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Price 6d SIEGE 1901. Price 9d ARTILLERY. FIELD. Tactics of. 1897. Price Is. ARTILLERY. MUSEUM. In the Rotunda, Woolwicli. Catalogue of. 1889. Price Is. 9rf. ARTILLERY KIT PLATES. Nos. 1 to 10. Price 2J. each. ARTILLERY AND RIFLE RANGES ACT, 1865. Bye-laws made by Her Majestj^'s Principal Secretary of State for the War Department, with the consent of the Board of Trade. 8vo. Price \d. each :— Aldeburgh. Ash, Aldershot Camp. Hj'the. Inchkeith Battery. Kinf^hornes?. Landguard. Finborough. Lydd. Middlewick. Millbrook. Orchard Portman (1897). Paull Point Battery, Salisbury Plain (price Mi.). Scarborouf(li (189.^). Scarborough Artillery (1902). Scraps Gate. Shoeburyness. Southwold, Strensall. Warden Point Battery and Hurst Castle. Wash. Whitehaven Batt«ry. Cumberland. ARTILLEAY. ROYAL REGIMENT OF. Standing Orders of the. Nove.-nbpr, 1893. Price 2s. ARTILLERY STORE ACCOUNTS. Notes on. Price 6c?. ELECTRICITY. Notes on. For the use of the Garrison Artillery. By Lt.-Col. .1. R. J. JoCKLYW, R.A. Price Is. U. ENGINEER SERVICES. Regns. for. 1900. Price Is. 6c?. ENGINEERING. MILITARY. Instrviction in. Compiled at the School of Military Engineering, Chatham. Svo. Cloth. Part 1.— Field Defences. Seventh Edition. 1902. Price Is. 6cZ. Part 2.— Attack of Fortresses. Fifth Edition. 1896. Price Is. .3q!. Part 3.— Military Bridging and Use of Spars. Fourth Edition. Corrected to January, 1902. Price Is. 6rf. Part 4.— Mining and Demolition. Fifth Edition. 1901. Price Is. 6rf. Part 5.— Miicellaneous. Fifth Edition. Price Is. M. Part 6.— Military Railways. Price 4e 9c/. 4-7-inch a.F. (Fixed Armaments.) Land Service. 1904. Price Is. 4-7-inch Q.F.B. (Mark IV.*) on Travelling Carriage. Land Service. 1904. Price Is. 4-inch B.L. (Marks V. and VI.) (Land Service.) 1904. Price Is. 2-9!i-inch Q.JT. Mountain Gun. (Mark I.) Mule Equipment. 1901. Price 'M. 0-303-inch and -SOS-inch Converted Maxim Ma ine Gun. (Magazine Rifle Chamber.) 1903. Price \s. 64-PR. 40-PR. 20-PR. 15-F«. 15-PR. 13-PR. 121-PR. 12-PR. 12-PR. 10-PR. 6-PR. 3-PR. Hotchkiss. a.F. 6-PR. Nordenfelt. a.F. 3-PR. Nordenfelt. a.F. 12-5-inch K.M.L. 38 ton. 6-inch 6-inch 6-inch 6-inch [All Rights Reserved. 40 W.O. MANUAL OF MILITAET EMlNEEIll]\Tx GENERAL ST^FF, AVAR OFFICE. LONDON : FEINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HAEEISON AND SONS, ST. IMAETIN'S LANE, PEIITTEES TS OEDINAET TO HIS MAJESTY. And to be purcliased, either directly or through any Bootsellei', fronx WYMAN AND SONS, Ltd., Fetter Lane, E.G. ; or OLIYER AND BOYD, EDi>-BTTEaH ; or ^ E. PONSONBY, 116, Geaftox Sireet, Dublin. 1905. Price One Shillin'j. 4 2 dt,^^ ?< a. '•-"'V^^ sXyJ\j^. L\^ / ^ y r^ (^w^ 35.000 nf^-R^mi^^_^ ^, ^.,^ ^ '^^-^ ^'T^ ManuaMs issued by comnandoTSSe^my Council for the guidance of all concerned. --ico^fUzM^ War Office, 8/A August, 1905. (5289) A 2 CONTENTS Chapter. Subject. Page. I. IT. ITT. IT. y. YI. YIL VIII. IX. X. XI. XII. XIII. XIV. XV. XVI. XVII. XVIII. XIX. XX. XXI. XXTI. XXIII. PAET I. Peeltaitnabt ElELD GeOMETUT . . lNTRE>^CHiyG^ T03LS WoEKiNG Parties and Execution of In- trench5ients Materials . . Retetiments . . Clearing the Foreground Improvement of existing Coyer, Stockades, &c. .. Earthworks. . Obstacles Defence of Posts, Villages and Camps Temporary Eoads .... Knotting AND Lashings.. Military Bridges. . Camping Arrangements.. Hasty Demolitions with Explosives., „ Demolition of Railways and Tele- graphs without Explosives PART II. Strength of Materials and Buoyancy Blocks and Tackles — Use of Spaiis .. Erame and Cantilever Bridges, Framed Trestles, Suspension Bridges, and Cask Piers Demolition Eoemulje and Working Party Table, &c. Roads— Boning and Levelling Railways and Telegraphs G-LOSSARY OF TeRMS Index 5 10 12 14 17 23 25 26 31 41 44 51 52 55 68 78 96 101 107 109 lis ]2S l;{7 ]40 MMUAL OF MILITARY ENGINEERING. (^Tliis book is divided into two parts. Officers should he ihoroughly acquainted with the matter dealt icith in Fart I. Part II contains information useful for reference. The types of the various works described will vary according to the conditions of time, labour, and material. Officers and Non-commissioned Officers in charge of luorks should, while bearing the principles in mind, learn to modify the types according to local conditions.') CHAPTER I.— PRELIMINARY. {See also " Combined Training," 1905, Section 123, and following sections.) 1. The object of fortification is to strengthen ground, and by Objects o! thus economising the numbers of the defenders, to swell the fortifica- force available for offensive movements, by which alone ^^°^' decisive results can be obtained. This object is secured by fulfilling, as far as possible, the following conditions : — (a) The position to be defended must be chosen with due General regard to tactical requirements, and with a view P^iiiciples. to economising men ; its strong and weak points must be carefully studied. (6) The enemy in attacking should be exposed as much as possible to the fire of the defenders during the advance. To this end the foreground may require more or less clearing, (c) Every endeavour must be made to deceive the enemy as to the strength and dispositions of the troops in the defence, and as to the character of the defensive works. 6 CHAPTER I. — PRELIMINARY. (d) The defenders should be sheltered from the enemy's fire, and as far as possible screened from liis view, by natural or artificial cover, so arranged as to permit the greatest possible development of rifle fire. (e) The free movement of the attacking troops should be hindered by leaving or creating obstacles to detain them under fire or to break their order of attack. (/) The free movement of the defenders should be assisted by improving communications within their position, and clearing the way for counter attack. Shortly stated these principles in order of importance are : — (a) Choice of ground. (b) Clearance of foreground, (c) Concealment. {d) Provision of cover. (e) Creation of obstacles. (/) Improvement of communications. The above are dealt with in detail in subsequent chapters. 2. A thorough knowledge of the fire effect of all arms is necessary, in order to design good defence Avorks, Rifle fire, 3, Modern military rifles are sighted to about 2,800 yards. The slope of descent of the bullet varies from about -^^ at 1,000 yards to ^ at 2,800 yards. Height oi: The heights over which an average man can fire on level line of ground are : — ^^^' Lying down 1' 0'' Kneeling 3' 0^' Standing 4' 3'^ to 4' <6" These heights must be adjusted to suit different men ana varying inclinations of ground. CHAPTER I. — PRELIMINARY. 4. The following table gives the thickness in various materials- proof against modern rifle bullets at foint blank range : — Material. Thickness proof. Remarks. Clay 5 ft. Varies greatly. This is maxi- mum for greas7 clay. Earth, free from stones 3 ft. Ramming earth reduces its (unrammed) resisting power. Sand 2 ft. 6 ins. Rather more than enough. Very high velocity buUets have less penetration in sand at short than at medium ranges. Sand between boar Js IS ins. Brickwork . . . . . . 9 ins. If well built. Soft wood, e.g., fir, across 48 ins. 24 ins. proof at 500 yds. grain Hard wocd, e.g., oak, across 27 ins. 15 ins. proof at 500 yds. grain Wrought iron or mild steel Jin. Hardened steel plate iin. yV in. proof at 600 yds. Special hard steel .. 4 in. Shingle .. 6 ins. Coal 15 ins. Snow About 8 ft. 5. The usual projectiles for field artillery are shrapnel from Field field guns, and shrapnel and common shell filled with higr artillerj. explosive from field howitzers. Shrapnel can be used from field guns at ranges up to about 6,000 yards. The slope of descent of the projectiles of field guns varies from ^ at 1,500 yards to J at 4,000 yards, but howitzer projectiles have angles of descent up to \. 6. The penetration of shrapnel balls is considerablv less Penetra- than that of small-bore rifle bullets, but shrapnel with percussion tion of fuzes can be used with considerable effect against troops behind ^^^\1^^^.^' waUs. projectiles. Several foreign nations have introduced common shell filled with some high explosive for use with field guns. The special feature of such shell is that, on bursting, they break up into a s CHAPTER I. — PRELIMINARY. Field lio\\ il zerp. Heavy gnis. Modern aitilleiy. Ranges. very large number of fragments wHch are driven in all directions. They are not so effective as well burst shrapnel. 7. Field howitzers, firing common shell and shrapnel, have now been introduced into the service of most nations. They are light pieces of artillery, firing comparatively heavy shell, with low charges at high elevation, and in consequence possess gocd searching power* No practicable amount of extemporised cover, except as in Sec. 73, will keep out a howitzer common shell. The effect of the burst is very powerful, not merely from the fragments of the shell, but also from the blast and the fumes of the explosive ; but this effect is very local, and slight cover will suffice against the splinters. 80 Heavy guns up to 6-inch have been used in the field and will probably be met with in future. They are long- ranging, but their searching power is little greater than that of field guns. 9. The object of modern artillery is to reach the defenders of a parapet by means of fragments of projectiles burst in the right position, and not by breeching the parapet with the pro- jectile itself. An occasional sheU may strike and penetrate the parapet, but in the case of a shrapnel shell the damage to the parapet wiU be trifling, while in the case of a howitzer shell filled with high explosive, the effect will be no worse on a thin parapet than on a thick one. Thus it is useless to spend time and labour on making a thick parapet to keep out the actual shell. Against such fire, concealment is of greatest importance. Plate 1 gives some idea of the effect of bursting shells. 10. The following table (taken from " Combined Training," 1905) gives the various ranges of the different weapons : — Terms applied to ranges. Rifle. Field Artillery. Keavy Artillery. Distant Long Effective . . Decisive Yards. 2,800-2,000 2,000-1,400 1,400-eoo coo and under. Yards. 6,000-4,500 4,500-3,500 3,500-2,000 2,000 and under. Yards. 10,000-6,000 6,000-4,000 4,000-2,500 2,500 and under. riai^, /. Veiier&Sr^hflm. LJ* Li itio. London." Opposite pou^e S. CHAPTER I. — PRELIMINARY. 9 The extreme width of the area of ground struck by the bullets of an effective shrapnel is about 25 yards. The limit of the forward effect of shrapnel at effective range is about 300 yards. The radius of the explosion of a high explosive shell is about 25 yards. 11. The follo^ving terms are used with reference to artillery Matures and rifle fire :— of ^ire- High Angle Fire. — Fire from guns and howitzers at all angles of elevation exceeding 25°. Frontal Fire. — When the line of fire is perpendicular to the front of the target. Oblique Fire. — AVhen the line of fire is inclined to the front of the target. Enfilade Fire. — Fire which sweeps a line of troops or defences from a flank. Reverse Fire. — When the rear instead of the front of the target is fired at. 10 CHAPTER II.— FIELD GEOMETRY. 12. Before proceeding to the more technical portion of military engineering, it is as well to understand some of the simplest applications of geometry to the laying out of field defences. Slopes. Slopes are usually described by fractions, in which the numerator expresses the height, and the denominator the base of the slope. Thus, in Fig. 2, Pi. 2, the vertical height, B C, is jr of the horizontal distance, A B. The slope A C would, therefore, be called a slope of ^ (verbally, one in six). In Fig. 1, the vertical height B C is four times as great as the horizontal distance A B. The slope A C is called -i (verbally, four in one, or four over one). Slopes are sometimes expressed in degrees. A good rough rule for converting degrees of slopes into fractions, or the reverse, is to divide 60 by the number of degrees expressing the slope, the result gives the denominator of the fraction whose numerator is 1, e.g., 5^ slope = ^i^"' ^^ 1 ^^ ^- slope. N.B. — This formula should not be used for slopes steeper than 30^ To lay out 13. To lay out a right angle. Let X be a point in a given a right straight line A B (Fig. 3), from which it is required to set oS a *"gl^- right angle. Take any point C in A B, and drive in pickets at C and X. Take any convenient length of tape C D X, and make loops at either end, and find its centre D by doubling it. Xow place the two loops over C and X and stretch the tape taut into the position C D X. Take D X off the picket at X and turn it round till it comes into the position D E, in prolongation of C D. Join E X, which gives the right angle required. 2nd Method. — From X measure off a distance of 4 units X C along A B (Fig. 4). Take a piece of line or tape 8 units long, and apply one end to the point X, and the other to the point C ; find a point in the tape 3 units from X, and seizing it at this point, draw the bight out to D, till the line is taught, then C X D is a right angle. This method is founded on the I^lajt€> Z, Fi^.1.^ c Field Geometry . A C J^ff.5.[ ^x ^^ ^ c :b -'C SB ■. b >> >> Tools. i _S £ 3 1 £, ^3 3 3 i. >> < .^^ - ,, — , , -- PROFILING ^r^.^, Jhter^ior- csrss ''////w//////w/Mmmm^, s/ae .s OS. Wfiier&Grahan.L'* UrhoLoodon Opposite pa^ tS. CHAPTER IV. — WORKING PARTIES, ETC. 15 23. Tracing a work consists in laying out so much of its plan Tracing, on the ground as is necessary to guide the distribution of the working parties. This may be done by a mark on the ground, or by tapes. In hasty defence work tracing with a tape is usually only necessary for night work. 24. When making works of high command, profiles should be Profiling, put up to guide the construction of the parapet. {See PI. 5.) For high profiles it is best to drive stout pickets into the ground at the position of the verticals, construct the profile bodily to a straight line, lying flat on the ground, and then up-end it, and nail it to the pickets on a level line. Profiles are laid out at right angles to the crest line. They should be placed at intervals of about 30 feet, two at least being required for each face near the angles. High profiles should be secured by stays or light guys, or they are liable to be blown down. 25. For all intrenchments the normal distance apart at Orgauisa. which the men are spaced for work is two paces (5 feet). ^^^^ 9^ This can be reduced, if necessary, to 4 feet, but it cramps the "^*^ff^"S diggers. Task work is better than working for a fixed time. In arranging tasks it is better to under estimate the men's powers in order to avoid incomplete tasks. In arranging reliefs, the following rules should, if possible, be adhered to : — (1) The second and succeeding reliefs should have less earth to excavate than the first, as the diggers have further to throw. (2) If fossible, each relief should leave a vertical face of earth for the next relief to commence upon. For instance, in PL 5, Fig. 1, the dividing line between the reliefs is vertical and not horizontal. 26. _A party of the necessary strength for the work in hand. Detailing including a reserve of one-tenth, having been demanded, working should be detailed from a company, battalion, brigade, or P^^'^^^s. division, and not formed of detachments from difierent com- panies and corps. 