found advantageous for battalions to arrange to have hours of silence in their camps on Y day. If the best value is to be obtained from the troops, it is essen- tial that their march to the forward assembly area on Y day or Y/Z night should be only a very short one. 8. Advance of Infantry Under Bakrauk. In a few cases in advancing over ground very broken, either in configuration, by mine craters, or by heavy shelling, waves were found rather difficult to handle and had some little difh- 164 culty in keeping up with the barrage, and it was found prefer- able to jump off in small columns and to deploy subsequently under the barrage. 9. Patrols and Consolidation. (a) Patrols from divisions with distant objectives were sent forward with the divisions to which nearer objectives were allotted in order to ascertain and report the latest develop- ments of the battle before the launching of the attack of their own divisions. Good results were obtained from these, but it is considered that full value can not be expected unless the patrols are lightly equipped. (&) It is a principle which must never be ignored that patrols are pushed out after the gaining of the final objective. Even if it is impossible for them to pass through the stationary " pro- tective " barrage at once, they should always be able to do so as soon as this has slackened down to fire on selected points. In addition to infantry patrols, use was made of special patrols consisting of one officer and four other ranks from the corps cavalry squadrons attached to divisions. These followed the method outlined in O.B./1782/A, dated May 26, 1917, and were despatched with the task of answering certain definite questions; in spite of the disadvantage of working to a limited objective, these were of distinct value and the information obtained by this means was most accurate. (c) Consolidation of the main ridge was intrusted to the troops who had captured it, and all arrangements wore made accordingly. The later advance to the Oosttaverne line was made by fresh troops of other divisions. 10. SOS Barrage. The aeroplane wireless SOS for barrage is a very valuable addition to other methods of calling for SOS. Protective or S O S barrage after gaining the final objective should be in great depth. In this case a very heavy and deep barrage of 60-pounders and heavy howitzers beyond the 18- pounder barrage was provided, and the counter attack from the Warneton line was absolutely crushed. 165 . 11. Transport of Water and Supplies. Much use was made of pack animals in the advance, and the carrying of water and tools to the troops in front line was effected by this means without difficulty. In some formations they were used for the issue of rations to units for some days previous to zero. Such rehearsal is most desirable in order to find out animals not handy with pack, or likely to gall, and faulty harness causing galls. Yukon packs proved most useful for the carrying up of stores, etc. As regards water, it was found that three petrol tins could be carried on one pack, but that training is required in moving in the bent position necessary. The carrying by each man of two water bottles (one con- taining water and one containing cold tea) was found to be a very satisfactory arrangement. 12. Salvage. All parties should carry back salvage when returning from the front area. It should also be regarded as a point of honor that no individual returns empty handed ; it is seldom realized how important a total of salvage can be effected by individuals in this way. 13. Sign Boards. Sign boards having the British name of the trench, etc., printed clearly in block letters and on both sides, and direc- tion boards, giving the way to dressing stations, brigade and battalion headquarters, salvage dumps, prepared previous to the operation, were most usefuL (S. S. 135, Sec. IX, par. 4 (vi).) 14. Congestion in the Forward Area. Salvage, burying, carrying, and other working parties should be withdrawn to their camps well behind the forward area when not actually at work. The congestion in the forward area caused by such parties is responsible for a large increase in casualties, additional shelling owing to amount of movement, and necessitates extra ration parties or transport and crowding in dugouts of men not employed in defense of the line. tea 15. Control of Traffic. (a) It was frequently found that officers and other ranks did not pay sufficient regard to the authority of noncommis- sioned officers in charge of traffic-control posts at important cross junctions. Considerable congestion is likely to result from this lack of discipline, and it rests with A. P. M.'s to in- sure by personal supervision that their orders are carried into effect. (b) The construction of switches around villages and other places or points which are known or likely to be constantly shelled by the enemy is a matter to which close attention should be given. 16. Tank Lessons. The general principles of the employment of tanks as an adjunct to the infantry attack require to be carefully studied by all commanders. These, as laid down in S. S. 164, were sub- stantially borne out in the recent operations; no new lessons were learned, but fresh emphasis, was laid on the following points : (a) There is still a tendency for groups of infantry to bunch behind tanks and follow them about. This not only results in an increase of casualties, as tanks invariably draw lire, but also in loss of direction and cohesion. (h) There is also a tendency to endeavor to retain tanks to meet possible eventualities; it can not be too strongly im- pressed upon all infantry commanders that when once the infantry are firmly established on their objective, the tanks should be withdrawn. Further, though tanks can render great assistance to infantry consolidating, their employment on this duty, as long as the enemy's artillery is active, is attended with grave risk and should be reduced to the minimum. The stationary employment of a tank can only be justified in the most exceptional circum- stances. (S. S. 164, par. 3 (iii).) On the other hand, several instances occurred where a derelict tank was successfully used to form a strong point In such cases the Infantry should take over the tank from its crow. (c) Pigeons from tanks Worked well and could have been put to more extensive practical use had other means of communica- tion' failed. 167 17. The New Organization. (a) The new organization worked very well and completely proved its value. There is nothing to add to S. S. 144, " The normal formation for the attack." In all training previous to 6perations the cadres of platoons and sections must be trained as such and kept ready to receive reen f orcements. Amalgamation should be resorted to when it is obvious that the unit will not be brought up to strength before the operations. (b) It was found that carrying parties sent up after the cap- ture of the objective could find their way through the hostile barrage with fewer casualties than those following closely in rear of the assaulting waves. (c) Heavy tools were in nearly all cases carried up by special parties and not on the men of the assaulting waves. (d) There is still a tendency for infantry to rely on artillery fire to deal with counter attacks rather than on the use of their own fire. OBSERVATION STATIONS. 1. To derive full benefit from the accuracy and rapid fire of modern equipment and to insure effective support to the other arms, correct observation with reference to the objective is of vital importance. The necessity for accurate fire on all occasions can not be overestimated, and is especially important in trench warfare, where the opposing trenches are often in close proximity to one another. 2. Although it is possible to determine by calculation the line and range required to be given to a gun to hit a target, and although these corrections may have been accurately worked out and applied, yet it is improbable that the maximum effect will be obtained on the target unless the actual fall of the rounds can be observed. To enable a battery to engage a target effectively, either reli- ance must be placed on observation from the air or a position must be selected from which the target can be clearly seen and the fire of the battery accurately observed and controlled. This position is called the " Observation station," and is commonly alluded to as the " O. P." 3. The closer this position is to the target, and the better the view of the ground in its vicinity, the easier it is to determine with accuracy the distance a shell has burst over or short of the target. To attain this accuracy of observation, it will usually be nec- essary to select an observation station within 600 yards of the target. Should it be necessary for any reason to select an observation station which is more distant than this from the target, it must be realized that the same accuracy of observation can not be obtained, even when aided by the best glasses and telescope. 4. In trench warfare it is the target to be dealt with that is the controlling factor in the selection of this position. In every situation there is probably one locality above all others from which the best view of a particular target can be obtained. (169) 170 The finding of this locality will often necessitate a prolonged and careful reconnaissance, and officers must not be satisfied until they have assured themselves that all ground, buildings, etc., have been thoroughly reconnoitered with this object In view. With the accurate maps now supplied it should be possible, more or less, to foresee what points are likely to give a good view of a particular locality, and much time can be saved by studying the contours of the map before going out to look for an observation station. The extent of country included in the reconnaissance should not be restricted to the immediate front allotted to a battery but should cover an extensive area, as it is impossible to be sure of obtaining the best possible view of the whole front or of a particular target (such as a machine-gun emplacement) unless the reconnaissance is carried out thoroughly. This is particu- larly the case in undulating country. In a moving battle, when time is the controlling factor, it will generally be found impossible to carry out such an extended reconnaissance, and, therefore, a position that fulfills the Imme- diate requirements may have to be selected. 5. It is impossible to lay down definitely the distance an ob- servation station belonging to a battery should be in rear of the infantry it is supporting. This distance depends mainly on the shape of the ground. When the ground is concave in shape, the observation station may be some distance in rear, but the necessity Cor accurate observation must not be overlooked. If the ground is convex the observation station may have to be sited in the front-line trench or immediately behind it. • When this is the case it is generally due to the selection of the infantry line having been made without taking Into considera- tion the requirements of good observation for the artillery. As the position of the observer in the latter case renders him liable to be put out of action by any hostile bombardment of his portion of the front line or to interference caused by the retirement of our infantry, or to capture in the event of a successful attack by the enemy, or at least to have bis conn munications cut, it is imperative in such a situation to provide a second or reserve observation station farther to the roar from which the ground behind the front line is visible, and this station should be maintained ready for occupation in case such an emergency should arise. 171 If a position can not be found from which the whole of the front is visible, and as accurate fire is essential, the observa- tion must be from a point which gives a clear view of at least one datum point, so that the error of the day may be corrected. In open warfare it may be necessary to select a position still farther to the rear so as to obtain a more extensive view of the ground over which the fire of any particular battery may be required, and also because it may be impossible to keep up communications with an advanced observation station. 6. Officers must be able to range their batteries at short notice on objectives far to a flank, and must know where the best view of such localities may be obtained. 7. In selecting the position for an observation station the following requirements must be kept in view : (a) It must be suitably sited to carry out the task in hand. (b) It requires to be carefully screened, so as not to be recog- nized by the enemy. (c) It should, if possible, have a concealed means of approach. (d) It should afford cover and protection to the observing officer and his assistants. (e) It should allow of intercommunication with the infantry. 8. Observation stations may be classified as follows: (a) Permanent, (ft) Extemporized, (c) Temporary. (a) A permanent observation station must be strongly con- structed and be sufficiently large to accommodate several ob- servers and their assistants. A covered approach is a matter of vital importance. It must be provided with a dugout capable of resisting at least a 5.9-inch howitzer shell. It should afford an extended view of the front. It should not be exposed to fire directed on the infantry front- line system of defenses. The dust and smoke and the moral effect on the observer, if posted in the infantry line, render observation from it difficult if not impossible. (&) An extemporized observation station is used to carry out a special task, such as the destruction of a machine-gun em- placement or wire cutting. It should be provided with splinter-proof accommodation for the observer and his assistants. The field of view is of sec- ondary importance. 172 (c) A temporary observation station is used in open warfare when there is insufficient time available to provide artificial cover. In this case use is made of houses, trees, haystacks, trenches, and shell holes, etc. 9. Every battery must be provided with at least one observa- tion station, for the maintenance and control of which it is re- sponsible. This station must afford a good view of at least one or more datum points. All observation stations should be made as strong as possible, but the fact that a battery is provided with a strongly con- structed post must not deter officers from utilizing the best places available, irrespective of cover, for the observation of any par- ticular task they may be required to carry out. 10. An observer in one observation station may have little chance of seeing more than a limited extent of the ground which his guns can cover. Moreover, it is often not realized that the principle of con- centration of fire can not be put into practice unless batteries are prepared to fire on the whole extent of their arc, however far it may be outside their normal defensive zone. Arrangements must therefore be made to have a number of observation stations along the front, so that every possible part of the hostile lines is visible from at least one post. A concen- tration of observation stations at any one point must be avoided as far as is possible. As it is practically impossible to provide each battery with a sufficient number of stations from which to observe the whole of the ground covered by the arcs of fire of its guns, arrangements must be made to form group O. P. exchanges, and these exchanges must be connected up to the exchanges of neighboring groups. Such exchanges must be made practically impervious to artil- lery fire. By this means it is possible to provide a telephone system that will enable each battery to be ranged on any particular point required, and an observer can direct the tire of any battery within range on to any target in his zone of observation. This arrangement simplifies the concentration of fire on any point, but, in order to derive full advantage from it and thus inflict the greatest damage possible an the enemy, iris impera- tive that every ollicer of the artillery should he capable o\' send- ing hack observations for any battery. Irrespective of its Qatar*. 