16 CHAPTER IV. — V/ORKING PARTIES, ETC. The party is then marched to the tool depot to get their tools, which should be ready laid out, according to the detail of the several parties, either in rows or in heaps, the men in the former case filing on the rows and taking up a pick in the left hand and a shovel in the right, or filing between the heaps and receiving the tools in the same order in passing. For extending men for work, see " Infantrv Trainiog,'* 1905, p. 96. If the party be large and the work of a complicated nature, such as a redoubt, the men should be divided into detachments, each under a superintendent, corresponding to definite portions of the work, formed in column at some distance from the site, and successively extended along the line, driving in their picks on the left of their tasks, and laying down their shovels along the front. It is sometimes advisable, in order to save time in extending, to keep a separate detachment for distributing on the excavations at the angles. No work must be commenced till the distribution of the whole is complete, as it is difficult to remedy mistakes when work has once begun, the subsequent shifting of men invariably tending to confusion and possibly loss of tools, clothing and accoutre- ments. Double When the men available greatly exceed the tools in number, manning i^, j^^y be advisable to tell off tw^o men to each set of tools, and *° so complete the work in about two-thirds of the ordinary time. Superintendents should be relieved at alternate hours to the working parties, to ensure continuity in work. When the distance that the earth has to be thrown is too great for the diggers to deposit it in its final position in one throw, shovellers wiU be necessary as well as diggers. Methods 27. Diggers should commence on the left of their tasks, in of execu- order to incommode each other as little as possible. tmg tasks. j^ excavating V-shaped ditches the slopes should not be formed until the last relief, rectangular portions being taken out first. If not under fire the earth first excavated should be furthest thrown. CHAPTER V. — MATERIALS. 17 In making fire-trenches the men should try to get cover as soon as possible. Sods and lumps of earth should be used for revetting the interior slope, which must be made as nearly vertical as possible, the revetting being carried on with the parapet. CHAPTER v.— MATERIALS. For approximate time required for carrying out work referred to in this chapter, with labour and tools, see table, p. 120. 28. The materials, which are mostly available for the con- Earth, struction of field defences are earth, st-- nes, timber and brushwood, while railway plant, iron sheeting, wire barbed and plain, &c., may often be obtained. Of these materials earth is the most valuable as well as the most generally used. For the purpose of field fortification, earth is usually pro- cured from the trenches dug as near as possible to the place where it is to be used. The steepest slopes at which thrown-up earth will stand is about 45° or \. 29. Sods are used for revetments and also to form walls in Sods, special cases. They should, if possible, be cut from meadows growing thick grass. Each sod should be about 18 inches long, 9 inches broad (these dimensions depending, however, on the width of the spade) and 4| inches thick. 30. Stones may be employed to form rough walls in places stones. where digging is difficult or impossible. A well-built rubble wall, 12 to 18 inches thick, will keep out bullets, this thickness being necessary to avoid having any " through " joints. Two such walls about 10 feet apart afford good protection against artillery fire, the outer wall, which should be at least 2 feet thick, serving to burst the shell. 31. Timber is used in the construction of bridges, huts, Timber, splinter-proofs, stockades, abatis, &c. (5289) B 18 CHAPTER V. — MATERIALS. Felling 32. The tools employed for felling timber are the felling axe, Timber. ^|^g hand axe, the cross-cut saw and the Jiand saw (PI. 4). Of these the felling axe in the hands of an experienced work- man is, probably, the best of all. The hand axe is only suitable for felling small trees not exceeding 12 inches to 15 inches in diameter, but it may be employed with advan- tage when men practised in the use of the felling axe are not available, as it requires little or no skill in handling. The cross-cut saw or the hand savr may also be used, the latter with small trees only, provided that measures are taken, by wedging or otherwise, to prevent the weight of the tree from jamming. Inexperienced men can use the cross-cut saw more easily and safely than the axe, and can cut more quickly with it. When convenient, it is best to fell a tree in the direction of its natural inclination. In using the felling axe, the tree should be first attacked on the side on which it is required to fall, a rope being employed, if necessar)-, to pull it over, as, for instance, when the natural inclination is not in the required direction. When the tree has been cut into as far as the centre, or a little beyond it, the workman should change over to the opposite side and commence cutting about 4 or 5 inches above the former cut until the tree falls. The cuts should be as shown in Fig. 4, PL 4, where the arrow indicates the direction in which the tree is required to fall. With beginners, or when it is not important to save timber, and when there is no objection to leaving the cover which high stumps afford, the point a should be the height of the hip, h c should be about three-fourths the diameter of the tree. It may sometimes be convenient to employ both the saw and the axe to cut down a tree. In such cases the axe should be used on the side towards which the tree is to fall, and the saw en the opposite side. The teeth of all saws used for cutting down timber should be set wide. Cutting 33. Brushwood is much used in military engineering for !!L"!^" roadmaking and revetting purposes, and for the construction of gabions, fascines, hurdles, &c. WiUow, birch, ash, Spanish chestnut and hazel are the most suitable kinds, and work best if cut w^hen the leaf is off. ood. Thff^' G. V Tiq.Z or'JBnttorL Bru shwood. JifeZfvoOi of 7>iftdz7i^^r*itsJuvood ^zy.;. /rj) JJVB ^^.5 4^06 S. 05 .eilerSrGraham. L'* Lirho, London Opposite pajge J 9 CHAPTER V. — MATERIALS. ID As a rough rule it may be taken that 1,000 square yards of brushwood, years old, make up three G.S. wagon loads. 34. Withes, for binding purposes, in lieu of wire spun yarn, Withes. &c., are made of pliable wood, such as willow and hazel. They should be 6 feet to 7 feet long, | inch in diameter, and made pliable by being well twisted, the thin end being placed under the left foot, and the rod twisted with the hands, avoiding kinks. If the rod is stiff a smaU. piece of stick, lashed across the butt, will be of use in twisting it (PL 6). 35. A fascine is a long faggot tightly packed and carefully Fascines, bound, used in revetments, for foundations of roads in marshy sites, and for many other purposes. The usual dimensions are 18 feet long and 9 inches in diameter. It is made in a cradle of trestles placed at a uniform level (PL 7, Figs. 6 and 9). The brushwood, trimmed if possible, is laid in the cradle, projecting about 1 foot 6 inches beyond the outside trestles, and adjusted so that there may be no weak place. Crooked rods must be half sawn through and straightened. The fascine is then gauged with the choker (Fig. 7), Choker, which consists of two wooden levers, 4 feet long, connected at 18 inches from their ends by a chain 4 feet long, provided with two gauge rings, 28 inches apart, corresponding to the circumference of the fascine. To use it, two men, standing one on each side, place the centre of the chain under the fascine with the short ends of the levers uppermost, cross the levers to each other over the fascine with the short ends down, and bear down on the long ends until the gauge rings meet. Binding must be commenced at one end. The first binding Binding, (of we, spun yarn hoops or withes) is put on 3 inches beyond the outside trestle, and the remainder (12 in all) at intervals of about 18 inches. This admits of the fascine being cut, if required, into 9 feet or 6 feet lengths. The ends of the fascine are sawn off 9 inches beyond the outside bindings. In all cases the fascine must be choked close up to the position of the binding while the latter is being put on. With withes an eye is formed at the tip, the withe put on With under the fascine, the ends brought up, the butt passed through withes. the eye, turned back and twisted round itself (Fig. 5). (5289) -B 2 Piclvets. Gabions. Brush- wood gabion. 20 CHAPTER V. — MATERIALS. Length. Diameter. feet ins. ins. ins. 3 6 ftol 2 6 li » li 6 6 3 „ 4 3 6 1 „ 2 1 6 1 „ U 5 li „ 2*' 2 6 1 „ li 1 6 h „ 1 With spun yarn the centre is found and laid on the fascln^ and the yarn is then passed twice round the fascine, haule taut, and fastened off with a reef knot. Both withes and yarn are apt to perish. Wire is laid on like the yarn, passed twice round, haule taut, the ends t\^asted together and tucked in ; 14 gaug is a convenient size. A piece of hoop iron may be used for binding. It should b 31 inches long, with notches cut at opposite vsides, and 2. inches apart. The iron is passed round the fascine, and th notches hitched together (Fig. 8). 36. Pickets are made from brushwood for various purposes The following dimensions are useful for reference : — For gabions fascines fascine cradles hurdles tracing high wire entanglement low wire entanglement sodwork 37. Gabions are cylinders open at both ends, which, when standing on one end and filled with earth, make a strong revetment. For dimensions see PL 8. They may be made of almost any material capable of beina bent or woven into a cylindrical form, such as brushwood,^ canvas, sheet iron, ware netting, &c. Their employment in the future is likely to be more limited than in the past, as revetments are as a rule lower, and so simpler forms of support will suffice. 38. To make a brushwood gabion, a circle of 10| inches radius is traced on level ground, and an even number of pickets, usually 10 or 12, driven at equal intervals round the inside of the circumference {see Fig. 1). The pickets are 3 feet 6 inches high, | inch to 1 inch in diameter, and must be driven with the thick and thin end alternately downwards. PlaJte 7 Brushwood. Fascines :Fiff.7. ^a^'czne. Choicer^, M-PO->^. \ ^ ' . >,< s^,mf4,.^ ,..> .. .o WelleriGrahsff'. L" Lirtxi Lerdw Oppas/Lte pcx^e 20. i Plnte 8 Brusjiwood. Gabions . S&i/ym' yj'ithj \vir& or' spuny i/oc/yz/ Tiff. /. Tzff.Z. Tiff. 4^. jyl || HI HI i [H 1 'H3 i Ti.j.5. Tig. 6. Tz^.S J^-9 ^....2f)"--> Weo Lordon Oppoicte page SO, en AFTER IX. — EARTHWORKS. 31 CHAPTER IX.— EARTHWORKS. 64. Earthworks may be classed generally under two heads, Earth- viz. : — Trenches and Redoubts. works. The defences of an extended position will usually be trenches. Trenches. They may be disposed in irregular lines arranged mainly for frontal fire, as may be best suited to the ground, or in groups with intervals. The ground sometimes permits of these groups being arranged so as to provide flanking fire for the intervals and front of other groups. In laying out such trenches the danger of enfilade fire must be considered. Redoubts will be used principally for isolated positions, Redoubts, such as posts on lines of communication, or a chain of advanced posts watching a long line of front. When placed as supports to the front hne of an extended position they must be care- fully withdrawn or concealed from view. With all intrenchments invisibility is of the utmost impor- Inrisi- tance, and is almost of as much value as the cover itself. bility. 65. Every effort should be made to utihse and improve Existing existing cover in order to save labour and time. On the ^o^^^'- defensive there will generally be time to make a trench before the attack commences. In attacking across open ground, under fire, men will not, as a rule, be able to stand up and dig. Attack. When brought to a halt, they will have to make such cover as they can while lying down, but no opportunity should be lost of entrenching ground that has been gained. Siting of Trenches — {See also " Combined Training," 1905, Section 126). 66. The following points must be considered : — Siting of A good field of fire ; this is most important and should trenches. not be sacrificed to any other consideration. As much concealment as possible, particularly from the enemy's artillery. Ground in rear suitable for reserves. When the position includes commanding ground the firing hne need not necessarily be on it; it should be 32 CHAPTER IX. — EARTHWORKS. Arrangfe- ment of trenches. in the best position for fire effect. It will often be a good plan to place the firing line at or near the foot of a slope, so as to obtain a grazing fire, with the artillery on the high ground above. The advantage of high ground for a defeusive position is often over-estimated. It need oidy be high enough to conceal and shelter the defenders' reserves and their movements, and to expose the movements of the enemy. 67. The arrangement of trenches should be simple. There should be one main line of defence. Several tiers of trenches may sometimes be useful, to increase the volume of defenders' fire, and also to deceive the attack as to the actual position of the defence ; but there should be no idea of using these trenches as successive lines of defence. The defenders should understand clearly which is the main line of defence, and what it is that they must hold on to when the assault is pushed home. The main line should not as a rule be continuous. If echelonned in suitable lengths, say for companies, or even smaller units, it will be more difficult for the enemy's artillery to get the range. In tracing a trench attention should be paid to probable enfilade fire. Every artifice should be used to mislead the enemy as to the positions of the trenches, e.g., conspicuous dummy trenches to draw his fire. Invisibility. Tnvisi- 68. Every effort should be made to conceal the trench. biiity. Concealment may be gained by (a) careful siting, i.e., position, (h) Assimilation to surrounding ground. When possible a position should be studied both before and after the construction of trenches from the front, and especially from the enemy's artillery positions. Well-marked features of the ground, such as isolated hedge-rows, Hues of road, sharp changes of gradient, or anything which casts a shadow are, at long ranges, more visible than the trenches themselves. The neighbourhood of such objects forms a target, especially for artillery fiie, and should when possible be avoided. PlrrJe JO Fire Trench es Surplus ea7*th. m/iy he hecuped- or sprecLeL in. re^xr of trerhcJv *806-S as we'-e'SiGra^aT' L'' iJtio Lonoon Opposite pajqie.33. CHAPTER IX. — EARTHWORKS. 33 The front of the parapet maybe covered with sods or branches, or whatever will make them look like the surrounding ground. Sharp hues must be avoided and attention must be paid to back ground. If the parapet is on the skyline, spare earth may be piled up behind the trench to make a back ground for the defenders' heads. As a rule, however, a sky line is to be avoided. The parapet should be kept as low as possible consistent with fire effect ; in some cases no parapet is required. Trenches. 69 . Trenches are distinguished as "fire trenches" and "cover Trenches, trenches," according as they are for the firing line or merely to cover troops not actually engaged. Fire Trenches. 