173 11. There are several purposes for which an observation sta- tion is required, which differ somewhat with the nature of the battery, the task to be undertaken, and the tactical situation. They may be classified as follows : (a) Field guns. The 18-pounder quick-fire battery is usually charged with the direct support of an infantry battalion holding a front. This front is watched by day and often at night by an artillery ob- server in order that any movement of the enemy by day may be at once seen and dealt with, and signals for support from the infantry responded to at night. An observation station for this purpose should command, if possible, the whole zone allotted to the battery without being too far back, but it should not be in the front line if it can be avoided. (See par. 5.) It should afford a view of the ground over which the enemy must attack for at least 200 yards in front of our own front line, and it should be possible to overlook a portion of the ground behind this belt over which the enemy may be expected to move his troops. If it is near the battalion or company headquarters, the com- munication with the infantry is facilitated. (b) Field howitzers. The 4.5 inch howitzer battery is usually responsible for the whole front covered by the field artillery brigade to which it belongs, and, further, it is required to :':pport the brigades on the flanks. It is seldom possible to obtain an observation sta- tion with this field of view. Observation from several stations is therefore necessary. The usual custom is for the battery to have a permanent station in some central position and to supple- ment the observation by utilizing observers in the other observa- tion stations belonging to the brigade and division. This is rendered possible by the provision of O. P. exchanges. (c) Heavy howitzers. The siege battery may be required to fire on any portion of the enemy's lines which the arcs of fire of its guns can cover. It follows therefore that officers of the siege artillery require an even more extended knowledge of our own and the enemy's 174 trout from the point of view of observation than officers of the field artillery. Furthermore, the heavier the nature of the artillery the more important it becomes to obtain close and accurate observation of a target. The provision of suitable O. P. exchanges for the siege artil- lery is even more important than for the field artillery. The O. P. exchanges of both field and siege artillery should be connected, so that full advantage may be derived from all O. P.'s. (See par. 10.) (d) Heavy guns. The chief role of the heavy batteries is the neutralization of hostile guns, and the searching of distant approaches, observa- tion on which is Impossible except from the air. When an aeroplane is not available, this shooting must usu- ally be done from the map, the guns being calibrated from time to time on a datum point. As heavy batteries are also employed to enfilade trenches, they must be provided with observation stations giving a good view- not only of the datum points but also of as much ground in the enemy's front system as possible. These stations must be con- nected up to the observing post exchanges, as in the case of the siege artillery. 12. In addition, heavy and siege batteries are often required to find observers by day and night to assist the field-survey i>o-ts in the spotting of flashes of hostile guns. Such observing sta- tions are often far bad'- and on the highest ground available. 13. An observation station should contain: (1) A panorama sketch of the view from it. (2) Orders as to the procedure in ease of S. o. s. (3) Orders as to the procedure in case of a mis attack, par- ticularly Instructions as to the use of the telephone, (4) A diary of what is daily observed on the front, and in- formation which may he of Importance to a battery Which may have to take over the zone. This should include the known and inspected positions of trench mortars and machine guns, and localities where the enemy's movements are visible. When the observation station is behind the reserve line of trenches, an artillery board may be added. • 175 14. The supreme importance of quickly establishing forward observation stations in the event of a successful advance can not be too strongly impressed upon all artillery officers. It is in such a situation that the greatest advantage may be reaped from the early occupation of advanced observation sta- tions and commanding heights beyond the original hostile front line, which afford direct observation of the terrain occupied by the hostile artillery. This is especially important in the case of those batteries al- lotted to the counter-battery groups. NOTES ON COMMUNICATIONS DURING RE- CENT OPERATIONS ON THE FRONT OF THE SECOND ARMY (PROVISIONAL). (Issued by the General Staff.) 1. Preparatory. (a) A considerable number of poled cable routes on perma- nent poles were used between the open wires and buried cable system and proved their usefulness. Telephones were withdrawn from in front of brigade head- quarters and Fullerphones utilized as far as possible. (&) The R. F. C. were given their own routes and exchanges throughout ; they controlled their own traffic and were able to make the best use of these lines to the mutual advantage of all concerned. (c) An army report center was established with direct lines to- All field survey O. P.'s. Special army O. P.'s. Forward kite balloon and K. B. sections. Army headquarters. Liaison officers at each corps and division. Corps heavy artillery headquarters. R. F. C. and antiaircraft systems. Much information was received on the direct line from the forward balloon. (d) Buried cables: The gridiron system was adopted where possible, with a cable head in the front line to each attacking brigade sector averaging 20 pairs. Forty pairs are recom- mended. One corps buried a complete new system for the artillery, taking the old artillery lines into the command system. The corps allotted all lines, and the results proved this to be the preferable arrangement. 9784°— 17 12 (177) 178 The other corps added to their old system and the allotment of lines was done by the divisions. A pilot line to all test and junction points is a necessity, and a man who knows the system should remain at each such point to make the connections as ordered by the signal officer i/c of the bury. (c) Both in the case of the infantry and of the artillery the schemes of communication should be drawn up and orders is- sued by the staff, sufficient time being given to the signal service to enable them to be carried out. Where this principle was adopted the results were good. 2. Dtjbing the Battle. (a) The approved principles of forward intercommunication in battle worked well. They should not be rigidly applied to all situations, but allow of sufficient elasticity to meet the vary ing conditions. ( b ) Cable took the majority of the work back from brigade forward stations. The enemy artillery fire was, generally speak- ing, weak, and in consequence it was in most cases possible t<» keep lines through continuously when once established. The lighter types of cable were found most useful (D. II and D. VII twisted) for the first lines. They are lighter and more portable and are as likely to stand as the heavier types. (c) The power buzzer produced some excellent results, ami too much stress can not be laid on the neeessity of training personnel with this apparatus. Amplifiers should not be placed in cable beads or signal offices, Where this was done they were jammed. {d) Visual: The Lucas lamp was used extensively ami proved invaluable. Shutters and flags were used by battalions and companies. Tlioy arc n«>t of much use to brigade forward stations. (c) Pigeons were not much used, but messages sent olT iron orally arrived in good time. The supplies were good. (/) Oreen flares were easily seen until the sun rose. During daylight they should be lit in groups, as singly they are most difficult to pick up. Brigade and battalion headquarter- are of value, and if OlpSSfd %\ imn called for by the contact patrol affect u great saying of time, 179 3. After the Battle. (a) Communications after the battle were maintained by the system established daring the flight, improved and enlarged until such time as the buried cable system could be pushed forward. The artillery extended their O. P. lines for necessary regis- tration purposes. In one corps a special battalion was detailed and trained to bury cable from " cable head " immediately the objectives wore secured. This proved very successful and is recommended. The buried cable system to be adopted should be laid down by the army and should be continuous without thought of boun- daries. (6) In one case difficulty was experienced where one division passed through another. It is desirable for both to have their own lines to cable head before the commencement of the battle. The allotment of lines should be made by A. D. signals of corps, and not by divisions. (c) Where possible it is advisable temporarily to enlarge the area parties. This should be done an appreciable time before operations commence, to enable men to learn thoroughly the system in their area. (d) The advantages of the R. F. C. being provided with their own system of communications were pronounced. The army intelligence report center for the quick dissemination of informa- tion by direct lines was of great value. (e) It is desirable to have an officer at cable head to prevent confusion in picking up lines or overcrowding in the cable head dugout. (/) A reserve of light cable as well as the armored squad for the bury when dug must be kept near cable head. (g) The "A" detachment of brigade forward stations went over if anything too early and frequently became involved in the " mopping up." Loss of men and gear resulted. (h) The necessity of placing some distinguishing mark at the entrance to a dugout when brigade forward station has been established. On one occasion our " mopping-up " parties bombed a brigade forward station. (i) Four-line exchanges were made with electric-light sockets, and plugs proved useful at relay posts, for listening-in on all lines. 180 (;) Difficulty was experienced with code and position calls during the battle. Position calls for exchanges and test points work well, but when used for units then; is apt to be confusion . Code calls should be used by units after zero whether they are in our trench system or no. Three or more units may use the same headquarters on the same day. (k) Headquarters or formations should move up into their battle headquarters in sufficient time to allow signals to make the necessary corrections, etc., to enable the men to learn the new system before zero day. Where this was not done con- siderable loss of efficiency was evident. (0 "The urgent operation priority" prefix defeated its own object. All officers sending information consider their messages " urgent operation priority." (m) The special officer named in S. S. 148 ("Forward inter- communication in battle"), Section II, paragraph 3) (&), as the officer at the brigade forward office in control of the method of transmission must realize that it is his duty to take the responsi- bility for marking really important messages, " Priority." (n) With a limited objective it is necessary to push the cable head forward immediately. The artillery may require those wires for registering their batteries on new lines. (o) Sufficient stress is not yet laid on the necessity for des- patching an important message in duplicate to increase the chance of its safe arrival. Where possible such messages should be sent by alternative methods; when runners only are employed they should be despatched with the duplicated mes- sage at a 100-yards interval. (p) Closer touch is desirable between battalions and the relay system of runner posts organized by brigades. The relay parti should be marked so as to be easily recognizable from a distance : e. g., with a large colored flag by day and with a colored lamp by night. In one instance it was found useful also to mark with small colored flags the shortest route for runners from brigade headquarters to the brigade forward station. Alterna- tive routes should not be marked. NOTES ON THE USE OF SMOKE. (Issued by the General Staff.) Use of Smoke Screens. Smoke screens may be employed with one or more of the following objects in view: (a) To protect the flanks of assaulting or advancing infantry by preventing observation from enemy observation posts, high ground, and salients, or from ground from which the advance is liable to be enfiladed. (&) By infantry in the attack, to blind hostile machine guns. (c) As a feint to induce the enemy to expend ammunition needlessly or to put down his barrage. (d) As a feint to draw the enemy's attention to a front on which no attack is being made, and thus hold his troops in their trenches and prevent them from going to the assistance of the front attacked. (e) In the case of a smoke cloud used offensively,, to simulate gas, with a view to lowering the enemy's morale and forcing him to use his gas mask. To make this effective gas should occasionally be mixed with smoke in order to drill the enemy into the belief that it is never safe to remain in a smoke cloud without wearing his gas mask. (/) In flat or open country to conceal concentrations of guns and troops, and possibly to screen roads, forming-up places, and lines of advance. To conceal the flashes of a battery which is in view from the enemy's observation posts, and to hamper observation from the air. Ground and troops can seldom be concealed from hostile aeroplanes or kite balloon observation behind smoke screens, and although they may be concealed in smoke clouds such clouds attract the enemy's fire and are therefore dangerous. A smoke cloud, however, may be used with success to inter- fere with any attempt of the enemy to range accurately with aeroplane observation on one of our batteries. (181) 182 As stated