70. The design of the trench will depend on the time and Fire labour available, on the soil and on the siting, but the following trendies, points are important : — (1) The parapet should be bullet proof at the top; 2 feet 6 inches to 3 feet will iLsually suffice. But see Sec. i. (2) The trench should be as invisible as possible. (3) The interior slope should be as steep as possible. (4) The bottom of the trench (unless there is a step) should be wide enough to allow men to sit in it. (5) The interior should be protected, as far as possible, against oblique and enfilade fire, and sometimes from reverse fire, (G) Drainage should be attended to. 71. Types of fire trench are given in Pis. 16 and 17, but see Sec. .3. Fig. 1 gives good cover against frontal artillery fire, and allows room for the supernumerary rank to pass behind the firing line. To excavate the normal length of 2 paces of this trench will take an untrained man about H hours, in moderately easy ground. (528'J) c 34 CHAPTER IX. — EARTHWORKS. In Rpecially difficult soil the width may be reduced to 2 feet. Should time be available, the cover and the facility of com- munication may be much improved by deepening and widening the trench, as shown on PI. 16, Fig. 2. Should a higher command than 1 foot 6 inches be required, to enable the defenders to see the ground in front, the parapet must be heightened with earth obtained from widening and deepening the trench. A firing step, at least IJ feet wide, is necessary 4J feet below the top of the parapet, the interior slope of which must be revetted. PI. 16, Fig. 3, is a case where the ground in front can be seen without any command, and it is desired to dispense with a parapet for the sake of concealment. The excavated earth must be scattered or removed to form a dummy parapet. PI. 44 shows how fairly good cover can be rapidly obtained for men lying down ; the trenches can be connected up £is shown by the dotted lines. An elbow rest is & useful feature in a parapet. It increases cover considerably, gives support to the men while firing, and is convenient for ammunition. It should be 9 inches below the crest and 18 inches wide. Earth thrown up should not le rammed. Head Cover and Loopholes. Head 72. Head cover tends to diminish the number of rifles that cover. p^j-^ i^g p^^ jj^ ii^Q ajj(j reduce the field of view and fire, and generally makes the work more conspicuous, but is of undoubted advantage for protection, especially against shrapnel. It requires careful arrangement so as to ensure the maxi- mum of fire effect and of invisibility with the minimum of exposure. It will usually be obtained by making notches in the parapet for the rifle, or by loopholes. Lo'^p- Loopholes can be made of sandbags, sods, or other materials hole^. available on the spot, such as biscuit boxes or sacks filled with R^Ltt J 7 2 .^ O -1 ^ O o ^^ w ^ ^ > "?3 o w -I < C; u 0! 1 I z h '^ ^ to q: .^ I o ^ 7 CO S o h -|W t^ "^ lli Q < 1,1 'C q: EC ii Q — o u. D ^ cr o o <0 UJ 'O to y a: LI 53 > ^ < a: h W€Uftr*6rahani. \J.* Lirtio.London. Opposile pCLg& J^4. PZccLe JS. Head Cover . S ojixL'bcuf Loophjole with. Loophole Plcut es on Lei^el^ groujv cL. Ftg. 1 Fig. Z Section Fi€f. 3 S andbag Loophol e Sod Plan of j*ir Courses Plan of^&tt Courses Stbdks to cccrry tap soTLdba^s S ECTION ler&Graham.L" Urho, London Opprtsitje jtctgfi>3S. CHAPTER IX.~ EARTHWORKS^ 35 earth. The size of the openings must be governed by the ground to be covered by fire,* and can best be regulated by testing with a rifle with the bolt removed to ensure that neither line of sight nor line of fire are obstructed. Sandbag loopholes, as shown in PI. 18, Figs. 3 and 4, can be Sandbag made in a continuous line as close as 3 feet 3 inches from loophole, centre to centre. Sandbags sag a good deal unless well supported. Loopholes made with earth or sandbags may have the larger opening either inside or outside. If the larger opening be inside, the loophole is very much less conspicuous, which is often a point of great importance. If the larger opening be outside, a defender can fire with much greater ease, since he can cover the whole arc without moving his position. The choice must depend upon the requirements of the place. A compromise between the two above methods is shown in , PI. 19, Fig. 1. A very good form of loophole which has the advantage of Con- giving a wide field of view, is a slit all round the work, tinnous continuous, except for the supports of the material above {see ^^^ ^^ ^' PL 25). Loopholes made with hard material, such as stone, must have the larger opening inside to prevent ricochet. Steel loophole plates, see Figs. 1 and 2, PI. 18, are articles of Steel store. They make the best head cover, but cannot, as a rule, loophole be provided for hasty defence work. plates. Loopholes should never show against the skyline, but should be blinded, say, by canvas hung behind them. The front of the loophole may be masked with branches, long grass, fee. Overhead Cover. 73. Overhead cover gives the best protection against shrapnel from guns and howitzers. It is especially useful * The minhiium depth of openings for a parapet 2 feet 6 inches tliick on level ground, using the new service rirte at 2,000 yards range, is, for the inside, six inches ; for the outside, four inches. (5289) c 2 3G CHAPTER IX,— EARTHWORKS. against oblique fire ; 9 to 12 inches of earth, or say 3 inches of shingle, supported by brushwood or other suitable material, will suffice. (PI. 20.) Two sheets of corrugated iron sloping to the rear at about |, afford good protection against shrapnel {see PL 19.) The corrugations must be parallel to the line of fire. Overhead cover of above natures will not keep out a common shell, but the effect of a burst in the trench can be locahsed {see below). A row of heavy steel rails arranged in the same way as the corrugated iron, has been found to be practically proof against G-inch howitzer shells filled with high explosive. Overhead cover against weather may be made with branches, corrugated iron, canvas, or any other covering available. See also Sec. 88. Traverses. Traverses. 74. Open trenches and parapets which may be exposed to enfilade fire and to the oblique fire of artillery, should be traversed and recessed. Traverses are simple means of gaining protection against enfilading shell, and also of localis- ing the effect of a shell bursting in the trench. They are also effective against rifle bullets, on account of their flat trajectory. An irregular fine of trench will answer the same purpose, when it suits the ground. Against shrapnel bullets coming obliquely, or in enfilade, traverses will not suffice, on account of the steep angle of descent of the bullets. Eecesses made in the parapet, lar^e enough to hold one or two men, give the best protection against these. See PL 21. Such recesses are best made after the trench is excavated. 75. Traverses to localise bursts may consist of two walls of brushwood, with about 1 foot of earth between. Protected Look-out. Look-out. 76. In all trenches some sort of protected look-out is useful. It should not be distinguishable from the front. A well-made loophole may suffice for this purpose. Flate. J9. Fi^.1. Sod Loophole J^.2 Elbow ^es\ SocLs Sods Overhead Cover -K / 6 Welter & Graham. L^f Litho London. PUlIa 20 \, TTmni ■3. I UJ < (0 1 ?■ »- > <0 ^ Q < ^ -^ Z UJ ^ co^ < n z .^r U4 J? -^ J (0 - "S oc oe S S 3C 3 s *, u UJ J-^ z QC UJ UJ ^ a: ? H P ? 111 ^ 0^1 v^ Plat^ 2 J. ^fic^ e "9 TofoULowpUjute20 PLote 22 Gun Epaulment. Fr^l \ 7'.^" . ^ SecwoTL on, A .a . » V* ~^-/2«ORy-$" for cortt&vt^ o^ ^er/n near) /OO F^ — irt GUN PIT '%1li]!iLli% ^ ^ -30 97 34- 91 88 '^ k: /O' ^ rear crest of hill COVER FOR ^ WAGONS. ^ <.. Section on AB -/-/•6 Section S/tfe- • r.. we;!ers.r-a-3r To follon' plate 22. chaftrr ix.— earthworks. ^ 37 Drainage of Trenches. 77. This is an important point, and should be attended r)rainage. to from the outset. A gutter should be formed in the trench, usually at the back, and the bottom of the trench sloped to it. Any water collecting in it should, where possible, be led off to lower ground, otherwise into soak pits, which may be about 2 feet or 3 feet in diameter and 3 feet deep. Communication Trenches. 78. If time admits covered communications should be Communi- arranfTed behind the firine line. These, while concealing the cation movements of the defenders, will also permit of the firing line being withdrawn altogether while the artillery bombardment is going on. A trench similar to PI. 16, Fig. 4, will usually suffice. It may be necessary to make long lines of such approaches, but every possible use should be made of the ground to mini- mise labour on them. They may require parapets on both sides, and where much exposed may be given overhead cover. Cover Trenches. 79. Cover trenches {see PI. 24, Fig. 1) are useful to protect the Cover firing line during a bombardment, and for troops not actually trenches, engaged. The section of these trenches may be as in that figure, or, if more time and material be available, as in Pis. 28 and 29. When time is limited and materials are not at hand, a section similar to PI. 16, Fig. 1, might be employed, but with slightly higher parapet and no elbow rest. Cover for Artillery. 80. Cover for field guns will take the form of epaulments, or Cover pits, as shown in Pis. 22 and 23. An ammunition recess must for be provided close to the gun, and cover for one or more ammu- ^^'"^^^7- nition wagons near the emplacement is also desirable. There should be covered communication between the gun emplace- ment and the wagons. Parapets to be bullet and sphnter 38 CHAPTER IX.— EARTHWORKS. proof. The height of the parapet should be regulated by the site and range. Three feet is suitable for medium and long ranges. Howitzers will, as a rule, be in concealed positions, wdierc they can only be reached by high angle fire. If they are likely to be for some time in one position, e.g., in siege operations, they can be surrounded by splinter-proof walls [see Traverses). Field redoubts. Definition. Kmploj- ment. Detached posts. Trace. Field Redoubts. 81. Field redoubts are Avorks entirely enclosed by defensible parapets. Their dimensions should, as a rule, be such that they could be constructed in from 12 hours to 24 hours. It may be generally laid dowm that redoubts in defensive positions must not, under ordinary conditions, be used on sites w^here they can be recognised as redoubts by the enemy: This \\\\\, as a rule, prevent their employment in the front line, although irregularities of the ground, &c., may shelter certain portions of this line where redoubts may find place. A redoubt has greater resisting power against infantry than a group ol trenches. As supporting points in rear of the front hne, redoubts w^ill more often be employed. In such retired positions there will generally be sites which, while commanding the foreground, will not be exposed to view from a distance. It should be remembered that a redoubt does not necessarily need a high or thick parapet ; a fire trench parapet may suffice. 82. Redoubts may have to be used for detached posts, and posts in lines of communication. Such works wall often have to be a refuge, shelter and depot for passing troops, and room inside must be given. It will hardly be possible to make these works invisible, as it is essential that the parapets should conceal the interior from view\ Plenty of splinter-proof cover should be provided, and a good obstacle near the parapet is essential. 83. The plan or trace of a redoubt will depend on — (a) Fire effect required from it. (6) Configuration of the ground, (c) Proposed garrison. Plate Z^. C over Trenches Fig r REDOUBT( Low Command) 111 . Gerve^aL JPZccn^ JE^,Z^ JUL -K --- . WIL "IVTi^N. lOrrven^ X 10. me^ -<''XA'\ JPlany of^Shelter'S. 430S.B OS. Welleri Graham. L'^ Irrtio.LonJorv, Opposite pa^e>39 FJjubt 25. ■ — I < > o UJ o °-5 O 111 u H g ,6 Ul <0 (/) O UJ (/> «* ;^ z o 0^ - _i o ^ ^ ^ o o o > 08 >- l> = ? UJ ^ ° J i y H > Z 10 < UJ < si 2 o O I -> 10 WtllerfcGrdhdni. L'^ Lirho.London Opposite pajCfB' 40 WeilertGraham L'.' Litho, London To folZow plaJ^. Z6. /^lal^ 2S WellerlGrsham f* Urho.Looden Vlat^ 29 HASTY R EDOU BT BLINDAGE IN REAR OF FIRE TRENCH SectCoTh t/iro ' ^iCrtjcLcyfe^ . Weiler* Graham. L"" LiLho London To fcUow plodbe 28 CHAPTER X. — OBSTACLES. 41 92. Obstacles should always be provided in connection Obstacles, with redoubts. They must not mark the j^osition of the redoubts. The nearer the obstacle is to the parapet the less labour and material will be required, and the more efiective will be the defence, especially at night. CHAPTER X.— OBSTACLES. For time, labour, tools aiid material required, see table, p. 120. 93. Obstacles judiciously placed add very much to the strength General of a defensive position, and are especially useful as a protection eonditious against night attacks. The following conditions should be observed : — (a) They should be under the close rifle fire of the defender. For small posts or redoubts they should be quite close, so that they may be effectively defended at night. They should afford the enemy no cover, and, if possible, be sheltered from his artillery fire. (b) They should be difficult to remove or surmount, and will be most effective if special appliances, not usually carried by troops, are required for their removal. (c) They should, if possible, be so placed that their exact position may be unknown to the attacking force. (d) Except where the purely defensive is inevitable, they should be arranged so as not to impede counter attacks. (e) As obstacles on a large scale may interfere with an Caution. advance, they should not be constructed without authority. For the protection of small posts at night some sort of automatic alarm is desirable, such as tins hung on a wire, rifles fired by trip wire, &c., see p. 47. 42 CHAPTER X. — OBSTACLES. abatis. 94. Abatis formed of limbs of trees firmly picketed down and interlaced, with the branches turned towards the enemy and pointed, form a very efficient obstacle (PI. 30). Figs. 1 and 2 show method of covering abatis from artillery fire. Fig. 3. — The method of forming an abatis from small branches. Several rows are used, the excavated earth being replaced after the branches are secured. To make abatis carefully, at least a relief of six hours and a strong working party are required, so that very little of it can be undertaken in hastily-fortified positions. A very effective abatis may, how- ever, be made much more rapidly when the trees can be utilised where they are felled, no excavation being made for them and the branches being only roughly trimmed. Strands of wire interlaced between the branches are a useful adjunct to abatis. Tree 95. Tree entanglements (Fig. 4, PI. 30) are formed by cutting entangle- trees, brushwood, &c., nearly through at a height of about 3 feet, and interlacing or securing the branches by pickets to the ground. They make a formidable obstacle at the edges of woods and orchards, and for blocking roads, and can often be formed w^hilst clearing the foreground. Wire 96. A low wire entanglement is formed by stout stakes entangle- (Jnyen into the ground about 6 feet apart, in rows arranged Low ^' chequerwise, their heads being connected by strong w^ires twisted round them and crossing diagonally about 1 foot or 18 inches above the ground (Fig. 3, PL 31). The outside pickets should have ware stays, as shown in Fig. 3. It is not a good obstacle unless constructed amongst brush- wood, small bushes, or long grass, which conceal it, when it may be of great use against mounted troops. It is especially effective in the bed of a river. High. 97. High wire entanglements form effective obstacles, es- pecially if barbed wire be used. PI. 31, Figs. 1 and 4, give two different types. Fig. 4 shows a method of improving a wire fence, but is not so efficient an obstacle as that shown in ments. I^lcutG 30. Obstacles Abatis. j^ 1 Palisades Fi^.5 4< N A 1 K I l' ' ' 'i iil 'I] I " 111 '; "I |I|iil '-11 'I' ' I 1 I FlxuL of PcLbuscule »60B3O5. Welter & Graham. L^ LithaLowJon. Opposite p^e. 4Z. Pictte^Sl. F^,1. Obstacles . High wire Entanqlement Dixfj^onxxX -yytres .. I'LuU 34. Defensible POST. Burma _K^ r. /. Fig, 2^. m^- JFl^.S Profile of Stockade k 3a/776>oo 'SfocAa<^e. Strong bamboo j^ ^7>t^^„ „ ' to around. WederiGraham. 'J* LiHiotondon To f'oVifrw jjlxxte^ 33, I'Ujt, :i5 Defensible Post . LusHAi 1889 . (For section across Stockade ^ see P/ate ^Z.) 7'o foUjn^' pljoJj^J^} pixxju. se welier 6. Graham. Lf^ brt>o,Loix»«fl To follow pCaJ^35. PUitsSl, in O X o o _» CCS Q^l 51 a: 'I °=! o z It ^ ^^ Ill or ■S i ^ < o h- "^ ^ a Hi> z ;i3? 3 O ^r|-^ o UH R t ^ "^ a: vN«. ^^ - a l..1 .3^ '^ i it ■ '-; *S»S.ti.ts. WtllerSi Graham. Lr^ Limo.Ujndon. To folloyv pla.tR 36 «i 1 MxxtBJS SECTION A.B TtoeToTSW. Weller&Graham L"^ L 61 JPlxjte 39 WelleriGraham ' *.* Li»t\o.London To foiLo^y pUf^ 38. Flrrfe ^0 VVcller* Graham. Ltd Litho.London Tlate 4i. 7b foOoM pl^xte. 4€. *? Flrite^ 42 Fixed Rifle Batteries. /%./ z. s Caracas 16 -vvvd^t- Z'A' 7 slot '3 lrj7i^ T^fi/Jv strv n^a 3 ^ 1 /z i.... 4 •6"" ^curthi\ r-*-».,»,^ Fvg.2 . Elevation . ^ y[J.j>l'?ie z -^"^ z:_ ,yL ....>. ,f ^X B ^, eloTTfip ! S'V/z 430& :e Wellerjr Graham, L?^ Litho. London, h^lcLie, foVUm- CHAPTER XI. — DEFENCE OF POSTS, VILLAGES, ETC. 47 suit our weapons, and executed with the aid of good tools and engineering skill, will, as a rule, be suitable for our own use. For types of such defence, see Pis. 32 to 41. 111. Automatic alarms and flare lights, worked mechanically Alarms or by electricity, are useful where night attacks may be ex- *^^ flares, pected. They are usually combined with obstacles. One of the simplest alarms is a row of tin pots, each containing a pebble, hung on a wire fence so as to rattle when the latter is disturbed. A piece of tin, 2 inches to 3 inches in diameter, e.g., the top of a tin pot, bent round the wires answers the same purpose. Trip wires can be arranged to fire a rifle or to fire a cartridge, which in its turn will ignite a flare {see PI. 43). For electric alarms, see Part 1, 1.M.E. Arrangements for automatic alarm signals in connection with entanglements or intermediate fences, generally have to be improvised on the spot with whatever material is available. 112. The spring gun shown in sketch (PI. 37) is simple to fix Meclmni- and is reliable in its action ; another mechanical device is cal alarms, shown in PI. 43. 113. Means of temporarily illuminating the foreground will lHumiua- suggest themselves according to the material available. The ^^^" ^^ illumination must be arranged so as to leave the defenders in ground, shadow. A "flare " made of tow and oil is described on PL 43. A special illuminant is made in the Ordnance Factories under the name of " Lights, illuminating, wreck." This can be lit with a match or with either instantaneous, or safety fuze. The instantaneous fuze should be stripped to ensure good contact. The light will illuminate a circle up to about 100 yards diameter and will burn for 20 minutes. 114. On a dark night it is difficult to ensure the men's rifles Fixed rifle being aimed in the required direction. Any device to assist i*«st. them in this matter is useful. In the South African war of 1899-1902 " fixed rifle rests " were employed to fire along the obstacle. By the arrangement shown in PI. 42, a number of rifles can be clamped in the required direction and elevation, while only one man, who can be practically under cover, is required to load them; failing this, some such device as a wooden bar can be arranged across the loopholes, to prevent 48 CHAPTER XL— DEFENCE OF POSTS, VILLAGES, ETC. a man raising his rifle barrel too high. Posts painted white on the defenders' side make a good aiming mark, if the night is not too dark. Steel loop- 115. Loopholes made of sandbags, sods, &c., unless very- holes, carefully made, do not afford a good field of view and fire combined with adequate protection. To meet this objection a steel loophole plate has been introduced into the service. It would be specially useful for det?vched posts. {See PI. 18, Fips. 1 and 2.) Entrances. H g. The entrances to closed works must be carefully attended to. They may be closed by a gate, barbed wire or other obstacle. When wire is used, a good plan is to construct an intricate winding approach, making access by night difficult. In all cases entrances must be covered by the fire of the defence. Entrances to admit artillery require a width of 7 feet. Defence of Villages. Tillages. 117, Villages will very often occur in or near a defensive position, and although they are unsatisfactory for defence they must generally be occupied, rather than be left to the enemy. They conceal the disposition and strength of their garrisons, and afford a shelter from the weather, but they take up a large number of men who are necessarily scattered. A village should be divided up into well defined sections, each held by a tactical unit. Each section might have two lines of defence. There will be a general reserve for the whole under the commander of the village, to reinforce a hard pressed section, make local counter attacks, and furnish the garrison of the central keep of the village, if any. 1 18. The arrangements of the defence might therefore be as follows : — (1) Clearing field of fire. (2) Making communications. (3) Providing or improving cover for first line along hedges, garden walls, &c., loopholing walls of houses as a second line. (4) Placing obstacles. This would be partly done at the same time as (1). i(5) Preparing keeps. I Plcite ^74. Cove^ for* Oiztposte Fia 3 Trvo/er^G Cfyvermg entrccnco flpow^ exposed iScceJ COVER - LYING DOWN 5 0- -><■ s- o' ^> ^^w v^;# %^?i^ > CHAPTER XI. — DEFENCE OF POSTS, VILLAGES, ETC. 49 Defence of Camps. 119. When operating against an enemy who is accustomed Camps. to make night attacks, the defence of camps is a most important question. There are two essentials for camp defence : the first is a well defined firing hne for the defenders, and the second is a good obstacle in connection with it. For a small force the first thing to be done on arrival in camp is to mark out the positions to be taken up in order to repel a night attack. If there is only time to do this with a line of stones, it will give the defenders a definite line of defence and something to hold on to. For convenience in camping, troops should generally occupy the same relative positions each night, but this convenience must be sacrificed to the arrangements necessary for defence, as it is very important that units should camp close to the ground which they would have to hold in case of attack. In selecting a camp regard must, of course, be had to the position of the water supply. This should always be under effective rifle fire, but it must be remembered that a good position against probable night attacks is one of the first considerations. Cover for Outposts. 120. Where no natural cover exists, outposts should be Outposts entrenched. The guiding principles in the design of the defences should be : — The provision of an all-round field of fire and the protection of the garrison from reverse fire. Plate 44, shows various types of cover suitable for out- posts. Such works should, whenever possible, be surrounded with obstacles.' ■ (5289) P 50 CHAPTER XI. — DEFENCE OP POSTS, VILLAGES, ETC. Organisation for Defence of Large Positions. Defensive 121. In order to ensure a good system of command and positions. orp;anisation, defensive positions should be divided into well- defined sections, each under a separate commander, to whom should be allotted a distinct force, e.g., a division, brigade, etc. {see " Combined Training "). Each section commander will be responsible for the occupation and preparation for defence of his section in accordance with the orders received. He will either indent on the service or department concerned, or may make arrangements by hire, contract, or requisition with the local civil authorities, according to the circumstances of the case, for such extra labour, tools or materials, as may be required. For Tables, giving roughly time required for various works and form for working parties, which will be found useful in connection with the above, see pp. 120 and 136a. 51 CHAPTER XIL— TEMPORARY ROADS. 1 22. Temporary communications by road are usually Tem- required :— " vovnvy (a) In comiection with a defensive position to enable '-■°°^™^'^^" ^ ' , -,.■, -IP • cations, troops to be readily moved irom one portion to another. {b) For the movement across country of detached columns. In both cases provision will generally have to be made for wheeled vehicles, while simple means to enable the infantry to pass dryshod over water should not be neglected. The pro- vision or improvement of such communications can, as a rule, be carried out bv unskilled labour. For more permanent work see Chap. XXII, Part II. Communications inside a position will consist in repairing existing roads. filUng up soft places, cutting ramps in steep ground, cutting gaps through fences and clearing roads or paths through woods. The points to be kept in mind are : That troops should be able to move on as broad a front as possible, and that troops and messengers should be guided to their destination by sign- posts, by " blazing " trees or other means. The work in connection with detached columns will generally consist in repairing existing tracks or fords and making boggy or soft ground fit for wheeled transport. Since soft ground, even though passable, is very trying to draft animals and causes delay, a little labour, well applied, will be amply repaid. 123. The best foundation for a temporary road over boggy Tem- ground is a layer or layers of fascines placed touching one porary another ; the top row must he across the direction of the ^'^''^^^ o^^'^' traffic, but when time is not available or suitable material not gpf^nd at hand, much can be done by throwing down brushwood, heather, or even straw or grass, care being taken that this, like the fascines, is laid across the road. If there is much wheeled transport, a reserve of material should be collected to replace any that gets worn through. (5289) D 2 52 CHAPTER Xlir. — KNOTTING AND LASHINGS. In very wet ground it may be necessary to dig a drain on each side of the road {see PL 82, Fig. 3). Corduroy 124. Where timber is available and heavy traffic is expected, road. a " corduroy " road may be made. This is constructed by felling trees, cutting them to the required lengths and laying them across the road at right angles to its direction, ribands being spiked to them at either end ; or the logs may be held together by interlacing with rope or wire. The interstices between fascines, brushwood, logs, &c., may be fUled with small stones and earth to make a better surface. CHAPTER XIII.— KNOTTING AND LASHINGS. Knots and 125. The following are the most useful knots for bridging bitches. and lashing spars, and their principal uses : — (a) To make a knot on a rope, or to prevent the end from unf raying, or to prevent its sUpping through a block ; the thumb knot (Fig. 1, PL 45) or the fgure of 8 (Fig. 2). {h) To hend or join two ropes together. The reef knot (Fig. 3) for dry ropes of the same size ; the single sheet hend (Fig. 4) for dr\^ ropes of different sizes ; the double sheet bend (Fig. .5) for great security or for wet ropes of different sizes, and the hawser hend (Fig. 6) for joining large cables. (c) To form a loop or bight on a rope which will not slip. The bowline (Figs. 7 and 8) for a loop at the end of a rope, the bowline on a bigh^ (Fig. 9) for a loop in the middle, with a double of the rope. [d) To secure the ends of ropes to spars, pickets, &c., or to other ropes. Half hitch (Fig. 4, PL 46) for securing the loose ends of lashiDgs, &c. Clove hitch (Figs. 1 and 2, PL 46) (two half hitches) generally used for the commencement and finish of lashings. :FZjcct^ 4-5. KNOTS :Fiy.5. SeiscLrzg J^.9. J^oWlznje^ 5186% OB W-',£^ SB P/^.//? oO s,3e.6. OS. BRIDGES Fu/.^. Weiler&Gradam. L!r' Lirho.London OpposLte pouje 51. CHAPTER XIV. — BRIDGES. 57 141. The same nature of roadway can be applied to cacli Construc- type of bridge, and its usual form is shown in PL 50, Fig. 1. ^'^^^ ^^ The planks or chesses, A, A, placed across the width of ^^^^ ^*^' roadway are supported on longitudinal baulks or road-bearers, B, B, which in their turn rest on transverse transoms, T, T, and the method of supporting these last depends on the type of bridge. The chesses are kept steady by two ribands, R, R, which are secured to the outside baulks either by rack lashings or by lacing, or the chesses may be simply nailed down. 142. A width of 8 feet in the clear — ^.e., the clear space between Width of the ribands — suffices for infantry in fours, for military vehicles in roadway. one direction, and for c&Yalvj in. half -sections — i.e., two abreast; but 9 feet in the clear is a better width, especially when there is likely to be a sway on the roadway, as frequently happens in the case of floating and suspension bridges. The " normal " width of bridge is 9 feet in the clear. Six feet will take infantry in file, cavalry in single file, and field guns passed over by hand ; IJ feet to 3 feet will take infantry in single file. 143. Planks IJ inches to 2 inches thick are sufficient for Chesses. ordinary traffic. For continuous or heavy wheeled traffic additional chesses should be laid longitudinally, to form wheel tracks. Chesses can be economised, if they are longer than the width of the bridge, by placing them diagonally. Hurdles, short fascines, corrugated iron, &c., can be used in lieu of planks, but are not good for horse traffic. When material is available, chesses may be laid on the ground on the banks on each side for a short distance, to allow horses to become accustomed to the noise before actually getting on to the bridge. 1 4 4. A handrail should be provided, especially for horse traffic. Handrail They must be strongly built. Screens on either side are desirable and for passing animals over a bridge, especially over running water, ^^^eens. 145. In most bridges the ribands should be fairly pliant, in Ribands, order that the rack lashings may press them tightly down on the chesses throughout. In suspension and floating bridges, however, stiff ribands are desirable, as they tend to stiffen the bridge. 58 CHAPTER XIV.^-BRIDGES. Rack lashings should be applied at intervals of 4 feet or 5 feet. Baulks. 146. The number of baulks depends upon the size of the timber available. They should be sufficiently close together to support the chesses. Bays. 147. The distance bridged by one set of baulks, i.e., the distance between any two transoms, is called a hay. The length of bays depends chiefly upon the size of available baulks ; 10 feet to 15 feet is a convenient length. When the trestles are large, material and labour should be economised by making the bay as wide as the length and strength of the available road-bearers will allow. Strength 148. Whatever arm of the service it is constructed to carry, of bridges. ^ bridge should be capable of supporting it when crowded in the formation for which it is intended. Thus a bridge intended to carry infantry in fours should be strong enough to take infantr}^ in fours when crowded. A bridge that will carry infantry in fours crowded at a check wiU carry field guns and 5 -inch howitzers and most of the ordinary wagons that accompany an army in the field. Timbers of bridges for carrying heavier weights, e.g., guns of position, should be calculated {see Part II.). The following approximate dimensions for spars of unsdected timber are necessary for carrying infantry in fours crowded : — For bays of 15 feet — Road - bearing transoms, mean diameter, 10 inches. Baulks (six), mean diameter, 7 inches. For bays of 12 feet — 1 inch less than above will suffice. Other timbers not affected by length of bay : — Ledgers and handrails, mean diameter, 4 inches to 6 inches. Braces and ribands, 3 inches at tip. Legs, trestle, mean diameter, 6 inches. These dimensions are calculated for spars of rather weak wood, such as larch, and allow for a factor of safety of three. Five road-bearers are enough for selected spars. Camber. 149. The roadway is generally constructed with a sHght rise towards the centre of the bridge to allow of subsequent settle- ment ; this is technically called the camber, and should be about -^\ of the span. CHAPTER XIV. — BEIDGES. 