above, smoke tends to attract the enemy's fire. Smoke screens should normally be formed, therefore, at some distance (about 400 yards) from the object to be concealed. Troops attacking through a smoke screen are very liable to lose direction. This fact should be carefully considered before troops are committed to such an operation. When smoke is to be liberated on the flank of an assault, care should be taken, by defining permissible wind limits before- hand, that the cloud does not pass across the front of the assaulting troops. While the use of smoke may conceal the position and move- ment of our troops from enemy observation, it may also hide them from our contact patrol aeroplanes. This must be con- sidered when determining the nature and extent of smoke screens and careful precautions should be taken to preserve liaison be- tween the infantry and the flying corps. When the use of a smoke screen in operations is intended. the enemy should be educated to associate such a screen with some object other than the real one, e. g., he may, by means of a practice smoke screen, followed by no action, be led to suppose that the object of the demonstration is to compel him to expend ammunition uselessly. Smoke-Producing Substances Available and theik Nokmai. Uses. The following means of producing smoke are available: (a) P bombs and No. 27 (white phosphorus) grenades (b) Single smoke cases, type S. (c) 18-pounder and 4.5-inch howitzer smoke shells. (<1) 4-ineh Stokes mortar smoke bombs: 13-pounder shell, range 450 yards; 25-pounder shell, range 900 yards. In addition, experiments are being carried out with smoke generators of various descriptions, and means of producing smoke with burning straw tightly packed in sacks, damp hay. tar barrels, green wood. etc. can be improvised. P bombs are designed partly as incendiary and partly as smoke-producing articles. They are tilled with phosphorus, which is scarce and expensive. In consequence the supply is at present limited. The No. 27 (white phosphorus) grenade is being introduced to replace the P bomb. It can be used either as a hand grenade or as a rifle grenade with a range up to about 200 ynrdv \i 183 present 20 per cent of rods and cartridges are supplied, but on the introduction of the new cup discharger all No. 27 grenades will be capable of use as rifle grenades. P bombs and No. 27 grenades are primarily designed as infantry weapons for offen- sive operations, and are suitable for burning dugouts, blinding machine guns, or screening small local attacks. Owing to their scarcity it is very uneconomical to use them in forming large smoke screens. It should be noted that on exploding these bombs scatter burning phosphorus over a circle of about 15 to 20 yards radius. Single smoke cases, type S, are more easily obtained than P bombs or No. 27 grenades, and are less costly to manufacture. As smoke producers they are slightly less efficient than P bombs, and have practically no incendiary effect. They are portable and are designed for use by infantry in active opera- tions. They are suitable for producing smoke which is intended to simulate gas or to be mixed with gas. They are useful for blinding machine guns or for. screening local attacks, but are not so suitable for this purpose as P bombs or No. 27 grenades. They may be used for concealing concentrations of guns or troops, battery positions, or areas. The following table gives a rough idea of the comparative weight of phosphorus and approximate efficiency of the several smoke-producing articles : Article. Weight; Effi- ciency. No. 27 grenades P bombs 18-pounder 4.5-inch howitzer 4-inch Stokes (light) . . 4-inch Stokes (heavy) 14 ounces white phosphorus. 16 ounces red phosphorus 1(H ounces white phosphorus 4 pounds white phosphorus. 4£ pounds red phosphorus. . 1\ pounds white phosphorus. Eighteen-pounder and 4.5-inch howitzer smoke shells and 4- inch Stokes mortar smoke bombs are filled with phosphorus and have a considerable incendiary etfect. They are suitable for — (a) Blinding enemy observation points, both in attack and defense. (b) Forming a smoke screen to conceal an advance from observation from a iiank. (c) Blinding salients in the enemy's line from which enfilade fire is expected. 184 (d) Blinding commanding ground and suspected machine- gun positions. (e) Improving the screening effect in a barrage of shrapnel or H.E. (applies to gun and howitzer smoke shell only). The supply of both shells and bombs is, however, strictly limited. Which should be employed on any given occasion will depend primarily on the resources available and the range to the points at which it is desired to form a screen. As a general guide it may be taken that the following number of shells are required to form an adequate smoke screen under normal conditions : 18-pounder smoke shell : Two rounds per 10 yards per minute. 4.5-inch howitzer smoke shell : Two rounds per 15 yards per minute. Successful results have been obtained by firing groups of eight shells at 200 yards' interval per two minutes with a flank wind of moderate velocity. The incendiary effect of these shells is quite considerable. Showers of burning particles are scattered around within an area of about 10 yards' radius. The stronger the wind the farther must be the source of the screen from the object. Experiments have shown, however, that a screen can be formed even in a strong wind. The best wind for the use of gun and howitzer smoke shell appears to be one having a velocity of about 14 miles per hour (20 foot-sec- onds) and blowing across the object to be concealed. One hundred yards per 10 foot-seconds of wind may be taken as a general guide as to the distance from the object at which artillery smoke shell should be placed. The smoke will rise to a height of at least 200 feet. For the 4-inch Stokes a gentle wind of from 2 to 4 miles per hour is the best. In forming a screen with the 4-inch heavy bombs 10 per cent might be burst in the air and the remainder on the ground. The 4-inch Stokes smoke bomb has a maximum range of 450 yards with the light bomb and 900 yards with the heavy bomb. The mortar and ammunition are heavy and not very portable. Cases have occurred, however, in which, by making special arrangements for carrying parties, 4-inch Stokes mortars have been taken forward with the advancing troops and have suc- ceeded in coming into action and forming a Hank screen at a suitable moment during the advance. 185 Phosphorous smoke is the most persistent form of smoke avail- able. In a wind of 3 to 6 miles an hour the depth of a cloud established by 4-inch Stokes mortars approaches 2,000 yards; with winds of higher velocity gaps are apt to develop in the cloud at distances over 1,000 yards from the burst of the bombs. Considerations Affecting the Quantities of Smoke-producing Substances Required to Form a Screen. The amount of smoke-producing substances required to form the screen depends on many considerations, the most important of which are as follows (a) The extent of the screen: As a rough guide it may be assumed that the width of the screen should be from two to three times the width of the object to be concealed (as seen by observers from the points which are to be protected from the enemy's observation). (b) The duration of the screen. (c) The direction from which the enemy can observe the object or area to be concealed : The greater the number of points from which an object can be observed by the enemy the greater will be the amount of smoke-producing substances necessary to conceal it. As a general rule more smoke is required to conceal an advance from observation from a flank than from observation from directly in front only. id) The distance of the object from the enemy's observation pasts: The greater this distance the more effective the smoke cloud. (e) The direction of the wind: The difficulty of concealment increases if the direction of the wind is variable. In such a wind the smoke source should be mobile, as it may become neces- sary to change its location from time to time. Failing this, it may become necessary to stop the generation of smoke alto- gether. (/) The velocity of the wind : The density of the smoke cloud diminishes considerably in proportion as the velocity of the wind increases. In a wind of over 20 miles per hour it is prac- tically impossible to form an opaque screen. It should be noted that in hot weather the smoke tends to rise from the ground, and there is a greater tendency for gaps to form. 186 It should be remembered that the effect of phosphorous bomb* of all kinds is cumulative, as the globules of phosphor . tinue to burn on the ground for from 15 to 30 minutes. As the c'oud in the case of phosphorous projectiles is at its thickest soon after the burst, it will be maintained more evenly by adding small quantities at frequent intervals of time rather than by adding large quantities at greater intervals. To obtain the best results with the greatest economy in smoke-producing substances, it is necessary that the formation of the smoke screen should be very carefully organized. All personnel required for providing smoke screens should be trained beforehand in the use of the actual material which is to be employed. A simple rehearsal beforehand is most valuable. The program which is to be followed should state in detail the rate of expenditure of the smoke-producing substances and should be given in writing to the personnel of each moki source. No definite rules can be laid down as to the exact quantities of smoke-producing substances required to form a screen, as the conditions vary to a very large extent. The following examples are. given for guidance: Examples of Smokk S< kkens. (1) Object to be concealed: Concentration area on a front of 2,000 yards. Direction of the wind : Parallel to the enemy's tre nc h es. Velocity of the wind : Six to eight miles an hour. Material available: Single smoke cases, type S. A smoke screen should he formed 4.0(H) yards long and 40t> yards in front of the forward edge of the concentration area. Groups of two men each should be placed 150 yards apart on the line of the intended screen. Each group should tight six smoke cases every 2 minutes. Thus, if the screen is to be main- tained for a period of 2 hours, 10,800 smoke cases will be required, Personnel required, 60 men. The men should take advantage of any cover available, and each group, if possible, should be provided with a watch. (2) Object to be concealed : Ottneentrfttlon area on a front of 2.000 yards. . Direction of the wind: Toward the enemy. 187 Velocity of the wind : Six to eight miles per •hour. Material available : Single smoke cases, type S. A smoke, screen should be formed 4,500 yards long and 400 yards in front of the forward edge of the concentration area. Men should be posted singly and 25 yards apart along the line of the intended smoke screen. Each man should light one smoke case every 2 minutes. Thus, if the screen is to be main- tained for a period of 2 hours, 10,800 smoke cases will be required. Personnel required, 180 men. (3) Object to be concealed: Concentration area on a front of 2,000 yards, from a balloon at an altitude of 3,000 feet and 6,000 yards distant. • If the smoke screen is formed 400 yards in front of the for- ward edge of the concentration area, it would be necessary to have a smoke screen 200 feet high in order to conceal the for- ward edge of the concentration area from the balloon, and much more than that to conceal the rear edge. A certain amount of screening effect might be produced by bursting 4-inch Stokes bombs in the air, but this method can not be relied upon, and is uneconomical. As already stated, therefore, it will seldom be possible to use smoke successfully to screen areas or objects from hostile kite balloons, unless there happens to be a considerable rise in the ground between the balloon and the object to be concealed and on the top of which the smoke screen can be formed. P Red Phosphokus Bombs. Front to be screened, 150 yards. Ten men extended to 15 paces. Each has ready in a sandbag : 1 P bomb with detonator and Brock lighter. 8 P bombs without detonators. 1 strip sandbag soaked in paraffin. 1 piece corrugated iron 2 feet by 1 foot. 1 knife with tin opener. 1 box matches. On whistle signal the detonated P bombs are thrown 15 yards down wind and burst. Each man then opens a P bomb with tin opener and spreads red phosphorus over square foot of cor- rugated iron, leaving one end free for carrying if wind changes. The phosphorus is lighted as soon as possible by means of the strip of sandbag soaked in paraffin. The contents of a fresh P m bomb are added to each burning pile every 15 minutes. Fresh phosphorus must not be added by every man at the same time or the cloud will diminish. Duration, 2 hours, 90 P bombs. Note.— P bombs must not be opened previous to operations, as the phosphorus is liable to catch fire spontaneously. 4.5-Inch Smoke Barrage. A method adopted on one "Occasion was as follows : The four guns of the battery were concentrated on a point 400 yards to windward of the place where the commencement of the barrage was required. The ^ind at the time was 40 foot-seconds ; the relation of the distance, 400 yards, to the wind, 40 foot-seconds, may be worth noting. The guns were fired at battery fire (10 seconds) and the re- sult was effective. NOTES ON SCREENS (PROVISIONAL), (Issued by the General Staff.) Employment. Screens are extensively employed for the purpose of conceal- ing from direct observation — (a) Roads, tracks, trenches, or areas. (&) Ground which is waterlogged, where it is impossible to dig communication trenches, and over which it is necessary to move troops. (c) Battery positions or gun flashes. (d) Work in progress. (e) Dumps. Also for the purpose of — 1. Thickening hedges which are not sufficiently opaque of themselves. 2. Encouraging the enemy to waste ammunition. Their main function is concealment, so that the enemy can only fire on the chance of there being a target behind them, instead of at an observed and definite object. Typks. To be effective, screens should fulfill the following conditions : They must be opaque enough to achieve the purpose for which they are erected and at the same time not susceptible to ex- tensive damage by weather or shell fire. If damaged, they must be easy to repair. The forms of screening generally found of most value are : 1. Wire netting garnished with grass, brushwood, or canvas strips. 2. Brushwood interwoven in horizontal wires stretched be- tween rigid uprights. Shell fire has practically no effect on such screens unless a direct hit is obtained, and even then, if properly constructed, the effect is very local. They also stand the weather well. Grass screens when dry are, however, somewhat inflammable. (189) 190 Other Forms. (A) In certain cases solid canvas screens are necessary — e. g., to hide flashes or movement at close range (up to 2,000 yards). They are highly susceptible to damage by weather or shell fire, must be extra firmly supported, and, if possible, backed with wire netting. (B) Coir screening (which is a generic term for coconut or jute matting) in single thicknesses is transparent Used double it forms an excellent and quickly constructed screen. It is useful as a temporary expedient, but does not weather well. It should always be reinforced with longitudinal wires. Opacity. It must be recognized that perfect opacity under all conditions of light and background can only be obtained by the use of perfectly opaque material, such as corrugated iron. Canvas itself is not always opaque — e. g„ when the sun is low behind it. One must therefore be satisfied with a compromise — a screen that is comparatively opaque under normal conditions; that is to say, one which hides movement from anything but close and continuous scrutiny. The screening effect is much influenced by the background and the angle of view. A comparatively transparent screen may be successful if the background is of a color generally similar to the objects to be screened, is broken by trees and hedges, or is viewed from an angle other than at right angles to its surface. Unless assisted by natural accidents of environment it is necessary that three-quarters of the surface of the screen should be made of opaque material if it is to hide movement at medium range (2,000 to 4,000 yards). Yisihiijty. There are two distinct categories of screens: 1. Those which are obvious to the enemy as screens. 2. Camouflaged screens, designed to conceal and yet escape detection themselves. These latter are either made of — (a) Solid painted canvas or wire netting garnished with strips of canvas, grass, etc., colored in patches to present a general landscape effect or to represent hedges. 191 (6) Solid canvas carefully painted to reproduce a definite locality — brick wall, ruins, and such like. Camouflaged screens can rarely serve their purpose for any length of time, and are only in exceptional cases (where they are only required for a few weeks) worth the time and trouble expended on their manufacture. Their defects are : 1. That the effect obtained by painting will only last a short time when exposed to weather, and will not vary with the natural seasonal changes in surroundings. 2. That they require greater care in construction and more maintenance, are highly susceptible to damage by weather and shell fire, and are inflammable. 3. That it is very doubtful whether they deceive the enemy; should they not do so they are only performing the function of an ordinary screen, i. e., that of concealment, but have taken longer to construct. It is to be remembered that they are exposed to steady direct view as opposed to the comparatively fleeting examination from an aeroplane to which camouflage gun covers are exposed. The following are examples of the successful use of camou- flaged screens: 1. Work on exposed battery positions about 1,800 yards from the enemy's front line was made possible by the erection of screens composed of raffia on wire netting. These screens were mounted on wooden trestles, of a maximum height of 10 feet. These enabled the raffia netting to be put up at a slope and so to simulate a bank or false crest. The extremities of the screen were sloped gradually to the ground by using progressively lower trestles. Both front and back slopes were furnished with raffia netting, in order to give sufficient thickness to conceal flashes. The top of the screen was made irregular to avoid a hard outline, and the slopes were gentle. 2. In another instance imitation brick walls painted on canvas backed with wire netting were erected for a similar purpose. 3. Imitation hedges were made of a combination of raffia, canvas strips, and brushwood on wire netting to conceal a bat- tery position which otherwise would have been in direct view. In this case an existing hedge that was in rear of the position, from behind which the guns were unable to fire, was removed, and the imitation substituted in front of the guns. 192 It Is a general experience that newly erected screens are shelled by the enemy for a short period after erection, but that he soon gives this up if damage is repaired immediately. A good example of this can be given in a case where over 7,000 yards of screening, consisting of hay bands interwoven in wire netting were erected five months ago. No attempt was made to render the screen inconspicuous. It was shelled to some extent, but any damage caused was immediately repaired. The screen is still fulfilling its purpose, i. e., that of concealing what goes on behind it. There is no doubt that if screening is carried out on a com- prehensive scale, and with a continuous policy, localities which would normally be under observation and subject to deliberate shelling become practically immune, and this does not depend upon the invisibility of the screening erected but on the dis- tribution. Siting. Roads running at right angles to the front line are best concealed by hanging vertical screens between trees, houses, or poles across the road. For roads running parallel with the front line it is advisable, when possible, to site the screens at least 50 yards from the road in order that shell fire directed at the screens should not cause damage on the road and vice versa. Additional ad- vantage may be gained by varying the distance, and using lengths of screen en Echelon. Such screens may have to be made specially high, but at the same time the lower edge can be correspondingly some dis- tance off the ground. Short lengths of about 30 yards placed en echelon, and over- lapping each, other, are preferable to long lengths. This method permits of passage way, and limits damage by shell fire, and the line of route screened not being denned, becomes difficult to range on. Screens have been used successfully to hide gun flashes from the front and from a flank at night. In one case where the flashes were visible from a flank, a long solid canvas screen (painted a dark color) was placed 50 to 100 yards on the right front of the battery. This was found difficult to maintain, and six small screens were substi- tuted, one about 4 yards to the right of the muzzle of each 193 gun, and running out about 8 yards to the front. They were about 8 feet high, of which only the top 6 feet was canvas. They were dismantled during the day and reerected each night in socketed holes. Manufacture, Erection, and Maintenance. Whenever possible, screens should be attached to existing objects such as trees, hedges, houses, etc. If poles have to be used instead, they should be sunk well into the ground and well guyed. The screen should be both suspended from longitudinal wires and fastened with staples to the poles. The following methods of bracing have been found satis- factory : 1. The uprights joined by longitudinal wires 3 feet apart and guyed to stout pickets set midway between each pair of uprights. Each upright is therefore secured to four pickets, two of which are shared by the upright on either side. 2. Cross diagonal bracing between each pair of uprights, which are guyed in the normal way. Guys should consist of at least four strands of No. 14 gauge wire or their* equivalent. Uprights should be of at least 3-inch timber. It is convenient when manufacturing screens in back areas to make them up in bays of 30 feet, with intermediate sup- ports 10 feet apart, 30 feet being a fifth part of an ordinary roll of wire netting and a convenient length to handle. In order to localize the effect of shell fire, it has been found advisable to hang each longitudinal width of wire netting in- dependently on a longitudinal wire between the uprights. It is important that the manufacture and assembly of screens should be well organized, so that the actual erection can be carried out rapidly. The adoption of a standard type of screen, which suits the locality and will serve anywhere, will result in economy of time and labor. Strips of canvas interlaced in wire netting will make such a screen. The strips should be 2£ inches wide, and threaded through every three or four meshes vertically, leaving no in- terval horizontally except for the twisted wire between ad- joining meshes. The opacity is considerably increased by the 9784°— 17 13 194 use of alternate vertical bands of plain and dark-colored can- vas, each band being about a foot wide. It is important that there should be a strong contrast between the plain and colored canvas. This screen is effective from ranges of a mile upward. Still better results can be obtained if the color is arrange* 1 on the vertical bands so as to produce a checkered effect. This can easily be done in the manufacture, for the screens are made up of wire netting (which is 3 feet wide), which arc subsequently joined to form screens 6 feet or 9 feet high. It is simple to arrange either in the manufacture or in the i bling, that the colored band on one 3-foot width is mated to a plain band on its neighbor above or below. It is recommended that maintenance parties should be de- tailed to effect immediate repairs, and that a reserve dump of material be formed near any extensive range of screens that are likely to be damaged. INSTRUCTIONS FOR THE DEMOLITION OF HOSTILE GUNS WITH 3-INCH STOKES TRENCH MORTAR BOMBS AND SPECIAL SLOW FUSE. (Issued by the General Staff.) 1. A slow fuse should be made up of a length of Bickford fuse with a fuse lighter fixed to one end and a No. 8 detonator crimped to the other end. The fuze should be cut to burn for 1£ minutes. It has been found convenient to pack the fuses in tins con- taining 10 fuzes and 4 spare fuze lighters. The contents should be labeled on each tin. Care must be taken when crimping the detonator onto the Bickford fuze to leave a space of one-fourth inch between the end of the Bickford fuse and the fulminate. 2. The bombs are the ordinary 3-inch Stokes bombs without their fuses or components. 3. To demolish a hostile gun : (a) Open the breech, place the bomb in the breech of the gun, with a cartridge container forward as far as it will go. (&) Insert the detonator end of the slow fuse into the gaine tube of the bomb and press it gently home. Secure the fuse so that the weight of the fuse lighter does not pull the detonator out of the bomb. (c) When the gun has thus been prepared, withdraw the safety pin from the fuse lighter and press the cap down, at the same time turning it around. As soon as the fuse is lit, take cover. Note. — (1) The normal rate of burning of Bickford fuse is 1 yard in 90 seconds, but this time may vary by as much as 15 seconds in either direction. (2) In taking cover the party should spread out and warn off any approaching troops. The fragments may carry 300 yards. (195) 196 (3) If the breech can not he opened — (a) In the case of a held gnu, place the homb between the gun and the seat (so that it touches the gun) on the muzzle side of the shield. (b) In the case of any larger gun, place the bomb just inside the muzzle, taking care that the bomb does not slide down the bore. DEMOLITION PARTY. A demolition party should consist normally of one noncom- missioned officer and two men. The noncommissioned officer carries two Stokes bombs and one tin of slow fuzes. Bach man carries four Stokes bombs in two sandbags. The men should be practiced in their duties before being sent into action. EMPLOYMENT OF 3-INCH STOKES MORTARS IN RECENT FIGHTING. (Issued by the General Staff, June, 1917.) The following examples of the employment of 3-inch Stokes mortars during recent fighting are published for information : 1. A 4 minutes' barrage was put up preparatory to a brigade attack, with the object of smothering five hostile machine guns. The range was 550 yards, and two ballistite rings and green cartridges were used. The machine guns did not fire and the attack was successful. 2. Twenty rounds were fired by a mortar on a party of Ger- mans who had become isolated, whereupon the party left the trench in which they had been holding out and tried to escape by retiring. Range was rapidly lengthened and some rounds fired over their heads, with the result that they came back and surrendered ; prisoners taken, 2 officers and 70 other ranks. 3. During two counter attacks about 200 rounds were fired at the advancing enemy ; when all their ammunition had been fired the detachment lent effective support to our resistance by using their rifles. 4. A noncommissioned, officer in charge of a mortar observed some enemy working in front of our trench ; by firing over them and gradually shortening range, he drove two of them toward our trench and compelled them to surrender. 5. A mortar was trained onto a party of Germans who were observed trying to get a light Minnenwerfer into position. These scattered at the second round, leaving the gun in the open. Eight carefully registered rounds were fired at the gun and then two bursts of fire. Three direct hits were obtained and the gun was blown up. (197) GERMAN DOCUMENT— PRINCIPLES OF COM- MAND IN THE DEFENSIVE BATTLE IN POSI- TION WARFARE. I. Infantry. Energetic steps must be taken to insist on the infantry in the line continuing their work on their position, even during the fighting. Personal inspection by all infantry commanders, and by the higher commanders, is necessary to insure this. By night, and especially in misty weather, for example, it will often be necessary to strengthen the garrison of the front line or to bring reserves up closer to the front line. In foggy weather a special form of " readiness for action " must be provided for. Gaps between defensive works are a source of danger. They must be commanded by fire from the rear and the flanks, and be kept under observation by the infantry and artillery. By night and in misty weather they should be guarded by outposts. ' The main points to be considered in the stationing of all reserves are to keep them concealed, and to distribute them skillfully over the area, so as to avoid unnecessary losses. Isolated farms, copses, hollows, and roads which lie in valleys, should be avoided, as experience teaches that they are always heavily shelled. When fighting takes place in open country or in positions which afford but little cover, efforts must be made to hold the front line with weak detachments, while the rest of the force is distributed in great depth, as would be the case in a strongly constructed position. When a hostile attack begins with prolonged intense artil- lery preparation by the heavy and heaviest calibers of artil- lery and trench mortars, the foremost trenches are speedily converted into shell-hole positions, in which infantry " nests," composed of isolated groups, are formed round the sentry posts and dugouts, wherever these still exist. It is essential that the men should be trained to connect up such points with each other and with the trenches in rear during pauses in the fighting, by night or during misty weather. (199) 200 The influence of the company and subordinate commanders in fighting in such shell-hole positions often extends only to the men who are actually with them. In such circumstance* stout- hearted men with iron nerves form the real backbone of the defense. All commanders in the front line, senior or junior, must, however, continually endeavor to keep their men capable of offering resistance and ready to make a counter attack by setting a personal example of calm and courageous behavior. In fighting of this character it is no longer advisable to strengthen the garrison of the fighting line and to reinforce it continually. The garrison sustains heavier losses, which are continually recurring and which, because they are unnecessary. are bad for the morale of the troops. The maintenance of the foremost positions, moreover, can not be insured simply by a rigid defense, combined with the reinforcement of the garrison of the front line. To secure this object, tactics of a different character must be employed. The garrisons of the foremost trenches must be weak, but they should not be tied rigidly to one point when they can no longer find cover and may, within certain Omits, change their position in order to escape from a very intense bombardment. Experience shows that no matter how carefully the enemy directs his fire there are points within every area allotted to a unit in which this fire is less effective. It is, therefore, a ques- tion of observing the fall of the enemy's fire and of avoiding the areas in which it is most intense by advancing, moving to the flanks, or falling back on the nearest supports. The best method is to advance, as this is the quickest way of escaping from the enemy's fire. In movements to the flanks or toward the rear to the nearest supports, there is some danger of the continuity of the fire line being broken, and of the enemy establishing small nesfs in it unobserved. Efforts must, there- fore, be -constantly made by the detachments in the shell holes not to lose sight of one another, and the front line must be continually under observation from the rear. If the enemy leaves his trenches to attack our lines. ever\ infantryman must realize that the most certain means of re- pelling the attack are his own rifle tire, hand grenades, and the bayonet, and that even a few machine iruns will hreak up a hos- tile attack. The employment of artillery is a valuable assistance in repelling an assault, hut it is not of itself sufficient to repulse a Strong attack. 