59 150. RefTulations for the passage of troops over field bridges Precau- are laid down in " Combined Training," 1905, Sec. 27. ^ions to be With the officer in charge rests the responsibility of no j'^^^ J^^ ^^ physical obstacles occurring to cause checks or crowding on bridges. the bridge itself. The passage of troops o-ff a bridge should be always expedited, their passage on to it carefully regulated, and, when necessary, checked by material obstacles. The officer superintending the construction of a bridge is responsible that it is strong enough to support the weight it is intended to carry. To prevent it being over-strained he should place a signboard at either end, stating the greatest permissible load, thus : — " Bridge to carry infantry in fours." " Bridge to carry infantry in file." " Bridge to carry guns not heavier than 13-pr." Trestle Bridges. 151. Trestles made of spars lashed together \vith rope or Lashetl wire may be of three kinds — two, three, or four-legged. spar The ordinary form of two-legged trestles is shown in PL 50, *^^^stles. Fig. 2. 152. To make trestles for a particular bridge the centre line of Order of the bridge should be marked out on either side of the gap, and a '^ork. section of the gap laid out on flat ground showing the depth of the gap at each trestle (two sections, if the depth on one side of the bridge is different to that on the other). For each trestle the position of the lashing on the transom is dependent on the width of the roadway, and the lashing on the leg dependent on the depth of the gap allowing an outward splay of -f- The ledgers are usually lashed on about 1 foot from the bottom of the leg, parallel to the transom, their point of lashing depending on the length and splay of the leg. For a muddy bottom 60 CHAPTER XIV. — BRIDGES. Placing and bracinn; trestles. Three- legced or tripod trestles. the ledgers should be close to the butts, so as to take the mud ; for a rocky bottom they should be high enough up not to touch. Square lashings {see Sec. 129) must be used. The braces are put on the frame with both butts and one tip on the same side, the second tip on the reverse side ; their butts can be lashed simultaneously with the ledger and transom. The frame must then be squared by testing the diagonals, measuring from the centre of the ledger lashing to the centre of the transom lashing on the opposite leg, and the frame must be adjusted till these measurements are equal. The braces can then be lashed at the tips and crossing point. If the timber is weak both legs and transom can be doubled. Ledgers and diagonal braces can be of light material, as little strain is brought upon them, but they should be well lashed. When the water is very shallow the trestles can be carried out and placed by men working in the water. When the water is too deep for this they can be carried on to the bridge and lowered feet first down inchned spars to their final position, or taken out on rafts and by means of guys taken to shore tipped up into position. Two-legged trestles are kept upright by lashing the road- bearers to the transoms and by cross-bracing from each trestle to its neighbour {see PI. 49, Fig. 1), the nearest trestles to the banks on either side being rigidly connected thereto by light spars lashed to the tips of the legs and to bollards on the bank. These light spars are put on before the trestle is launched, and help to get it into position, they also serve as handrails when the roadway is placed. 153. PL 51. Fig. 1. shows three-legged trestles, two of which are required for the support of a single transom ; to make them, it is best to lash two legs together by a sheer Ipshing, open them out, and then add the third leg or prypole (see Fig. 2) ; the trestle must t' en be up-ended, the feet placed on the angles of an equilateral triangle with sides of about half the height, and thr^e light ledgers attached. The advantages of tripod trestles are that they utilise light material, will stand without bracing, and admit of more ready adjustment, raising or lowering, of the roadw^ay than either TRESTLES PLaJ^iS] s/as.s .OS . Wel («r k Gr«h««ii. Lflf U rte^^^Oon Opposite jJC^Mf^ SO. BRIDGING EXPEDIENTS. J^i^.1. I f^^i.os. Opposite pn^ 6/. CHAPTER XIV. — BRIDGES. ol of the other forms ; they are, however, unsuitable for aa uneven bottom, and extremely difficult to place, excepting by actually carrying them into position. They are usually placed from rafts when working over water, and their legs must be weighted. 154. Fig. 3 shows a four-legged trestle ; it is made of two Four- frames similar to two-legged trestles, locked at the transoms, legged and connected by short ledgers at the feet. One frame must trestles, therefore be made narrower than the other. The inclination of the legs should be such that the breadth of the base on which the trestle stands should not be less than half the height. The legs must also have an outwards splay of |. Four-legged trestles can be made of fairly light material, and will stand without bracing. They are consequently useful for small bridges of two bays,' requiring one central support, and as occasional steadying points in a long bridge of two- legged trestles. When a carpenter's tools are available, trestles may be made with iron fastenings ; they are more durable than those made with rope. Figs. 4 and 5, PL 51 are examples. Fig. 5 is especially useful when only light timber is available. 155. Communication may be rapidly established across a gap BridiJing by the method shown in PL 51, Fig. 6. In Fig. 6 two spars expe- are rested about their centres on the transom of a narrow ay. 158. The roadway of floating bridges is similar to that already described in Sec. 141 ; wide roadways are preferable to narrow ones, on account of their great steadiness. Buoyancy. 159. Each pier must have enough available buoyancy to support the heaviest load that can be brought on to one bay of the bridge. No extra allowance need be made if the load is live. The length of the piers should be at least tw4ce the breadth of the roadway for the sake of steadiness, and they may be connected together at their ends by tie baulks or lashings. The ivaterway between the piers should never be less, and should if possible be more, than the width of those piers. Floating piers may be made from specially constructed pontoons, boats, casks, or timber rafts ; inflated skins, or anything that w^ill float, may have to be resorted to on emer- gencv. Boats. 160. Open boats should not, except in sluggish water, be immersed deeper than within 1 foot of the gunwale, and a still larger limit of safety wall be required in rough water or a violent current. They should be placed in bridge " bow on " to the current, and slightly down as the stern ; or if the river is tidal they must be placed alternately bow and stern. If the boats be not each buoyant enough to form a pier, they may be used in pairs (Fig. 2. PL 53). The sterns are lashed together, and the spars AA^ BB| are held over the side ; four 2-inch ropes at AB, CD, CiDi, A,Bi, are passed under the boats and secured to the poles, and four double ropes are passed round the latter at the same points and cross over the boats ; these ropes are racked up tight. Crosspieces, MM, are then lashed to the poles and thwarts, and blocks on the thwarts I'Uilf. S3 BOAT PIERS ^^.;. ^^j^ SexitLon. Jl.JB. J^O/.Z. ^^•10^ 3 fiddle^ ^eearv W^Thj/^'ccyV SI a 6. B 05. W«ller46fah«m.L'* Lirfto,Lon«Jon. Opposite' pcLge 6Z . d M ^,1 Plate 54 CASK PIERS rtavruda SlUL^S -^F3:3ir ^rTvrrvf If- ^ :^l 7^ Szde JElevaJturn. 2n jg 8 ^^-^ Pg^"^ ^SS.Z.05. Welleri Graham. L'* LirhoLondon Opposite- paqC'SS CHAPTER XIV. — BRIDGES. 63 at EE support the saddle beam, which is lashed to the thwarts and to the stern rings of the boats. Few boats, with the exception of heavy barges, are strong enough to allow of the baulks resting on their gunwales. A central transom should be improvised, which can generally be done by resting a transom on the thwarts, and blocking them up from underneath, thus bringing the weight directly on to the kelson. This arrangement is shown in Fig. 1, PI. 53. 161. The available buoyancy of a boat may be (most simply) Buoyancv determined by loading it with unarmed men to such a depth of boats, as is considered safe, usually within 6 inches of the gunwale in sluggish streams and 1 foot in rapid, and multiplying this number by 160. The result gives the available buoyancy in pounds. 1 62. The usual method of forming a number of large casks Piers of into a pier is shown in Figs. 1, 2, and 3, PL 54. The casks are ca»iks. laid bung uppermost, and Hned, two baulks technically known as gunnels (GG) are placed over the ends, and the slings (SS) are secured under the ends of the casks to - the gunnels. Between each pair of casks, on each side, a brace is secured on the shng, and is then led round the gunnel ; the opposite braces are crossed and secured again on their own side. A knot must be made as shown near the standing end of the braces to prevent tbe crossed parts shpping. Care must be taken that the braces are pulled taut ; this is best done by rocking the barrels, at the same time hauling in the slack. For large piers the shng should be 2J-inch to 3-inch rope, the braces can be of IJ-inch rope. (For a detailed description of this method, see Part II.). 163. Fig. 4 suggests a method useful for smaller casks. Small piers of three or more casks, aa, bh, cc, being made as above described, and subsequently united by two large gunnels, X, X. 164. Figs. 5 and 9, show another method useful for medium- sized casks. The braces are first fastened to a gunnel and stretched out perpendicularly to it ; the casks are then placed in two rows, end to end, on each side of the baulk and over their own braces. On the casks are laid two gunnels, loosely lashed together at the ends and at one or two intermediate points, 64 CHAPTER XIV. — BRIDGES. the distance between them being less tlian a bung diameter, the braces are then secured to the gunnels by two round turns and two half-hitches ; the lashings connecting the gunnels are then racked up, and finally the two at the ends are secured to the underneath baulk by lashings, which are also racked up taut. Other methods can be readily devised according to the material available, e.g., the cask can be completely enclosed in a wooden framework, the parts of which are lashed or nailed together {see Figs. 6, 7, and 8. Tie baulks. 165. Piers of casks when in bridge should always be rigidly connected to each other at their ends by tie baulks, which must be lashed to both gunnels of each pier ; the roadway baulk? can then be laid, without lashing if rectangular ; they should rest on both gunnels of each pier. If, however, the baulks are round, or there is likely to be much sway on the bridge, and especially for animal traffic, it gives additional security to lash, at any rate, some of the baulks both to each other and their overlap, and also to the gunnels. Headless casks must be enclosed vertically in a specially prepared framework. To form 166. To form a raft, the logs should be placed side by side, a raft thick and thin ends alternating ; they should then be strongly secured with rope, and, if possible, by cross and diagonal pieces of timber fastened by spikes or wooden trenails ; or the logs can themselves be connected by dogs. If a raft is to be used as a pier in a bridge, it will frequently be necessary to place the logs in two layers, to avoid obstructing the waterway. A central raised transom must be used. The up-stream end of the raft may, with advantage, be slightly convex. Rafts are most easily put together and manipulated in the water. Anchoring 167. Anchors are of various weights. For ordinary bridge of bridges, work 5G-lb. anchors, with a reserve of 112-lb. anchors, will generally suffice for moderate streams. The cables are generally of 3-inch rope. The length of cable " out " should be ten times the depth of the stream, and rarely less than 30 yards. The cable is attached to the ring of the anchor (PI. 55, Fig. 1) by a fisherman's bend ; a buoy should I I'/'rt^> 55. ANCHORS ^^.^. CrownX — ^ IFigr.S Fi^.^. 5/86. S 05. Wwlertirfltism.L" Li>t>ci,Londoo Opposite pcfj^e- 65. CHAPTER XIV. — BRIDGES. 35 be attached to the anchor by a buoyline of l-inch rope, fastened to a ring of the buoy by a fisherman's bend, and round the crown of the anchor, with a clove hitch split by the shank, and two half-hitches round the shank. The use of the buoy is to mark the position of the anchor and serve as a means of raising it. As a rule there should be an up-stream and down-stream anchor to every second pier of a floating bridge. If anchors are scarce, one may be made to serve for two piers by attaching two cables to it on the down-stream side of the bridge, as shown in Fig. 2. Care must be taken before heaving an anchor overboard to see that it is carefully stodced. Timber raft« and cask piers being, as a rule, a greater strain on anchors than boats or pontoons. In d very rapid current, anchors can seldom be trusted. The bridge must then be secured to a hawser stretched across the river " up-stream.*' Wire rope is convenient for the purpose (Fig. 3). Short bridges can be kept steady by cables stretched from the piers to the banks, up and down stream (Fig. 4). 168. The following are substitutes for anchors : — Makeshift Two or more pickaxes lashed together. anchors. Heavy weights, such as large stones or railwav irons ; the latter are best when bent. Nets filled with stones— remarka^bly effective on rocky bottoms. 169. X bridge can be formed by booming ov.t, i.e., the head Methods of the bridge already constructed is continually pushed out o''^"o?''^'ng into the stream, fresh materials being added at the tail. This ?°^^^^° method economises the distance the materials have to be BoomiiT^ carried, but necessitates a certain number of men working out. in the water, and cannot be used vrhen the banks are steep, and there is deep water close in shore, as for instance, in the case of a wharf wall. In for thing up. material is continually added to the head Forming of the bridge, the tail being stationary. This method is up. uninfluenced by the nature of the banks, no men being required to work in the water. Its only drawback is the distance the roadway materials have to be carried. (5289) T, I GG CnArTER XIV. — P.TIIDGES. Bafting. Swinging. Forming cuts. Protection of floating bridges. Passage of heavy artillery. Passage of arms and ammuni- tion. Ferries and flying bridges. In rafting, the bridce is put toiretlipr in difTeront pcrtionp or ■rajt? along the shore, each raft consisting of two or morn piers, which rafts are successively warped, rowed, or towed into their proper positions in bridge. This method has the advantage that a large number of men can be employed simultaneously ; and if secrecy b?5 an object, the various portions can be constructed at some distance from the eventual site of the bridge, and a favourable oppor- tunity seized for its construction. In swinging, an entire bridge is constructed alongshore, and then swung across with the stream. A long bridge can be constructed by a combination of two or more of the above methods. If a bridge has to remain down for some time, arrangements must be made for the passage of the river traffic, which can be done by having two or more rafts, at the centre of the bridge, arranged for " forming cut " as required ; or the two halves of the bridge may be swung, to afford the requisite passage. 170. Arrangements must always be made, up-stream, for the protection of a bridge from damage by floating substances, either by a boat patrol or by stretching a net or some inter- cepting obstacle acioss the stream. 