201 Every rifle and machine gun which can be brought to bear on the enemy's attack, either from the lire line or from defensive positions in the rear, must he directed against it, in addition to the annihilating and barrage fire of the artillery, trench mortars, and bomb throwers (granatenwerfer). If, in spite of this, the enemy succeeds in entering our trenches, the task of the artillery is to cut him off from the attacking waves and reserves which are following him up, while enfilade and frontal fire (rifle, automatic rifle, and machine gun) is opened on the enemy who has entered our trenches, to prevent his further advance. Trench mortars and bomb throwers, in par- ticular, should be employed to keep the enemy under fire while he is consolidating the position, although the artillery may also take part in this, if observation can be insured. The difficult situation in which the enemy now finds himself must be utilized without waiting for further orders. The de : tachments of the trench garrison who are retiring to the flanks and to the rear, and the supports lying ready behind the fore- most trenches, whose task must have been so drilled into them as to become second nature, must counter attack immediately and recapture the front line. They must in some cases advance under hostile artillery fire. The enemy must be annihilated to the last man by the use of the hand grenade and the bayonet in hand-to-hand fighting. An essential preliminary to the successful employment of these tactics is to make certain that the infantry can observe the fore- ground and the area between the lines. Men detailed to guard particular points (emergency garrisons) do not take part in counter attacks. If the counter attack is successfid, the front line must imme- diately be placed once more in a state of defense, but the garri- son must then be reduced to its previous strength. These tac- tics cause the fighting to take place not in, but for, the front line. It is essential that the men should be thoroughly trained in these tactics, and that the subordinate commanders and men are given clear, precise, and detailed instructions as to what they have to do on the spot. The utmost demands must be made on every man who takes part in the attack. If the garrison of the foremost battle zone is unable to eject the enemy or hold him, a combined attack should be delivered with the general reserve, while the enemy is still engaged in organizing the defense of a strange system of trenches and in fighting the local reserves for "holding on" points, etc. Every 202 man who is fighting in the forward battle zone must realize clearly that by holding out, even if he is completely surrounded, he makes it easier for the counter attack which is certain to be delivered, and is contributing to his own relief. He must, therefore, go on fighting so long as he can use his weapons, The attack jtself should be delivered in waves in extended order, assault detachments being employed at some points. The attack must be supported by the fire of machine guns pushed forward in echelon, by bomb throwers and trench mortars, by infantry guns as well as by the artillery farther, in rear. The success of the attack depends not on the strength of the forces engaged in it, but on the resolution with which it is carried out, the cooperation of all arms, and rapidity of execution. A decisive factor in the success of an attack is the selection of the right moment for the employment of the reserves posted farther in rear. It must be remembered that many requests for support from the front line are, as experience shows, either not justified by the situation or made too soon. If the reserves are alarmed and brought up prematurely, their energy is frit- tered away and the subordinate commanders are tempted to hold the front line with too large a force. If an immediate attack does not succeed in ejecting or anni- hilating the enemy who has entered the position, this can only be retaken by a methodical attack. Reliefs. — The frequent relief of the infantry is undesirable from the point of view both of command and of the troops themselves, as the change prevents the troops becoming familiar with the position and diminishes their keenness in working to improve it. Experience shows that confusion often arises while the relief is being carried out, and ground is lost in consequence. Precautions must be taken, in advance, to insure that there are other communications, which have been reeonnoitered and clearly marked out, to replace routes which have been discov- ered by the enemy and are blocked by his fire. II. Aktiu.kkv. Searching and sweeping fire (unless it can be kept within narrow limits by working with the assistance of suitable regis- tration points situated close to the target, combined with an exact study of the map) and bursts of tire with II. E. shell against groups of the enemy's guns are. as a rule, uselesa 203 the other hand, searching and sweeping fire with gas shell may- be very useful to put artillery out of action for the time being. Gas shell are not suitable for counter battery work which aims at the destruction of the hostile battery. When the trenches are separated by medium distances (about 165 to 220 yards), barrage fire should fall on and close in front of the enemy's foremost trenches, as otherwise the safety of our own trench garrison, which is not to be jeopardized on any account, can not be insured. If the enemy's jumping-off trenches are so close to our own lines that barrage fire would endanger our own infantry, it must be left to the trench mortars, bomb throwers, and infantry to keep them under fire. The artillery barrage fire should then be directed against the enemy's rear- ward positions, in order to cut off his foremost waves of assault from their supports and to catch the latter while they are con- centrating. If the enemy's foremost trenches are farther from our lines (i. e., more than 330 yards), the barrage fire must follow the progress of the enemy's attack. Artillery action against the enemy's tanks is of particular im- portance in the repulse of an attack, in view of the novelty of the weapon and the small amount of experience so far gained. Destructive and barrage fire, which is directed against hollows, roads, and the enemy's positions, will probably often stop tanks by its very intensity, so that only a few will reach or penetrate our lines. Artillery action against these will be carried out by infantry guns and close-range guns which fire with direct laying at short ranges. They are equipped with a special projectile for this pur- pose. It is important that these guns should not open fire too soon, so that they remain concealed and are still in action when they are needed. In addition to these guns, heavy howitzer batteries should be detailed to engage tanks. They will have particular zones allotted to them as targets — i. e., as a rule, strips of ground close in front of our lines which they can keep under observa- tion, and on which they must register when conditions are quiet. If a tank enters the zone allotted to a battery, all the guns should be turned on the tank and salvos should be fired until it is out of action. Nothing but a thoroughly organized bombardment such as this will be successful against tanks. General orders that all bat- teries which observe tanks approaching are to ox^en fire on them only lead to confusion and failure. 204 In exceptional cases heavy. Hat -trajectory guns, fire with direct laying and direct observation, may prove effective, for example, if tanks have hroken throtlgh our linos. Artillery com mauds. — The artillery allotted to armies to rcin- force them for the defensive battle should, in principle, be dis- tributed amongst the divisions in proportion to the importance of the various divisional sectors. Artillery should not he massed; distribution in depth causes the enemy to scatter his fire. III. Air Forces (including Antiaikckai-t I>kiknse). (a) It is necessary to increase the air forces very consid- erably — reconnaissance and artillery aeroplanes, single-seater battle planes, captive balloons, and antiaircraft weapons — be- fore the actual defensive battle, as the first objective of the enemy's attack will be to secure complete mastery of the air. This must be stopped as soon as possible. As soon as the reinforcement of the threatened front is ordered, owing to the situation having become clear and the decision to thwart the enemy's plan having been taken, the air forces and antiaircraft weapons must be further considerably increased. Less important fronts must without hesitation he ruthlessly denuded of aeroplanes, balloons, and antiaircraft weapons. IV. Pioneers. (a) Pioneers are on no account to be employed on tasks which the infantry is capable of performing. (b) The pioneer commander of the division is also in c«.m- mand of the pioneer battalion of the division. The pioneer and minenwerfer companies and the searchlight section of the divi- sion should be under his orders, mid. as a rule, the labor com- panies as well. The divisional commander will arrange lor the command of tlio pioneer and minenwerfer companies and searchlight units, which are temporarily attached to the divi- sion. (c) In a defensive battle, mincnwerler have a special task to perform in engaging tanks. Special zones in front of our lines, which they must be able to keep under observation with certainty, should be allotted to the heavy and medium minen- werfer. in Hie same way OS to i he heavy artillery. If tanks enter these /.ones the minenwerfer concerned will divert their lire from nil other targets and direct it on the tanUs. CONSOLIDATION OF TRENCHES, LOCALITIES, AND CRATERS AFTER ASSAULT AND CAP- TURE, WITH A NOTE ON RAPID WIRING. (General Staff, War Office.) 1. Consolidation of a Captured System of Trenches. The capture of a system of hostile trenches is an easy matter compared with the difficulty of retaining it. A thorough knowl- edge of the principles, a careful study and correct use of the natural features of the ground, and a detailed preparation and organization of the work are necessary ; but success will only result if there is also an absolute determination on the part of all ranks to get the work done promptly at all costs. The principles of the consolidation of captured trenches are, briefly, as follows : (a) To establish a series of strong points or centers of resistance, wired all round and mutually supporting each other according to the ground. These points should be provided with machine or Lewis guns at once. . (&) To provide good communication to the rear from these points. (c) To fill in all hostile trenches within bombing distance of the points occupied. (d) To establish, if possible, simultaneously with the con- solidation of strong points in the front line, a number of sup- porting points in rear. These points should, if the ground is favorable, be placed to cover the intervals between the works in the front line. (e) The strong points can later be connected to form a con- tinuous front line. The above principles must be applied with due regard to the natural tactical features of the ground. The satisfactory siting and consolidation of a position will largely depend on the power possessed by the officers on the spot to recognize during the vari- ous stages of a battle the minor features of real tactical im- (205) 206 • portance. This ability is only acquired by previous training, and is a quality which every officer must study to possess. The size and trace of the " strong points," as well as the intervals between them, will vary according to the lie of the ground and the plan of the hostile trenches captured. During the ]> of consolidation concealment from artillery observation is of importance. The first essential is speed in rendering the captured position strong enough to resist the first counterattacks. It is there- fore necessary that a definite plan should be decided on before- hand as to which points first require attention. This can be done, in the majority of cases, with great accuracy from maps and aeroplane photographs and from a study of the ground from any point in our lines which commands a view of it. In the case of craters the forecast of the tunneling officers must be obtained. Although it is usually advisable that assaulting troops should be relieved as soon as possible, this must not be takes to imply that the duty of securing ground gained is the task only of the relieving troops. It is an unsound principle for troops to expect to be relieved immediately after an attack, as it wastes valuable time at a critical period when speed in work is essential. It must be understood that troops which take a position must com- mence the work of consolidation at once. The distribution of R. E. detachments requires to be carefully considered beforehand. In all cases of an assault or advance, where it is intended to secure the ground gained, the troops destined for the purpose should include a detachment of H. 10., the commander of which should be detailed previously and attached to the staff of the unit or formation concerned. Garrisons must hold on to their ground ; they have nothing to fear from being outflanked. 2. Consolidation of Locai.itii s. During an advance, when it becomes necessary to consolidate some locality of tactical Importance, such as a village or wood, the same general principles hold good as in the consolidation of a system of trenches. Some notes on the particular points that require attention in the case of villages and woods are appended. TILLAGES. Enlargements from even small scale maps give very accurate plans of most villages and make it possible to plan the defense 207 in sufficient detail beforehand. It is essential that subordinate commanders should be provided with such plans in order that the general idea of the defense may be quickly and properly understood. The principles of the defense of a village are laid down in Infantry Training, section 146. The order of urgency of work is as follows : (a) Barricade and picket all exits. Establish center of resistance near exits to cover approaches or any streams or tracks which might serve to guide a counter attack. Com- mence work on keep, preferably at village crossroads. Barri- cade roads. (b) Reconnoiter for cellars. (c) Establish communications, giving cover from view, radiating from keep to outer centers of resistance, and from keep to the rear. (d) Construct bombproofs in cellars at renters of resistance and keep — false roofs to cellars, etc. (e) Complete keep. (/) Improve communications at (c) above, to give cover from fire. {(j) Make lateral lines of communication between centers of resistance. Centers of resistance should be established, if it is possible to do so, to the flank of conspicuous buildings likely to afford good targets for hostile artillery tire. In the case of keeps in villages, this is often impossible owing to the presence of church spires. It is, however, preferable to have a keep, even with this disadvantage, that is central, accessible, and strong against in- fantry assault. It should be remembered in this connection that by the time hostile infantry can assault a village keep hostile artillery fire will necessarily have ceased. WOODS. As in the case of villages, plans should be prepared of the locality. There has been much discussion in the past as to what part of a wood should be occupied. Experience has proved that, owing to the great advantages afforded by cover from view, the position to take up in a wood is just so far within the outer edge as will permit of good view into the open. In this connection it should 208 be remembered that in course of time shell and ride fire thins out the edges of woods considerably. It is therefore advantageous in the first instance to take up positions slightly in rear of those which may appear at the moment to be most advantageous. If, as is often the case, the wood is surrounded by a hedge, there is a natural tendency to make trenches against this hedge. This is to be avoided. A hedge forms a very good obstacle against assault, with the addition of a little wire. If it screens the view, it can be quickly thinned. The order or urgency of work is as follows : (a) Establish centers of resistance for all round defense at the corners and salients of the wood. These are the points which are most liable to counter attack. Establish central re- serve, reconnoiter, blaze, and clear communications. The de- fense of a wood should be very active, and counter attacks must be launched against any hostile troops that may reach the edge of the wood in order to prevent a lodgment that places the enemy on equal terms. (b) Establish intermediate centers of resistance and lateral communications. (c) Establish central keep at junction of rides or on near edge of clearing. In the case of large woods and forests, where the general line of defense runs through a wood, a line of strong centers of re- sistance should be established across the wood, if possible be- hind a road or other clearing. The near edge of the clearing should be entangled, and the intervals between the "centers" should be swept by fire. As time permits "rays" should be cleared, radiating from the centers of resistance and crossing similar "rays" from adjoining centers, so as to add to the depth of the field of fire. These rays should be wired and obstacles arranged, so as to break up an attack and force the attackers into the openings. A line of intermediate centers, communications, etc., should also be established, as indicated in (b) above. 3. Occupation 01 Crati I. The occupation and consolidation of mine craters presents many difficulties, and all ranks should understand the principles to he acted upon in the event of the explosion of mines on their front. 209 II. Craters are usually formed as a result of one of the follow- ing mining operations : (a) An attack by us on the enemy's trenches. (b) An attack by the enemy on our trenches. (c) Underground fighting. III. The possession of a crater offers the following advantages : (a) It can be turned into a strong point capable of holding a small garrison. (5) It gives command of the ground in the vicinity, (c) It forms a considerable obstacle. IV. (a) When mines are exploded by us in connection with an attack on the enemy's trenches, our object should be to seize and hold the wliole of the mine crater or craters or a line in front of them. The latter plan is usually the best, and the craters in rear can then be turned into strong points. (6) When craters are formed as the result of an attack by the enemy on our trenches or in the course of underground fight- ing, our object will usually be to seize and hold the near " lip " of the crater. Parties must be rushed out at once to seize the lip. It may be impossible to open up communication to these parties till after dark. They should therefore take sufficient grenades, water, etc., and must be prepared to hold on though isolated. V. Before the explosion of a mine a forecast should be made of the state of affairs to be expected after the explosion, and all details of probable requirements should be worked out. These would include: (a) The formation of dumps of engineer materials as close up as possible. (&) The organization of working and carrying parties. Work should start immediately after the explosion of the mine, and no time should be lost in turning into account the quiet interval which usually follows the explosion. The personnel of R. E. field companies should be freely used for this work under instructions given through the general staff. VI. The following are the main points to be attended to in the actual consolidation of the craters: (a) All trenches should be strutted as they are constructed. Special frames for this purpose must be made beforehand. (&) All works on a crater, whether inside or outside the " lip," should be provided with a parados. 9784°— 17 14 210 (c) Dugouts should be made by tunneling into the sides and not at the bottom of a crater. (d) At least two communication trenches should be con- structed leading into each crater. Entrances to crat er fl should be made at the sides and not through the rear * lip." (e) All trenches leading up to a crater from the enemy's line should be straightened or filled in for a distance of at least 40 yards from the position of the defenders, so as to keep the * •* * ^L t $ 7rench Main front One enemy bombers at a distance. This work can usually be carried out with the least difficulty immediately after the explosion. (/) Collapsible knife rests. French wire, and other forms of portable wire entanglement should be brought up in large quantities and thrown over the " lip " of a crater. VII. There are two main methods of holding craters: (a) Method A. (See sketch on p. 6 and Plate A.) This method should usually be employed after the explosion by us of a mine in the enemy's t rem lies or in the area where it is known that the enemy is not engaged in mining. 211 The front "lip" of the crater is held by means of several posts. Two communication trenches lead into the crater, one on each side, and give lateral communication between the posts. One or two dugouts are constructed in the sides of the crater. (b) Method B. (See sketch below and PI. B.) This method should usually be employed when the enemy has exploded a mine in or near our trenches, or when we have ex- ploded a defensive mine close to our own trenches. The rear " lip " of the crater is held. Wire is thrown inside the crater. One or two loopholes are cut through the rear * lip " so as to command the inside of the crater. Plate C shows a scheme for converting the area behind the lips of a series of craters, which have been occupied, into a strong post. The importance of rendering the means of access to the lip secure from bombing attack is not always recognized. 212 VIII. Work should be carried out in the following order: (a) Construction of one or two posts in the lip of the crater. (b) Wiring the front of posts and filling in or straightening trenches leading from it toward the enemy. (c) Digging of communication trenches up to the crater. And, if far lip has been occupied: (d) Digging trench for lateral communication inside tin- crater. (e) Completion of wiring front of crater and construction of further posts in far lip. (/) Construction of dugouts. (g) Improvements to the above. It should usually be possible to do (a), (fr), and (c) together. 4. Notes on Rapid Wire Kma.mii.kmknts. One of the first requirements in consolidating a position is to get some wire out in front of it. The following general principles regarding the construction of wire entanglements should be observed : I. The rear edge of the entanglement, should be about 20 yards from the trench; if the trace of the entanglement is Irregular and does not follow the trace of the trench, it will make the task of the hostile artillery more difficult. II. The depth of the entanglement should be as ost> are used rhey must be strong; light posts are useless. 213 VI. The difficulties of crossing an entanglement are increased if it is not too regular ; e. g., if the heights of the posts above ground and the distances between them are varied. For rapid wiring drill, however, a regular entanglement is easier to con- struct. To insure that an obstacle can be erected with rapidity and in silence, every one of the working party must know what he has to do and work so that he does not get in the way of the others. This necessitates some form of drill. There are a large num- ber in use, of which a selection is given on pages 14 to 20. 1 The following notes and rules will be found useful in carrying out any form of drill for constructing wire entanglements : I. The party should, as far as possible, work so that the ob- stacle is always between them and the enemy. Each wiring party should have a double sentry lying down about 30 or 40 yards toward the enemy to prevent patrols sniping or bombing the party. If circumstances necessitate it, a special covering party should be provided. II. The party should work extended and not bunched to- gether. III. Large parties, in which each group of men has only one operation or duty to perform, will erect entanglements quicker than a small party, in which each man has several duties to perform in succession, unless latter is very well drilled. IV. The best unit of entanglement is about 40 or 50 yards long. Its construction can then be controlled from one point. This distance is also a convenient interval to leave small gaps for patrols. V. A line of posts is best laid out at night by putting down a tape or string with the intervals of the posts marked by bits of rag or sandbag tied onto it. VI. The end of a coil of barbed wire will be found secured on the drum tucked under the standing part. In the dark it is very hard to find and release. Coils should, therefore, be prepared by daylight. A good method is to attach a piece of string to the end, uncoil the roll half a turn, re-coil it on a piece of old sandbag, and fasten it up by the string. The end of the wire can then be readily found in the dark. The pieces of tin on the wooden drums should be removed to prevent noise. It may *A French method will be found in Appendix B, " Notes for Infantry Officers on Trench Warfare." 214 be found convenient, to make carrying easier, to re-coil the barbed wire in smaller coils on a stout stake. VII. Pickets should be made up into bundles of one-man loads. They should be firmly tied with plain wire or brought up in sandbags. The latter is the surer way of keeping them to- gether, at any rate with small wooden pickets. A drum of barbed wire is best carried over the shoulder, with a stout stake passed through it, which also serves for uncoiling the wire. Pickets and wire should be clumped by the carrying party out- side the trench behind the center of the length to be wired. VIII. Mauls, if used, should be muffled by nailing on a leather face or with sandbags. About eight thicknesses of sandbag material are necessary to be of any use. IX. Equipment should not, unless necessary, be worn by wir- ing parties, as it is liable to cause noise. X. Stays and holdfasts. (See fig. 1.) Forward stays are not absolutely necessary if the entangle- ment posts are well driven in. They are usually required with iron screw posts, which are not very stiff unless driven in up to the bottom eye. Forward stays can not be put on, without great loss of time, until the fence on the first row of posts has been completed, for they would interfere with the fence wire being looped aver the posts. Back stays should invariably be provided and anchored well back, so as to resist any attempt to pull the entanglement away by grapnels. Side stays at the ends of separate lengths of entanglement are usually desirable. Pickets used as holdfasts for stays should be " staggered " — i. e., not driven in vertically, but inclined away from the post that they stay. XI. When stringing horizontal wires for an apron on a stay or diagonal, the latter should be given a kink or bend at ibe places of crossing, so that there will be less chance of the wires slipping down. The horizontal wires may be secured by bind- ing wire or by taking a bight and looping it around the stay. The coil should not be passed over and under, as tbis la a slow- process. NOTES WITH REFERENCE TO IRON SCREW POSTS AM) PICK J (a) Tbe posts jire 5 feet long with four eyes, tbe pickets two 3 feet 6 inches long With two eyes, or 15 inches long with a 215 loop at the end. If the ground is soft the posts can be screwed in 2. feet deep or more. 1 (b) In rapid work the wire can simply be placed in the eye by forming a loop in the wire and slipping it over the post. It is not intended that the wire should be threaded through the eye. If time allows, the horizontal wires can be put on slack, and when the fence is strung