171. If heavy siege artillery has to be passed over a broad river it will generally be most economical of m.atcrial to con- struct the bridge of only sufficient strength for the ordinary traffic, and to warp the guns across on rafts constructed of sufficient strength for the purpose. 172. To keep rifles and am.munirion dry when men swim across a river, small rafts can be made of w;iterproof kitbags filled with straw, blown-out ma'^aks (water-skins), cooking kettles or any similar vessels, which should be placed mouth downwards. The simplest form of permanent ferry consists of ropes stretched across the river by means of which rafts can be sheered or hauled backwards and forwards from bank to bank. If it be not convenient, for the sake of traffic or other reasons, to stretch a rone across the stream, recourse may be had, if the current is rapid and regular, to a flying brid<7e, which is one in which the action of the current is made to move a boat or N P(xrf€.^e. FORDS & FLYING BRIDGES ^ Stream^ ^^*^ tP- 7^^-^. y VMIerii&r»t>a« 'C* li>(M.Lon(ton ()ppcsxjb& Jiaxfp^ 67, CHAPTER XIV. — BRIDGES. G7 raft across the stream by acting obliquely against its side, which should be kept at an angle of about 55° with the current. (PI. 56, Fig. 3.) Long narrow deep boats with vertical sides, to which lee boards can be attached, are the best for the purpose, and straight reaches the most suitable places, as they are generally free fiom irregularities of current or backwaters. The cable, which should, if possible, float, such as coir rope, can either be anchored in mid-stream, in which case the raft can swing between two landing piers ; or two cables may be used, one anchored on either bank, as shown in Fig. 2. This method requires less skill in manipulation, but necessitates two cables and four piers. The length of a swinging cable should be one and a half to two times the breadth of the river, and it will work better if supported on intermediate buoys or floats to prevent it from dragging in the water. Telegraph wire, buoyed up as above, on meat tins, makes a good swinging cable. Another way is to stretch a wire cable across the river, and arrange the raft so as to travel along it {see Fig. 4, PI. 56). 173. The following depths are fordable : — • I'unls. For infantry, .3 feet. For cavalry, 4 feet. Artillery, 2 feet 4 inches. Gravelly bottoms are best, sandy bottoms are bad, as the sand gets stirred up, and the depth of water thus increases. Fords should be clearly marked by long pickets driven into the river bed above and below the ford, their heads being connected by a strong rope. It is well to mark the pickets in order that any rise of the water may be at once evident. The depth of a river is generally most uniform in straight parts ; at bends the depth will generally be greater at the concave bank and less at the convex. Thus, in PI. 56, Fig. 1, the depth will probably be above the average at C and F, and there will be shallow spits at D and E. For this reason a river which is not anywhere fordable straight across may be found passable in a slanting direction betweer two bends, as at A B, Fig. 1. (5289) E 2 68 CHAPTER XV.— CAMPING ARRANGEMENTS. Cooking. Field kitchens. Covered kitchen. Expedi- ents. Kettles. 174. To cook for a large party, the most economical method is to dig or build up a long trench for the fire, place the kettles on it (its width not being sufficient to yllow them to drop into it), and cover up between them with stones and clay, that the fire, fed from the windward end, may draw right through. A chimney can be built at the other end to increase the draught. The section of a typical trench for this purpose is shown in Fig. 1, PI. 57. The chimney can be built of sods, and is supported where it passes over the trenches, by flat stones, slates, wood covered with clay, &c. The inside of the trenches and of the chimney may be plastered with clay, which makes them last longer. Several such trenches may be combined, as shown in Fig. 2, to form what is known as the "parallel or rectangular kitchen, or three trenches may converge to one flue, as shown in Fig. 3, forming what is known as the broad arrow kitchen. 175. The gridiron kitchen (Aldershot pattern) is shown in PL 58. 176. PI. 57, figs. 4 and 5, gives details of a covered kitchen, suitable for standing camps. The roof may be covered with tarpauhns, or in the manner described in Section 193. 177. For a small party the cooking may be done by digging a shallow trench, in the direction of the wind, to contain the fuel. Small pieces of iron will be found very useful to support the kettle. Another way is not to excavate the ground at all but to build up two rough walls of stones on the top of which the kettle is placed. The simplest and best arrangement for cooking in the field for any party over 20, especially if the stay in camp is only for one night, is to place a porportion of the kettles on the ground in two parallel rows about inches apart, handles out- wards, block the leeward end of the trench so formed w4th another kettle, lay the fire and place over it one or two rows pf kettles resting on those already placed in position {see PL 59). JPlccte.51. KITCHENS. riy.z Seotvo RECTANGULAR CvoJcj f»f V'.ft-i BROAD 3 A? ftten. ARROW COVERED KITCHEN \f^'\\ Tr^.^. i'^:^!^ Ti^.5 WeU«r«,«ireh««.L'* liH>O.U>«««r Opposite pciqe S8, J^lat^5ti GRIDIRON KITCHEN I'Zjr^.?. up!'^^ a ^/ ¥:r ii A^ .^f1 p ^!-f-'?---:-jf-*'---^-'ii 1 — n /\ /\ /\ /\ /\ /\ / \J\ ^rervchy 36 '^2'' X 7 'S oi&^pff JPVy.^. ALDERSHOT OVEN J^z^.S cae 8 OS welter &€r«h4n.L" LitftoLondon 7h foZlcnv plate 37. Plate f 3. COOKING IN THE FIELD Fiff.l. >.^^> -^'■ ™.^.'-. " -~>tK*/ V/e l le r < --->■ •^jTjjr.^. >; -i* ♦,' ^^-? :Pljajv -i j^.S. «« g- Wef1tr«i6f«h«m, L'f Lirho.Lon^on To fblZo^ plate 59. CHAPTER XV. — CAMPING ARRANGEMENTS. 69 Mess tins can be arranged similarly, but in their case not Mess tins, more than eight should be used together. 178. The simplest form of a field oven consists of a hearth Field sunk below the ground surface, with, an arch formed by a hurdle o^^^ns. or sheet iron {see ?1. 60). The two gable ends are formed with sods. The whole of the interior of the oven is well plastered with cowdung and clay. The hurdle, well plastered on the outside with cowdung and clay so as to leave an arch when it burns away, is covered with earth from the excava- tion. The entrance to the oven is closed either by a hurdle plastered with '^]ay or simply by sods. This oven is specially suitable for making bread, and will bake for about 150 men at a time. Figs. 5, 6, and 7 show an oven with a flue underneath an iron hearth. The oven is first heated by lighting a fire inside it, and this is afterwards raked out and pushed into the flue below to maintain the heat. It is a very useful oven for baking or keeping men's dinners warm. The service oven, Aldershot pattern, should be fixed up without the flue, but placed on a prepared flattened site. Latrines. 179. Latrines should be made as soon as troops arrive on Latriues. the ground ; a small shallow trench will suffice for one night ; and should be invariably filled-in in the morning, before the troops march oS. In standing camps latrines may be made with seats, the seat being a pole (see Figs. 1 and 2, PI. 61) ; additional comfort may be given by adding a top pole to form a back, as shown. Other forms are shown in Figs. 6 and 7. In order to keep out flies latrines, where practicable, should be closed in and made as dark as possible. Latrines should be constructed to seat if possible at least 5 per cent, of the troops, 1 yard per man being allowed. The trenches must be narrow and deep to prevent the contents being blown about. When natives are employed special latrines for them are necessary. 70 CHAPTER XV. — CAMPING ARRANGEMENTS. It is very important that a couple of inches of the driest earth obtainable should be thrown over the soil twice daily ; this, if carefully done, will prevent all smell and tend to prevent flies collecting. The earth may be dried by pihng it close to the trenches of the field kitchens. Lime or charcoal may also be used to deodorise the soil in the trenches. On leaving camp the site of latrines should be carefully marked. Too much care cannot be bestowed in selecting the site of the latrines; since flies are very active agents in propagating diseases, latrines must be placed well aw^ay from cook-houses. Care must be taken that no filtration from them may reach the water supply. Water Supply. Wator 180- Each man requires for drinking about 3 to 4 pints per supply. diem; for drinking and cooking, 3 to 4 quarts; for drinking, cooking, and washing, 3 to 4 gallons. Each horse requires for drmking 5 to 10 gallons, according to work and chmate, soft water being the best ; for cleaning, 6 to 8 quarts (which may be salt). Each mule or ox drinks G to 8 gallons ; each sheep or pig 6 to 8 pints. These are minimum quantities. Horses drink about I J gallons at a time. In calculating troughing, allow each horse five minutes at the trough. ^.B.—See also " Combined Training," 1905, Sec. 43. One cubic foot of water = G^ gallons (a gallon = 10 lbs.). Pleasure- 1 81. The rough average }4eld of a stream may be measured as iiient ot follows : — Select some 12 yards or 15 vards of the stream ..; -.1 .1 ... where the channel is fairly uniform, and there are no eddies. Take the breadth and average depth in feet in three or four places. Drop in a chip of wood and find the time it takes to travel, say, 30 feet. Thus obtain the surface velocity in feet per second. Four-fifths of this will give the mean velocity, and this multiplied by the sectional area in square feet will give the yield per second in cubic feet of water. quantity ivquiivd yield. rCucteGJ LATRINES S' 3 rr -^ . 4-. M 38 Z ss J-^g.5. Section^ 6/./^. "sias 8.0S Opposite p<^^ 70 CHAPTER XV. — CAMPING ARRANGEMENTS. 71 The source of the water supply should be carefully in- Source, vestigated, and measures tiiken to prevent the pollution of the water en route to the drinking supply. 182. In the field the supply is usually obtained from sources which are at once available, such as streams, ponds, or existing wells. In default of these it may be necessary to sink wells and make reservoirs. Surface springs should be sought for in hollows, at the Surface foot of hills, where the earth is moist or where the grass is springs, unusually green, where the thickest mists rise in the mornings or evenings, &c. 183. If the supply be from a lake, pond, or stream, separate Protection watering-places for men and animals must be marked out and <^t" tlie sentries posted. Stagnant water, as in a pond, is apt to be ^^^^^^^ ^' contaminated by large numbers of animals going in to drink ; and even in a stream, when many animals are drinking, those below get foul water. If possible, therefore, the water should be drawn from the source and run into drinking troughs ; these are best made of canvas or of boards ; but trenches lined with puddled clay answer the purpose. 1 84. The overflow from the troughs must be carried ofi with the surface drainage. The sites of the troughs should, if possible, be paved and drained for a width of 10 feet, and should be so arranged that the animals may move to and from them without confusion or crowding, arriving from one direction and leaving in another. Each horse occupies laterally 4 feet ; if possible, all the horses in a camp should be able to be w^atered in an hour. When troughs cannot be made, the banks should be cut down, and a hard bottom formed on the ramp to prevent the animal from sinking in. A barrier may be placed in the pond to prevent them from going out too far. The water should not be less than 5 inches or 6 inches deep where beasts are to drink. 185. In a stream the men should draw w^ater above the place Supply for the animals ; while washing, &c., should be done below, ^'"'^"^ and drainage should enter below the others as far down stream ^ '**''^"^*- as possible. Barrels sunk in the bed of a small stream afford convenient dipping places. from spring 72 CHAPTER XV. — CAMPING ARRANGEMENTS. Supply 186. If the supply be from springs, each springhead should be opened up and surrounded by a low puddled wall to keep out surface water. Casks or cylinders made of brushwood, like gabions, make good linings for springs. After they are placed, puddled clay may be worked down between the banks and the cask or cylinders. The overflow may be received into a suc- cession of casks or half barrels (which may with advantage have their insides charred) let into the ground close together, the overflow from the first passing into the second, and so on ; or deep narrow tanks with puddled sides may be constructed to catch the overflow. Water from small ponds and shallow wells should be avoided, if there be a choice. P^- 187. The lift and force pump is in most general use in the service. It is worked by two men. It can lift water from a depth of 20 feet to 28 feet, and force the water to a height of 60 feet from its former level, dehvering 12 gallons per minute. Purifying Water. Boiling. 188. The best method of purifying water is by boiling. It gets rid of temporary hardness, renders dissolved organic matter harmless, and when carried out effectually practically destroys all micro-organisms. The water should be kept at the boil for at least five minutes. Boiled water should be aerated before use. This can be done by passing through a sieve. Improvised methods can be arranged according to the means at disposal. Empty biscuit tins pierced with small holes suspended over a storage tank do very well for this purpose. Care is necessary to prevent the addition of fresh impurities during aeration and distribution, riltraiion. 189. As it is not always possible to provide means of boiling water on a large scale, filtration must be resorted to. Formerly mechanical filtration only was attempted and a clear sparkling water was considered good. Efforts are now CHAPTER XV. — CAMPING ARRANGEMENTS. 73 directed to remove meclianical and chemical impurities as well as micro-organisms. Several filters have been brought before the public, all claiming to effect these purposes. The type most familiar is the " Berkefeld " filter. These filters, if treated with care and strict attention to detail, work satis- factorily. Their chief defect is a very slow dehvery when water containing a large percentage of suspended matter is used. The porcelain candles become almost impervious when coated with fine mud and constant cleaning is necessary. This, however, is an easy process. Dirty water should be strained before filtering. A good method is to tack a sheet on to a wooden frame so as to form a bag or basin ; put a couple of handfuls of wood ashes in the bottom, and then pour on the water, allowing it to percolate into a receptacle beneath. 190. Chemicals are sometimes added either : {a) to precipitate Addition suspended matters ; [b) to remove hardness or ; (c) to oxidise ^^ organic impurities, {a) Muddy water may be cleared by adding ^ ^^^^^^^ ^• alum. Six grains of crystallised alum per gallon is sufficient. It should be added some hours before the water is required. [b) Water can be softened by the addition of Hme water for drinking and carbonate of soda for washing purposes. The latter is unsuitable for drinking water as it gives an unpleasant taste, (c) Permanganate of potash (Condy's fluid) removes offensive smell from water and to some extent oxidises dissolved organic matter. It should be added until a faint tint remains permanent. It has not a disagreeable taste. Shelters and Huts. 191. Bivouacs are but seldom resorted to except in the neigh- Bivouacs, bourhood of an enemy, when miUtary rather than sanitary considerations are of primary importance. The following are the chief points to borne in mind in determining the sites for bivouacs : — In the presence of an enemy, tactical considerations, e.g., Choice of favourable ground for defence in the event of attack, conceal- ground 74 CHAPTER XV. — CAMPING ARRANGEMENTS. ment, facilities of protection, and consequently, economy in outposts are of the first importance. The comfort of the troops, in conjunction with sanitary conditions, is the next consideration. A good water supply is essential, but considerations of safety may necessitate a camp or Livouac being placed at some distance from it. Other points to be considered are the facilities which a site offers for obtaining shelter, fuel, forage and straw. The site for a camp or bivouac should be dry, and on grass if possible. Steep slopes should be avoided. Large woods with undergrowth, low meadows, and newly turned soil are apt to be unhealthy. Clay is usually damp. Ravines and watercourses are dangerous sites, as a sudden fall of rain may convert them into streami.s. If the occupation is to be of a permanent nature, as in investment warfare and the defence of strategical points, the men ought to be hutted. Tem- 192. PI. 62 suggests methods of forming simple shelters, porarv Yis. 1. Two forked sticks driven into the ground with a pole restmg on them ; branches are then laid resting on the pole, thick end uppermost, at an angle of about 45"^, and the screen made good with smaller branches, ferns, &c. A hurdle may be supported and treated in a similar way. Fig. 2. A waterproof sheet, blanket, or piece of canvas secured by poles and string. Fig. .3. A tent (Tabri for four men, formed with two blankets or waterproof sheets laced together at the ridge, the remaining two blankets being available for cover inside. Fig. 4. A wall of straw or reeds nipped between two pairs of sticks, tied together at intervals. Figs. 5 and 7. Sentry box for standing camps. When no other materials than earth and brushwood are available, a comfortable bivouac for 12 men can be formed by excavating a circle with a diameter of 18 feet, or there- abouts, and piling up the earth to form a wall 2 feet or 3 feet high. The men lie down, like the spokes of a wheel, with their feet towards the centre. Branches of trees, or brushwood stuck into the wall, improve the shelter. shelters. L V ^W^ex^ BIVOUACS. :Fzff.i. SFig.Z'. STteZce?^ Terut :Fcgr.3. ^^■^' ^rv:>7ft. of T-ourLdySooo sias 3. as Opposi/^. page 74 Plojte 63. HUTS. ^7^anrk4s. THATCHING ?ra^ siee i .OS. Plate ^4 HUTS \^^ : ^'.'n <■ ' -"', f-, f I -* ■? -, » ' -r^ '^'^ pieces -?'"Y J±^Z,ou7y SIB9. a.os. WcilerAGratiam. LH Litho. London. CHAPTER XV. — CAMPING ARRANGEMENTS. 75 193. The materials of which huts are made depend upon the Huts, resources of the locality, and are principally brushwood, logs, straw, reeds, clay, turf, and stones. The best form of hut is generally rectangular in plan, with Plan, sufficient width for two rows of beds, and a passage down the centre, but, where the material available is of small size, one row of beds may be provided, or the hut may be made of circular form. A width of at least G feet should be allowed for each row of beds, and the passage may be from 2 feet to i feet wide. The accommodation may be calculated on active service Accommo. at one man per foot in length of the hut, when there are two ^^^^o"- rows of beds, and one man to every 2 feet when only one row on beds. Fig. 1, PI. 63, shows how the ordinary 6-foot hurdles may be arranged to form a hut. A fascine at the ridge, with thatching of straw, reeds, &c., may be used as roofing. Hurdles may be made of special dimensions for hutting Hurdles, purposes. Fig. 2 shows how a hurdle 10 feet long (measured on the curve) may be made into a hut. The hurdle is constructed on a curve slightly flatter than that it is intended to have, so that it is necessary to spring it together to get it into position. It is then secured with pickets, and covered with sods, or daubed with clay in the manner described in Sec. 195. The ground forming the floor of the hut may be sloped as shown before putting on the hurdles. Hurdles for hutting purposes should have the ends of the pickets cut off as close to the web as possible, so as to leave no gaps between them. 194, When brushwood of 2 inches or 3 inches diameter and Brush- 14 feet or 15 feet long is available, a hut for a double row of wood, beds may be made as in Figs. 3 and 5. The section of the hut being decided on, is laid out on the ground ; from this the length of the rafters is obtained. Each side of the roof is then made separately on the ground as follows : — Poles of 2 inches to 3 inches diameter are laid on the ground parallel to each other, from 18 inches to 2 feet apart, as aa, in Fig. 4, PL 63. These form the rafters. On the slope of the 76 CHAPTER XV. — CAMPING ARRANGEMENTS. ixiaterial. Passa*. rafters, and at right angles to them, hght rods or laths, hh. from -J inch to I inch thick are laid, the uppermost one being at such a distance from the bottom of the poles as will allow the frames^ when made, to lock at the desired height above th^^. ground, the lowermost one being within a few inches of the bottom, and the interval between being divided according to ll-e length of the thatching or covering material. The distance apart of these laths should be slightly less than half the length of the covering material, so that the latter may be supported i.t three points. With good wheaten straw the !nterv:il may be from 12 inches to 1^ feet. At each point of crossing the laths and rafteis are secured by a short length of one strand of spun yarn, and the frame thus made is afterwards stiffened by diagonals lashed underneath. The roofing material, which may be unbroken straw, rushes, long ferns, &c., Is now put on. Commencing at the bottom, a layer 4 inches or 5 inches thick is equally laid over the three lowest laths, ears or tops downwards ; it is here secured by a light rod or thatching piece tied with spun yarn at intervals of 2 feet or 3 feet to the second lath from the bottom. A second layer is now put on one lath higher up, and is secured in a similar w^ay to the third lath from the bottom, and so on until the top is reached ; the last layer projecting over the top lath, so that when the frames are locked the ends may be twisted together to keep out wet (Fig. 6, PI. 63). When both frames are ready they are raised and locked, as in Fig. 3. Forked uprights and a ridge piece may be added to stiffen the roof. Each side of the roof may be made in one piece, or if large and inconvenient to move, in two sections. The ends of the laths should project about 2 feet beyond the extreme rafters, and are supported by the framework forming the Gable ends, Fig. 5. The latter are made and thatched in a similar way to the roof, and simultaneously with it, an opening being left for a door. In order to give additional headway, the passage may be sunk as in Fig. 3, with steps at each end, the earth being thrown to the eaves as additional protection, and to give more head room when lying down. In very cold weather the whole interior of the hut may be excavated, fireplaces constructed CHAPTER XV. — CAMPING ARRANGEMENTS. 77 as in Fig. 1, PI. CA, and, if the rafters be strong, some of the excavated earth may be thrown on to the top of the roof, a collar tie being added to strengthen it. Huts may also be thatched by forming the straw or grass into Panels. panels. The straw in moderately thick layers is doubled and nipped near the centre between two rods, one above and one below, which are tied tightly together at the ends and at intervals of about 6 inches. The panels formed thus are tied on to the roof, being placed so as to overlap hke large slates. 195. Walls may be constructed of ivattle and daub, i.e., Wattle continuous hurdle work daubed over on one or both sides with «^f^ daub clay, in which is a proportion of any fibrous substance, such ^'^*^'^' as straw, grass, horse hair, &c., chopped into short lengths to prevent the clay cracking and opening as it dries. This mixture, which should be kneaded into the consistency of a stiff paste, should be worked in with the hands. The sides should be strutted at intervals to resist wind, and the roof mav be carried on a ridge pole, which may be strengthened by uprights in the centre, Fig. 3, PL 64. 196. When timber is abundant, log huts maybe constructed Log huts, as shown in Fig. 4, PI. 64. No fastenings are required beyond some trenails (wooden pegs) to secure the rafters to the top logs. The roof may be made as already described, or the covering material may be of slabs of wood, bark of trees, &c. Bark may be got off trees in large strips by cutting round the tree with a knife at intervals, say, of 4 feet ; then cutoff width required, and beat with a flat piece of wood to detach the bark from the tree. 197. When straw is issued for the troops to he upon, it may Straw be made up into mats in the manner shown in Pis. 65 and 66. "^at?. To make the mat shown on Fig. 1, pickets are driven into the ground, the outside pickets being at a distance apart about 6 inches less ttan the width of the required mat. A crossbar, AB, is fixed about 2 feet from the ground. Several lengths of spun yarn are then taken and made fast, about their middle, to the crossbar, AB, at a distance of 5 inches or 6 inches apart, and their ends made fast to the bar, CD, and to the other pickets, as shown in the figure. Handfujs of straw 70 CHAPTER XVI. — HASTY DEMOLITIONS. rather longer than the width of the mat are taken and pushed in between the yarns, and the bar, CD, being alternately raised waist high and depressed to the ground, and passed inside and outside the end pickets, so as to form a hitch. Finally, the sides of the mat are trimmed to the right size by a sharp pair of scissors or a knife, and the yarns finished off at either end with reef knots. Straw The mat shown in Figs. 2 and 3 is formed by making ropes. straw ropes and interlacing them on pickets driven into the ground. If the straw ropes are carefully made, this makes a more durable mat than the previous one. (PL 67.) CHAPTER XVI.— HASTY DEMOLITIONS WITH EXPLOSIVES. Explosives. Explosives 198. The service explosives available for hasty demoHtions th^Tlrf" in the field are guncotton, gunpowder, cordite ; guncotton being specially carried for this purpose. Dynamite may also some- times be obtained locally. Coin- For hasty demohtions guncotton is by far the best of the parison of service explosives. Its chief advantages over gunpowder Guncotton ^^^ *^^^ ^^^ equivalent effects a guncotton charge takes up and much less room, and does not require the same amount of powder. tamping* ; it is therefore much more easily and quickly placed and fired, which is an important point in hasty demohtions. * "Tamping" is covering tha charge over with earth or other material so as to confine the gases at the commencement of the explosion, and thus develop their force more fully. Plate. 65. STRAW MATS MALAY HJTCH STRAW ROPE MATS ^^J7- ^ ^^.3. J*Lckjsts G'apccrt. "VTsr. WielleriCrabam.Qf Utho.Loftdon. Plaix.66, MAKING STRAW MATS jBfeM Wel'erA Graham L^r Litho,London. To foUvyv j>hx±c. S5 ^Zcote, 67 MAKING STRAW ROPE *&g i •S. Welier fc Graham. Lff Lirti6.Loodon Tc fellow pLocte 6^ CHAPTER XVI. — HASTY DEMOLITIONS. 79 Guncotton is also safer in transport and handling. Cordite and dynamite are nearly as powerful as guncotton, Cordite and have the above advantages over gunpowder, but are not ^"^ so safe m transport. Where a lifting and shaking effect is required, gunpowder is best. Where a cutting or shattering effect is required, which is most likely in hasty demolitions, guncotton, cordite or dynamite are best. Guncotton. 199. Guncotton, if steeped in water, will absorb about ProporMes 30 per cent, of its weight. ^^ ^^'©t Wet guncotton does not ignite easily, and requires the ex- ^^"^^^^ °"' plosion of a very large amount of detonating substance, such as fulminate of mercury, in contact with it to detonate it. Dm guncotton will not detonate in the open in small quantities Properties if a light be set to it, nor if a bullet strikes it when not heated. °^ ^^^ It will detonate if it is struck between two hard substances. ^"^°° If dry guncotton, especially when finely divided in the shape Sensitive of fluff, becomes heated in any way (through friction or the T^^^I^. heat of the sun) it is much more sensitive to percussion. If a small quantity of detonating substance such as fulminate Means of of mercury be exploded in contact with dry guncotton, it will detonating detonate with great violence, and also cause the complete ^^^ detonation of any wet or dry guncotton with which it is in ^^^^^ contact. The explosive force of wet guncotton is slightly greater than that of dry. So that for safety in transport, &c., in the field, the bulk of Carried guncotton is carried and used wet in the shape of " slabs^ ^®^- For detonating this, dry guncotton is also carried in the shape of small discs called " primers''' The following table gives Primers, the dimensions of the slabs and primers for land service : — Slabs are issued in two sizes, about 6 inches square, weighing 1} and 14 lbs. respectively. Primers are also issued in two sizes, weighing 1 oz and 2 ozs. respectively. 80 CHAPTER XVI. — HASTY DEMOLITIONS- The slabs have two holes in them, one to fit the 1 oz. primer and the other the 2 oz. primer. Cavalry pioneers carry special 1 lb. slabs. Primers are carried dry in airtight tin cyhnders. Use of wet For auger holes and for necklaces round timber, dry gun- and dry cotton primers form the charge. Otherwise the charge is S"^^^"'^"- always of wet slabs. Details. The slabs can be cut without danger with a sharp knife or saw, care being taken to press the guncotton between boards whilst it is being cut to prevent it flaking away. There is a special clamp in the R.E. equipment for doing this. The guncotton should be kept damp. ]\reans of A charge of wet guncotton is detonated by means of the detona- explosion of a dry primer in close contact with it. The primer *'^®°' is exploded by means of a " detonator," the detonator is detonated by means of either " safety " or " instantaneous fuze," which is lit by a fusee or other means. (For details of detonators, fuzes, see Sec. 205 and onward.) Tinpro- If dry primers are not available, a piece of wet guncotton rised can be dried hy exposure to the sun, and used instead, primer. Connect. 200. A charge is connected up for detonation as follows : — ing up for '£\iq fuze (safety alone or safety wdth instantaneous) is cut to the required length. The end to be ignited is cut on a slant to expose as much of the composition as possible. The end to be inserted in the detonator is cut straight across. The straight cut end is then gently inserted into the open end of No. 8 detonator, from which the paper cap has been torn. This end of the detonator is then slightly bent (or with new-pattern detonator, pinched) to make it grip on the fuze and so prevent its being withdrawn. (Cavalry pioneers carry detonators with a short length of safety fuze ready fixed, the fuze having a piece of quickmatch added to the end to facilitate lighting.) The primer having been placed in close contact with one of the slabs of the charge, either in one of the holes or tied to a slab (see that the primer is dry), the small end of the detonator is gently inserted into it so as to fill the entire length of the hole. If the hole is too large, a piece of paper or grass must detoiia tion. CHAPTER XVI. — HASTY DEMOLITIONS. 81 be wrapped round the detonator to make it fit tight ; if too small, it must be enlarged with the rectifier* or piece of wood, Rectifiers. but not with the detonator. The charge must he in dose contact ivith the object to he de- Arrange- molished, and all the slabs must he touching each other. n^ent of Where the charge is a very long one, more than one detonator " ^^^S®- should be used. The charge must extend across the whole length of the object placing of to be cut. charge. Arrangements must be made to prevent sparks from the fuze falling on it and so setting it alight instead of detonating it. For calculation of charge, see Chapter XXI. Amount of charge. Gunpowder. 