the post can be given a complete turn so as to prevent the wire slipping out should it be cut, or the barbed wire may be twisted round the posts, through an eye, as it is put on, or it may be secured to the eyes by binding wire. (c) To permit of the loops being slipped over the posts, it is obvious that the lowest wire in a fence must be put on first, and no forward or back stays can be fixed until the fence has been completed. (d) Care must be taken that all the posts are originally screwed in so that the eyes point the same way ; otherwise de- lays will occur in the wiring. (e) Loose bundles of iron screw posts and pickets can not be carried noiselessly. It is advisable, therefore, to wrap them round with a sandbag, secured by a light turn of wire, with the ends twisted together. Enough end to this wire should be left so that it can be untwisted by hand without pliers. (/) Short stakes or bats must be provided to fit the top eye of the posts in order to screw them in. The helves of the in- trenching implement serve the purpose. Examples of Wire Drills. Picket is used to mean a short picket used as a holdfast. Post is used to mean a longer upright. Fence is used to mean a series of wires on a row of posts. The conventional signs used in the diagrams are explained in figure 2. In all the drills given, unless otherwise stated, it is assumed that— (a) The length to be erected is 50 yards. (b) The stores required are collected at a point behind the center of the length in a convenient order. (c) The line of the fence has been marked or indicated. iAngle-iron posts are 5 feet 10 inches and 3 feet 6 inches long. 216 (d) The drums of wire are opened and the ends ready. (e) Bars or sticks are rim through the drums so that the wire can be uncoiled readily. (/) Short sticks for screwing in the pickets arc carried by the men requiring them (or mauls if wooden or angle iron pickets are used). (//) All wirers have hedging gloves and wire cutters, and have their legs protected by gaiters or sandbags. (h) Each number consists of two men, who work together, and the numbers commence work in succession at a suitable in- terval (say, four posts apart). Thus Nos. 2 move off as soon as Nos. 1 have the desired start ; Nos. 3 at the same interval behind Nos. 2. (i) All work is commenced on the left. 0') The men who put the top wire on a fence stay the end post to short pickets. ( A) On completion of each operation or " duty " detailed in the drill, all men should return to a fixed place, in order to prevent confusion, if some work faster than others. (I) Spare men are at hand to replace any casualties. The drills are primarily intended for use with iron screw poets, but can be used for wooden or angle iron posts with slight modi- fications. If the soil permits of posts being screwed into the bottom eye, no stays are necessary, and three horizontal wires in the fence, instead of four, will be sufficient. No estimates of stores required are given, as the distance apart of the posts and the amount of wire used must depend on what is available. DRILL NO. 1. DOtTBLB-APRON ENTANGLEMENT. [See fig. 3.1 Working party, 12 men, exclusive of noncommissioned officers. First duty. Nos. 1. Lay posts in position on ground A. N (Front rank— assists Nos. 1. 'jltoar rank holds up posts for Xos. .'{ t<> si row in. Nos. 3. Screw in posts, separately. Nos. 4. Lay front and roar pirkets in position. Nos. 5. Screw in front pickets B. Nos. G. Screw in rear pickets C. 217 Second duty. Nos. 1. Bottom wire of fence A. Nos. 2. Second wire of fence A. Nos. 3. Third wire of fence A. Nos. 4. Top wire of fence A. Nos. 5. Front diagonal between A and B. Nos. 6. Rear diagonal between A and C. Third duty. Nos. 1. Top horizontal wire on front diagonals A B. Nos. 2. Second horizontal wire on front diagonals A B. Nos. 3. Bottom horizontal wire on front diagonals A B. Nos. 4. Top horizontal wire on back diagonal A C. Nos. 5. Second horizontal wire on back diagonal A C. Nos. 6. Bottom horizontal wire on back diagonal A C. This drill involves Nos. 5 in " second duty " and Nos. 1, 2, and 3 in " third duty," working in front of the fence. In the " first duty " No. 2 rear rank holds up a post for No. 3 front rank to screw in until it gets a bite in the ground. He then holds up a post for No. 3 rear rank, etc. This obstacle and others of the same nature can be deepened by adding similar bays behind it. The posts in successive bays should cover the intervals between those in front of them. (See fig. 4.) If two bays are made, the obstacle can be increased by tossing loose wire into the valley between the posts. DRILL NO. 2. TRIP, FENCE, AND APRON. (See fig. 5.) Working party, 10 men, exclusive of noncommissioned officers. First duty. Nos. 1. Lay posts in position A. Nos. 2. Hold up posts. Nos. 3. Screw in posts. Nos. 4. Bring up and screw in front pickets B. Nos. 5. Bring up and screw in rear pickets C. 218 Second duty. Nos. 1. Front trip wire on pickets B. Nos. 2. Bottom wire on fence A. Nos. 8. Second wire on fence A. Nos. 4. Third wire on fence A. Nos. 5. Top wire on fence A. Third duty. Nos. 1. Front diagonal between A and B. Nos. 2. Back diagonal between A and C. Nos. 3. Top horizontal wire on the diagonals A C. Nos. 4. Second horizontal wire on the diagonals A C. Nos. 5. Bottom horizontal wire on the diagonals A C. Nos. 1. Have to work in front of the fence in M third duty." DBILL NO. 3. TRIP AND FENCE. (See fig. (5.) Working party, 16 men, exclusive of noncommissioned officer First duty. Nos. 1. Screw in posts 6 feet apart, A. Nos. 2. Screw in pickets B and C ; B first. Nos. 3. Trip wire B. Nos. 4. Bottom wire of fence A. Nos. 5. Second wire of fence A. Nos. 6. Third wire of fence A. Xos. 7. Top wire of fence A. Nos. 8. Diagonal wire between A and C. Second duty. Nos. 1. Diagonal wire, between A and B. Nos. 2. Trip wire G. x* S a \ Uncoil loose wire. Nos. 4. J _ . . ' I Toss in loose wire uncoiled. Nos. 6. J •«' ) Xos. 7. . „ \ Fasten loose wire. In the "second duty," Nos. 1 have to work in front of the fence. 219 Nos. 3 and 4 uncoil the loose barbed wire on the ground well clear of the entanglement. Six coils for each 25 yards. Nos. 5 and 6 with large wooden pickets lift the loose wire and toss it on to the entanglement. Nos. 7 and 8 spread the loose wire out and fasten it by twist- ing a bight at intervals to the diagonals and fence wires. DRILL NO. 4. FENCE, WITH CROSSED DIAGONALS AND TRIPS. (See fig. 7.) Working party, 14 men, exclusive of noncommissioned officers. The pickets are placed opposite the posts. This drill involves four men working on the enemy's side of the fence. First duty. Nos. 1. Screw in posts A. Nos. 2. Screw in pickets, B first, then C. Nos. 3. Trip wire B. Nos. 4. Bottom wire of fence A. Nos. 5. Second wire of fence A. Nos. 6. Third wire of fence A. Nos. 7. Top wire of fence A. Second duty. ' * I Prepare posts in next length. Nos. 3. Front diagonal between A and B, commencing at picket B, Bj, then to A 2 , B 3 , etc. Nos. 4. Front diagonal between A and B, commencing at top of post Ai, then to B 2 , A 3 . Nos. 5. Back diagonal between A and C, commencing at picket Ci, then to A 2 , C 3 , A 4 , etc. Nos. 6.1 Back diagonal between A and C, commencing at top Nos. 7. J of post Ai, then to C 2 , A 3 , etc. DRILL NO. 5. SUCCESSIVE ROWS OF FENCES. (See fig. 8.) Working party, 12 men, divided into four groups of 3 each, W, X, Y, Z. The posts must be prepared by attaching binding wire to the bottom eye, to this the vertical diagonals between the fences are made fast. 220 First duty. Group W. Lay out posts in row B. Group X. Screw in above. Group Y. Lay out pickets in row A. Group Z. Screw in above. Second duty. Group W. Lay out posts in row C. Group X. Screw in above. Group Y. Bottom wire of fence B. Group Z. Trip wire on row A. Third duty. Group W. Second wire on fence B. Group X. Third wire on fence B. Group Y. Top wire on fence B. Group Z. Front diagonal between A and B. Fourth duty. Group W. Bottom wire of fence C. Group X. Second wire of fence G. Group Y. Third wire of fence C. Group Z. Top wire of fence C. Fifth diitfi. Group W. Diagonal between B and C, bottom of d to top of Bi, bottom of C 2 , etc. Group X. Second diagonal between B and 0, top <»f Ci to bottom of Bi, top of C 2 , etc. Group Y. Lay out and screw in pickets 1>: or lay out row of posts D, if the fences are to be continued. Group z. Diagonal between G and l>: or screw in above, etc In "third duty" Z and in "fifth duty " \Y and X work on enemy's side of fence. In "fifth duty" W and X loop the diagonals over top of pickets and make them fast to the bottom eye by binding wire. Instead of putting the criss-cross diagonals between fences B and C as above, which involves binding wire and takes some 221 little time, it would be sufficient if time presses to stay the pickets merely by connecting the heads. (See fig. 9.) " Goose- berries," etc., can be thrown into the space between B and C. Another variation is to put loose wire or French wire between fences B and C and criss-cross plain wire to connect the tops of the pickets. (See fig. 10.) A further variation can be introduced by placing the posts so as to form squares instead of triangles. (See fig. 11.) DRILL NO. 6. DOUBLE FENCE, (See fig. 12.) Working party, 28 men, exclusive of noncommissioned officers. This entanglement is designed for stout wooden posts well driven in or screw posts screwed in down to the bottom eye ; no hold-fast pickets are then required. The drill only requires one duty from each pair of men. The apron is of a different pattern to those previously given ; the wires miss alternate pickets. Three horizontal wires can be used for the fence instead of the " gate " pattern shown. Order of work. Under superintendence of two noncommissioned officers, all hands carry up and place the posts on the ground. No. 1 drive or screw in posts in front fence A. No. 2 drive or screw in posts in back fence B. No. 3 bottom wire 3 of fence A. No. 4 diagonal wire 4 of fence A. No. 5 diagonal wire 5 of fence A. No. 6 top wire of fence A. No. 7 bottom wire 3 of fence B. No. 8 diagonal wire 4 of fence B. No. 9 diagonal wire 5 of fence B. No. 10 top wire 6 of fence B. No. 11 apron wire 11. No. 12 apron wire 12. No. 13 apron wire 13. No. 14 festooned wire 14. 222 DRILL NO. 7. ORDINARY LOW ENTANGLEMENT. 1 (See fig. 13.) Working party, 30 men, in 10 groups, with a noncommissioned offier. Group A, front row of pickets A. Group B, straight wire A row of pickets. Group C, second row of pickets C. Group D, zigzag wire Ai, Ci, A 2 , C 2 , etc. Group E, loose wire on zigzag Ai, Ci, A 2 , C 2 , etc. Group F, straight wire on C row of pickets. Group G, third row of pickets G. Group H, zigzag wire Gi, Ci, G 2 , C 2 , etc. Group J, loose wire on zigzag Gi, C* G% C* etc. Group K, straight wire on G row of pickets. Pickets may be 12 to 18 inches out of the ground and 3 feet apart. DRILL NO. S. FRENCH WIRE OBSTACLE. (See fig. 14.) The obstacle consists of two rows of French wire, placed just far enough apart for a man to pass between them. Each coil is stapled down in five places — at each end, and at one-fourth, one- half, and three-fourths of its length. When two coils meet, the same staple fastens down both coils. Posts 5 feet long are driven through the center of the coils in five places, as in the case of the staples; the ends of adjoin- ing coils are interlaced a little so that the post will go through both. A strand of barbed wire is run along the top of each row and fastened to the posts with a round turn. It is pulled as taut as possible and twisted on to the French wire by a Staple, veg, or wire cutters, close to each post, and in several places between the posts. One or more strands of bnrbed wire are run along to the front as an " apron." Diagonal wires are run from the tops of posts of the front row to tops of posts of second row. Working party, 24 men in three parties, with noncommissioned officer. *A low entanglement Is not, as n rule, sufficient by itself but may be combined wjth a high entanglement. (See figs. 15, 16, 17, 18. 223 Front row. Party A. 1 holds end of French wire and staples it down; 2 pulls wire out 20 yards ; 3 shakes wire clear of obstructions and put in staples one-fourth, one-half, and three-fourths way long. Party B. 1 mauls in anchorage pickets and posts; 2 holds posts ; 3 supplies posts. Party C. 1 uncoils barbed wire ; 2 makes fast end to anchorage and twists wire round tops of pickets ; 3 twists barbed wire on to the French wire. Party D. 1 runs coil of barbed wire along the front ; 2 and 3 twist it onto the front of the French wire. Back row. Party E. Same as A. Party F. Same as B. Party G. Same as C. Party H. 1, with coil of barbed wire, moves between the two rows, uncoiling the wire ; 2 and 3 move on either side of the en- tanglement and make this barbed wire fast to the posts as the diagonal, while Hi holds the coil so that H 2 and H 3 can reach it. The obstacles described above can be combined in various ways either by placing one behind the others (see figs. 15 and 16) or by placing a high wire entanglement over a low one (see figs. 17 and 18). Plan Plate A. Sketch of Front Lip of Crater prepared for defence. Plan. 225 4JJ, *D784< 22(3 Plate B. Sketch of Bau Lip of Crater prepared for defence. •Cteervat-'O/i Ti/n/ie/ OjssrrottOf) r u nr>tt 227 CO < z o z o < > HI _J UJ < z o H o UJ CO OQ M o I l(Jvtsj Cj '4DV3*u uC^i^OOninaiLuoj 228 229 Fig. 1. Sack Sfixy Section. S/c/e S/ac/y^ -• — * — * *- 1* — * j* — * — n- -*- -*- ^^ -* — * — « — * — -*— Elevation. 230 Pig. 2. Conventional Signs used in Plates, Plan. Elevation. Posts (long). Q Pickets (short). # In fence. 1 Horizontal Wire. 2 Horizontal Wires. 4 Horizontal Wires. ++ TV ^wmwwwww fr/* imm7^777^777$M^ V/W/zW/VW/W/AvfrfT/c Top end. Inclined Wire. Gate. Gate and 2 Horizontal Wires. W)&W*&JUWV/®W&> 231 Fig. 3. Fig. 4. oooooooo oooooooo 232 •>* / rV O Fig 7. J*— tf-r-y D *> /x v£v 233 Fig. 8. Fig. 9. Fig. 10. 234 Pig. 11. Elevation or A and B. Fig. 13. 235 Pig. 14. 9—* n w n » — * — ,0*er/ap of French l/V/re. -Top Barbed Wire — \/ \ . — ^«_* 0/aponctf tV/re Pig. 15. Pig. 16. French W/ne ■*—** — * — * — #- Combined High and Low Entanglements. 236 Pig. 17. i Fig. 18 NOTES AND RULES FOR BARRAGE FIRE WITH MACHINE GUNS. (Issued by the General Staff.) DEFINITIONS. A barrage of fire produced by machine guns is intended pri- marily to deny a certain area of ground to the enemy by prevent- ing him crossing one or all of the lines which bound it. A bar- rage, therefore, may be frontal or flanking (with regard to our own line), or both simultaneously. Figure -Frontal barrage. ENEMY E.- A.- + __ 111 _ ill ill _ ill l|l i|r l|l i|i (237) 288 Figure II.— r-Obliqur barrage. ENEMY. 1 1 i I,' ' s / s /■ / s s y / s * ' * ' ancle- or obliquity. EMEMY. Figure III. — Flank barrage. D. m a. TJie production and application of the integral parts of a barrage — i. e., of the conaecutlTe zones from the gone eftfagMfr - present DO now problems at all. The ordinary methods of tiro direction tor engaging a visible or an invisible target apply with no modification whatever. 289 GENERAL NOTES. (a) Limits of front each gun can cover : There is a lower limit and an upper limit to the front which each gun can cover in producing a barrage. The lower limit will produce a barrage of high efficacy, com* parable In effect to a dense artillery barrage, which should cause (on flat ground) somewhere about 50 per cent casualties to a hostile body of troops passing through it. The upper limit produces the minimum thickness barrage which can be applied conveniently without gaps. These two limits really define the opposite ends of a scale between which the machine-gun officer can operate, choosing whatever degree of efficacy of barrage he may consider necessary to meet the tactical situation, or to produce the most efficient barrage with the number of guns at his disposal. (&) As a rough guide, the number of rounds to be fired per burst may be taken as twice the first two figures of the range in yards. Example : Range, 2,100 yards ; 40-round bursts. REMARKS. This type of barrage, produced by using the upper limit, might b» required, for instance, to stop definitely any attempted enemy counterattacks, etc. This type of barrage might be employed when it is required to deter the enemy from manning parapets, escaping over the open, or making use of any particular area of ground, etc. RULES. Rule I. For frontal barrage. Lower limit is obtained by multiplying the gradient of descent of the bullet at the range at which the barrage is being produced by 4. Uppei limit : Seventy yards for all ranges. Example : Range is 2,100 yards. From Table I, column 3 (vide Infantry Machine-Gun Com- pany Training), gradient of descent, 1 in 5.5. Lower limit = 4 X 5.5 = 22 yards per gun. Upper limit = Y0 ; -ards per gun. 240 Rule II. For obVique barrage. Lower limit Is obtained by multiplying the gradient of descent of the bullet at the range at which the barrage is being produced by 4. Upper limit: For all ranges, 70 yards plus 2 yards for each degree of obliquity (vide fig. II) up to a maximum of l-~ii> yards, which must not be exceeded. Example: Range, 2,100 yards; degree of obliquity. From Table I, column 3 (vide Infantry Machine-Gun Cora* pany Training), gradient of descent, 1 in 5.5. Lower limit = 4 X 5.5 = 22 yards per gun. Upper limit = 70 -f(2 X 45) = 70 + 90 = 160. This is over 150, therefore 150 yards must be taken. NOTES. On Rule I. For frontal barrage. (a) Traversing must be employed, but there is no advantage gained by searching if only a curtain of fire is required. (b) If the ground slopes down and away from the guns, both limits may be increased, and vice versa. On Rule II. For oblique barrage. (a) Traversing must be employed, but there is no advantage gained by searching if only m curtain of fire is requited. {b) If the ground slopes down and away from the guns, both limits may be increased, and vice versa. RULES. Rule HI. For ftank barrage. In this case the limits become the actual difference! in sighting elevation to be used on the guns. Lower limit is obtained by multiplying the gradient of de of the bullet at the range at which the barrage is being produced by 4. Upper limit. 150 yards for all ranges. Example: Range to nearest zone, 2.100 yards. From Table I, column 3 (vide Infantry Machine-Gun Com- pany Training), gradient of descent, 1 in 5.5. Lower limit = 4 X 5.5 = 22 yards. Upper limit = 150 yards. 241 I. e., for high efficacy, combined sights with 25 yards differ- ences; for thin but continuous, 350 yards differences. Rule IV. Only for ranges below 1,300 yards. Use the upper limit only, as given in Rules I, II, and III, for all ranges below 1.300 yards. Example : Range, 1,200 yards ; frontal barrage, front, per gun, 70 yards. NOTES. On Rule III — for flank barrage. • (a) It should be observed that the danger line, through which an enemy has to pass, is much less in thickness in flank than in frontal barrages, as in the latter case we are dealing with the width of the zone, whereas in the former we are concerned with the depth. Therefore it takes a much shorter time for a man to pass through, and this emphasizes the necessity for continu- ous fire in flank barrages. As the number of guns required is not excessive, and others may, therefore, be available, if a high degree of protection is de- sired, a second barrage should be formed, parallel to the first, with, say, 50 yards separating them. The two should not be superimposed, because if by reason of any ground formation or artificial cover a part of the ground was defiladed in the first barrage, it is probable that such defilading effect would not exist at the same distance from the guns and a little way to a flank. In other words, gaps formed as indicated above in both barrages would probably be staggered, thus rendering the combined bar- rage continuous throughout its length. (6) It should be noted that the rules for "combined sights" do not apply to this type of fire, e. g., in this case differences of 25 yards or 150 yards are permissible. On Rule IV. Reason : That although the rule for obtaining the lower limit is theoretically correct, it gives large frontages, which each gun can cover when the range is below 1,300 yards. The influence of ground (i. e., slight obstacles, undulations, etc.) here becomes so great that it is not advisable to use such large frontages. 9784°— 17 16 242 MODIFICATIONS DUE TO KATE OF EIRE, SPEED 01 HOSTILE \!>YANCK, ETC. (a) The rules given are applicable without alteration to all cases where the ratio — Rounds fired by each gun in one minute 1 . pmiil to 4 1 Speed of enemy advance in yards per minute/ q T (&) If each gun is firing 300 rounds per minute (about its maximum), the rules then will apply for a speed of advance of about 2$ miles an hour. (c) If the pace, owing to bad ground, etc., is less (than 2* miles per hour), then each gun can lire fewer rounds per minute and still produce the same degree of efficacy of barrage. (See example. ) (d) If you have fixed beforehand the number of rounds to be fired by each gun per minute, and if you have estimated the probable speed of advance, the ratio (see No/1, above) will show you how to modify the rules to meet any particular case. (See example. ) REMARKS AND EXAMPLES. (a) The factor 4. which is given in the rules, is a good safe figure to use and should be used in all cases where there is no time to make further calculations. (b) For example, 2£ miles an hour = about 75 yards f 3001 ■* per minute \ 75 J (c) e.g., speed of advance, estimated at not more than 11 miles an hour, owing to mud, etc., this equals 44 yards per minute. Number of rounds to be fired by each gun per minute can therefore be found : Number of rounds per minute , « 44 /"*• I. e., number of rounds per minute =4X44 174 <<>r there- abouts). ( create gaps in our own ohstaeles, will he exploded by the engineers at the earliest 15 minutes before the flame attack, and this work must he com- pleted 10 minutes before the flame attack. It will often he found sufficient if, on the night previous to the attack, the engineers cut the wire winch connects the knife rests in front of the foremost trenches. This must he done without attracting attention, the knife rests being left in their original position until the troops are ready to attack — i. e.. Immediately after the flame attack — when the engineers will precede the assault- in- force, swinging the knife rests round lengthwise at right angles to the parapet Engineers will also hurry forward and make gaps in the enemy's wire, should these not have been made previously In- trench mortars or engineer detachments. Obstacles which are not too strong can very often he easily crossed by the assault- 249 ing troops, as after a flame attack the enemy fires very little or not at all. 31. The duration of the flame attack is only one minute. The signal for it is given by a siren whistle, or at a given time, watches having been previously synchronized. The assaulting troops must be instructed that they have nothing to fear from the flames and smoke, nor need they fear that they may them- selves be caught by the fire jet, as this is cut off by simply turning a tap previous to their advance. They must understand that they can advance immediately after the cessation of the spray without danger, as small bursts of flame on the ground or in the enemy's trenches will burn out at once, and a little fire on the ground is at once extinguished when trodden upon. It is most important to impress upon the troops that the assault is much facilitated by the use of the flame projector, as it has been proved by experience that the enemy fires very little or not at all after a flame attack. 32. The assault is made immediately after the flame attack. The assaulting party charges, followed closely by the consoli- dating party. The small flame projectors allotted to the as- saulting party attack any machine guns that are still in action, blockhouses that are still being defended, etc., with short spurts of fire. They are at the disposal of the commander of assaulting party for this purpose. It is of the highest importance to drive out the enemy simul- taneously to a considerable distance on both flanks by means of bombing and flame-projector detachments (see par. 22) and to construct sandbag barricades at these points. Communication trenches which lead into the captured position must also be cleared for a certain distance and blocked by constructing sand- bag barricades about 27 yards forward of the position won. The action of the communication-trench construction party will commence immediately after the nearest enemy position has been taken. Material is brought up as soon as possible by the carrier party, which will continue to bring up fresh material from the rear as required. Carrier parties can at times on their return journey also take charge of prisoners as far as the point at which the reserves are situated in rear. It is especially important to bring up and dig in machine guns immediately. 33. It may be of advantage to order a password for our attacking troops, especially if several successive positions are 250 to be taken, and in the twilight of dull days. Words which ihe enemy would find it difficult to pronounce are particularly suitable, such as " Schweineschmalz," M Stief elwichse," etc. (vi) Action of the artillery and trench mortars. 34. In a flame attack pure and simple, which is generally to be preferred (see par. 12), the action of the artillery and trench mortars will not commence until about one minute after the projection of the flames, when the more retired positions, which it is not intended to take, should be shelled. Barrage fire will be opened on the ground behind these positions and on the communication trenches, etc. 35. Should it be impossible, in exceptional circumstances* tO dispense with previous preparation by the artillery and trench mortars, only the enemy's rear positions, and not his foremost, positions, are to be shelled. It does not matter if this results in the enemy pressing forward into the positions nearest to us in order to obtain shelter, thereby, reinforcing the garrison. It must, however, always be borne in mind that by artillery and trench mortar preparation the enemj is warned of an im- minent attack, and is thus enabled to take precautionary meas- ures. 36. In most cases, however, it is advisable to request the divisions on the right and left to open with artillery on the enemy's rear positions behind the front which it is intended to capture. Registration must be carried out so as not to attract attention. 37. As a rule it is advisable to detail a special artillery group to repulse hostile counter attacks. Its commander must take up his position with the commander of the attacking force and must arrange for special telephonic communication. (vii) Forces on tin flunks of the froni of attack. 38. The effect of a flame attack is sometimes felt to the right and left of the front which is covered with tlame. Our troops which are posted on the Hanks of the actual front of attack can sometimes, therefore, gain ground by a prompt ad- vance in force, ii is. consequently, necessary to beep under close ohseiwation Ihe enemy's troops on the thinks of the front of attack, and, according to circumstances, either subject them 251 to a heavy fire or attack them as well. Engineer detachments are to be posted in readiness for forming gaps through the ob- stacles, should this be necessary. (viii) Equipment, ammunition, and rations. The assaulting troops will wear " assault order." Each man will take his great coat, tent square, mess tin, full water bottle, four days' rations in his haversack, and, in addition, at least 200 rounds, two hand grenades, and rifle with fixed bayonet. The consolidating parties are similarly equipped, except that they sling their rifles (bayonets not fixed). Each man will carry a loophole plate, 50 sandbags, and heavy entrenching tool. Communication trench and carrier parties will appear in their usual order of dress. Only the noncommissioned officers will carry rifles. The men of the communication trench party will each carry a heavy entrenching tool, 50 sandbags, and at least two hand grenades. * (ix) Telephone eommunieations. 40. A number of infantry telephone lines will be laid from the captured position to the rear immediately after the assault. 47. All lines leading to the commander of the attacking force are to be used solely for service messages which concern the attack, so that he can bring his personal influence to bear upon every part of the front. Additional Remarks by Fourteenth Reserve Corps. (Fourteenth Reserve Corps headquarters, la No. 629, secret, dated Apr. 28, 1916.) On March 23, 1916, attention of the divisions was called to the fact that information had been received from the Moritz listen- ing apparatus as to practice by the British with flame pro- jectors and lachrymatory bombs ( corps headquarters, la No. 4.51, secret, dated Mar. 23, 1916) . During the raid against the Ninety- ninth Reserve Infantry Regiment on the night of April 22-23, 1916, lachrymatory bombs were employed. The enemy continues to practice with flame projectors behind his front. Moritz listen- ing post No. 52 reports on such a practice for the 29th of this month. It is quite possible that the enemy intends shortly to use this weapon against us. Whether he will combine his flame 252 attack with artillery fire is doubtful. It is not absolutely necessary. The troops are to be instructed as to the special features of This new weapon (corps headquarters la No. 1506, secret, dated Dec. 19, 1915). Flame projectors which have been built in in the enemy's positions (see par. - of the above-mention 202 Main Library LOAN PERIOD 1 HOME USE ALL BOOKS MAY BE RECALLED AFTER 7 DAYS Renewal, and Recharges may be made 4 days prior to the doe date. Books may be Renewed by calling 642-3405. SEPl 1988 DUE AS STAMPED BELOW auto oisasEP 01 BJ FORM NO. DD6, UNIVERSITY OF CALIFORNIA BERKELEY BERKELEY, CA 94720 VB 47996 GENERAL LIBRARY - U.C. BERKELEY B0D03132ME 667G13 (Ji: UNIVERSITY OF CALIFORNIA LIBRARY