201. Gunpowder is not so suitable for hasty demolitions as Details, guncotton. and the larger the grain of the gunpowder the less suitable it is, owing to its slow burning. Except the larger grained prism and moulded powders, which are packed in cases, it is usually carried in barrels, the powder being contained in a waterproof bag inside the barrels. Powder is usually fired by safety or instantaneous fuze. Ignition. A gunpowder charge should be made up in as compact Making up a form as possible, and if sandbags filled with earth are used t!iechargf. to tamp it, the charge should be of the same shape as the sand bags. A service sandbag will hold about 40 lbs. of gunpowder, which is about as much as a man can carry conveniently. When a charge has to be placed under fire, and the amount is greater than this, it should be divided amongst several bags, as required, rather than put into one large one. In this case only one bag need be fuzed. * Eectifiers arc boxwood implements supplied for enlarging tlie per- forations in guncotton primers so as to take the shanks of detonators. (5289) V 82 CHAPTER XVI. — HASTY DEMOLITIONS. Connet- A gunpowder charge should not, as a rule, be spread evenly ing up along the whole breadth of the object to be destroyed, but '"■■'^'* should be divided up into portions, which may generally be ignition ^^ ^ distance apart of twice the thickness of the object. The several portions must be fired simultaneously. In the case of a stockade or fort gate, one concentrated charge will make a breach wide enough to admit of easy entrance. Amount of For the amount of charges suitable, see Chapter XXI. fharge. Cordite. Supply. 202. Cordite can be used instead of guncotton or dynamite. It may be obtained from gun cartridges, and would only be used where no other explosive is available. Making up It must be detonated with a guncotton primer, and the charge. cordite should be tied up in a tight bundle with the primer in the centre. The primer being connected up with No. 8 detonator and fuze as described for guncotton. Its successful detonation is rather uncertain. Placing As with guncotton, the charge must be in close contact with charge. the object to be demohshed. The cordite must be covered up with fresh grass or leaves to prevent the sparks from the fuze setting it alight, which happens very easily. Amount of As for guncotton, see table, Chapter XXI. charge. Dyxamite. Supply. 203. D}Tianiite, where procurable, can be used instead of guncotton. For military purposes the only advantage that dynamite has over guncotton is, that being plastic it is easier to fit into narrow and irregular holes such as are used for blasting rock. CHAPTER XVI. — HASTY DEMOLITIONS. 83 For demolishing masonry it is not so good as guncottom,. as its action is even more local. It cannot be used after exposure to wet, which separates General the nitro- glycerine and makes it dangerous. properlies. It freezes at 40° F., and remains frozen at higher tempera- tures. Frozen dynamite can be distinguished by being harder than unfrozen, by being more brittle than plastic, and being of a slightly lighter colour. Frozen dynamite should if possible be thawed before use. It cannot be usad when frozen as it will not detonate readily, though it will explode bv simple ignition. IT MUST NOT BE THAWED NEAR A FIRE, but by the warmth of warm water, in some apparatus like a common glue pot, where the dynamite can be kept dry while surrounded by warm water not hotter than the wrist can bear. It is usually obtained in 2 oz. cartridges wrapped in parch- Supply, ment paper. It can be detonated by fuze and No. 8 detonator, or by Detona- fuze and cap. tion. No. 8 detonator is unnecessarily strong. When cold weather is likely, dynamite should be buried a Storage. foot or two underground. hN Dynamite Charges. 204. If a No. 8 detonator be used, this is connected up with Connecb- fuze, as described for guncotton, and the end inserted into one J^g ^^P of the cartridges for about 2 inches and tied in. ^^'^^ ^ •1 • 11 -1 itj^ix means oi If a commercial cap is used, the straight cut end oi the luze oietona- having been gently inserted into the mouth of the cap till tion. it touches the fulminate, the mouth of the cap is squeezed to hold the fuze in place. (5289) F 2 84 CHAPTER XVI.— HASTY DEMOLITIONS. The cap, with the fuze attached, is then inserted into one of the dynamite cartridges almost as far as its length, and tied into position. Arr.in2e- For a bore hole for blasting, or an auger hole in timber, as inent of many cartridges as necessary are inserted, and each squeezed cimrge. -^^ separately with a wooden rammer {see Fig. 7, PI. 68). Iron Boreholes, must not be used to ram with, and the ramming should be gently done. The cartridge with detonator or cap for firing should be the last, ri icing For other charges the dynamite should be tied up in as .thiirges. compact a parcel as possible, and placed tight against the object, the means of detonation being in one cartridge. All the cartridges of a charge must be in contact. Hole for Holes for detonators or caps must be made with the rectifier f-^P- or a piece of wood. 'lamping. The tamping of a bore hole may be sand, clay, or water, but in the latter case the cap must be kept dry. Ciiccldite. A new explosive called cheddite is coming into use; it has about the same explosive effect as dynamite, and has the advantage of not freezing at so high a temperature. It would be useful in blasting work. Use under For use under water dynamite and similar explosives should uater. \jq ^ied in a waterproof bag {see PI. 68, Fig. 8) . Means of Detonation and Ignition. Detonators. Dctoua- 205. There are two kinds of detonators in the service for tors for detonating guncotton ; only one will be here described, gunootton, y^^., that called " Detonator No. 8 for safety fuze " ; the other, which requires electrical firing apparatus, being beyond the scope of this manual. Iso. 3 Fig. 1, PI. 68, gives a section of this detonator. It consists dcionalor. ^f ^ brass tube painted red, the small end of which, A, contains PlCLte f'8 HASTY DEMOLITIONS Irq. J. 0Ti-Lrky^)lLCfj"7t Ft^ 9. ■Jbi ^^•7' s/ee. 4,05. Sot/et^' fiae^s^J TrkjfLe Commfn^rJ /fT C/tp ?oz d^y disc^ Tz^.S, 7r (pr'im.eif^j ^W .6. ^^ 7oz 7>rii SFi^.S. weiiera.GfiMtam.Lr!' urhoxenden. Opposite pct^if S4 CHAPTER XVI. — HASTY DEMOLITIOMS 85 t"he detonating compound (fulminate of mercury) ; above this is a wooden plug with a hole in it, through which passes a piece of quickmatch. The upper end of the tube is empty, for the insertion of the fuze, and is closed by a small paper cap. These detonators are packed in tin sealed cylinders painted red, which contain 25. A new pattern No. 8, with a short shank, will shortly be introduced. No. 8 detonator will detonate dry guncotton, but it will not detonate wet guncotton or cordite without a primer. Both safety and instantaneous fuze can be connected to it. Where dynamite is obtained a smaller kind of detonator Com- used in civil works will often be available and should be used in mei-ciai preference to No 8 detonators as being more economical. *^''^'^^^ This is the " commercial cap," which is made of copper, and contains less fulminate than the No. 8 service detonator, see Fig. 9, PI. 68. These caps vary slightly in size and strength. To detonate- dynamite, trebles are used as a rule. The weaker sorts cannot be counted on to detonate guncotton primers, but "sextuples" are strong enough. They can be connected up to safety or instantaneous fuze. Detonators must be stored apart from explosives ; when Storage- attack is likely they should be protected from bullets. Fuzes. 206. The present pattern of safety fuze is known as " Safety, Safety No. 9." i"2s- This consists of a train of fine gunpowder enclosed in jute yarn, covered with guttapercha and waterproof tape. It is packed in tin cylinders containing 8, 24, or 50 fathoms. It is coloured black. Safety fuze will burn under water. Bnmin^ under water. 86 CHAPTER XVT. — HASTY DEMOLITIONS. Bate of For practical work the rate of burning can be taken as 3 to burning. 4 feet per minute. Old fuze. Old fuze should have its rate of burning tested before being used. Fuze which has been more than six months or so in a tropical climate should be very carefully examined. Lighting It is difficult to light safety fuze with a match or flame. A portfire or vesu\'ian (fusee) is best, but in the absence of such means of ignition,, the head of a match inserted in the fuze and lit by another match, forms a good method of lighting. A glowing cigar, cigarette or pipe is also good for the purpose. Instantaneous Fuze. Instanta- 207. Consists of two strands of quick match enclosed in flax neous and several layers of guttapercha and waterproof tape, fuze. j^ burns at the rate of 30 yards a second, or practically in- stantaneously ; it is packed in sealed tins holding 100 yards. It is coloured orange. It can be distinguished in the dark from safety fuze by feeUng the open crossed thread snaking outside it. Joining Fuzes. Joining 208. In firing charges with instantaneous fuze, a piece of fuses. safety fuze should be joined on for hghting, in order to allow time for getting away, except in special cases where the instan- taneous fuze used is long enough to admit of being ht from a safe place. Joining To join safety and instantaneous fuze, cut the instantaneous safety and f^ze on the slant so as to expose the quickmatch for a short instanta- igng^ji ^Iso the safetv fuze in the same wav, takino; care that DCOU.S O ' • ^^ ? o fuze. the composition is well laid open. Join these two surfaces together and bind up tight. A small '^' ■ piece of wood is useful as a splint, and if handy, a little powder or quickmatch can be put between the two fuzes (Fig. 2, PL 68). Joining To join two lengths of instantaneous fuze, slit the outer ^^° covering of each piece of instantaneous fuze at the end, it if"? t ^^^ ^^^^ ^^ turned to expose the quickmatch ; the strands are neous then twisted together, the outer covering made to overlap the fuze. joint, and firmly fixed with twine. en AFTER XVI. — HASTY DEMOLITIONS. 87 Joints in fuze can be made waterproof by wrapping them Water- round tight with indiarubber tape smeared with indiarubber pf'^ofing solution, which aro articles of K.E. equipment. Ordinary ■'^"^ ^' tape and tallow would do for a short time against damp. Simultaneous Charges. 209. Charges are best fired simultaneously by electricity. Simulta- When this is not available, it may be done as shown in Fig. 3, ^^"^ PL 68, by using equal lengths of instantaneous fuze, " 6c," '° which are ignited at " 6 " by a length of safety fuze, "a?>." The joint at " b " can be made with a small bag or box of gunpowder, into which the end of the piece of safety fuze and the ends of the instantaneous fuze are led, the quick- match in the latter being exposed. Care must be taken that the lengths of instantaneous fuze are equxil, irrespective of the distance from the powder box to the charges. Substitutes for Service Fuzes. 210. When service fuzes are not available, means of firmg must be improvised. " Mealed powder " (which is very fine), moistened, or ordinary Mealed gunpowder ground into a fine paste with water between two powder, pieces of wood, can be pressed into a tube and used instead of safety fuze. Tliis burns at the rate of 2 feet per minute, or slower, depend- ing on the dampness of the powder. Powder hose, made up by filling tubes of strong linen Powder with fine powder, can be used instead of instantaneous fuze, ^^o^^- The tubes can be from -J inch to 1 inch in diameter, made from one strip of stuff ; they are loaded in lengths up to 20 feet through a funnel. The lengths can afterwards be joined. It burns at the rate of from 10 feet to 20 feet per second. Precautions. 211. For amount of explosive required, see Chapter XXI. General For cordite and dynamite use slightly more than is required ^^^^' for guncotton. 88 CHAPTER XVI. — HASTY DEMOLITIONS. Storage of (letonators iu cam}3. Connect- ing up detona- tors. Connect- ing up caps. ' Protec- tion to detona- tor for lamping. When possible, tamp all charges. If guncotton charges are tamped, one-half the charges given in the table are sufficient. For demohtions in the presence of the enemy, increase the calculated charges by 50 per cent. Detonators should be buried to prevent being exploded by stray bullets. When connecting up No. 8 detonators with fuze, the de- tonating ends of the fuze should not be pointed at anybody. When carried out under fire, take every precaution against a possible failure ; detail spare men to carry the stores to replace casualties, and see that every man with the party has tl'^^ mean." of lighting the charge. For large charges of all sorts which cannot easily be got at after tamping, and for demolition work where certainty and rapidity are essential, it is a good rule to insert two fuzes (and detonators if required) in the charge in case one should prove^ faulty. When pinching or bending the mouth of a detonator or cap to grip the fuze, care should be taken not to squeeze the detonating end. When tamping a guncotton charge with earth, stones, &c.,, the detonator should be protected from being knocked. Make arrangements to prevent sparks from the fuze causing premature explosion of gunpowder charges, or setting fire to guncotton. Brickwork and Masonry. General. 212. For the demolition of brickwork or masonry with gun- cotton, the charges worked out by the formulae in the table- will sometimes be too small to allow the whole length of th& breach to be cut, being covered with whole slabs touching each, other. In such a case : — (a) If guncotton is available, do not divide slabs, but add extra slabs till the whole length to be cut is covered by slabs touching each other. (6) If plenty of guncotton is not available, cut some of the slabs so as to make the charge stretch right across. Smaller pieces than thirds of slabs should not be used. PlaU^ 69. Ttq.3. PREPARING CHARGES Tx^.4-: ^^■o. ^o^vd&r -4 14 'i^ ^ MB / 5^ no/ hag holds about 50 lbs of Gunpotvder. We»llat^ IL GIRDER BRIDGES VrT\ I I I Wedged J^osztioTLr o/" CTiccnaes 21X, ope Clip JfooderL riifu GirdLer' -itztA plate. -^^. •pT'znczpZe- sTvcnvrLhy ciott&d^ Fi^.^. Ti^6 CTtaarffe-TrL FToTLof ytrdeT^ S/8€. 8 % < ins. ft. ft. lbs. lbs. £ Heager 170 38-5 4-52 9-33 252 1,736 "5 butt 108 33-3 3-97 8-09 174 1,125 t puncheon 72 30-7 3-20 7-57 140 773 « hogshead 54 28*6 2-76 7-05 119 .'i67 5- barrel 36 25-3 2-42 6-23 88 382 half hogshead 2G 22*7 2-12 5-61 65 269 rg kilderkin 18 20-3 1-81 5-02 49 185 « small cask 14 18-3 1-76 4-49 32 146 '^ l „ 6 13-8 1 -37 3-40 20 60 I'owder f whole barrel barrels \ quarter ,, IT -5 1-58 4-26 28-5 115 — 14 1-17 2 '93 8-5 39 fton Commissariat i 5 ton — 40 3-2 9-96 95 1,477 — 32 3-2 8*69 74 1,134 vats 1 —ton — 31 3-3 7-75 67 903 Ls-lon 27 2-5 6-61 51 499 Water cask — — — — — 60 106 CHAPTER XVIII. — STRENGTH OF MATERIALS, ETC. Buoyancy 271. The buoyancy of a log can be obtained by multiplying ^ ^^ ^^' its cubic content by the difference between its weight per cubic foot and that of a cubic foot of water, viz., 62| lbs. The actual flotation then of the log given below, if it were pine, would be : — 95 X (62J - 40) or 95 X 22^" = 2,137i lbs. As, however, timber absorbs a great deal of water, only | of the above can be safely relied upon. This available buoyancy will then be — I X 2J37| = 1,781 lbs. 272. The contents in cubic feet of an unsquared log of timber can be found by the following rule : — L ^ (D- + Dd + d-). Where L = length of log- in feet, D, d = diameter at ends. Thus, if the log- is 3 feet and 2 feet in diameter at the ends and 20 feet Ion or — Bridges of rafts of timber. the cubic contents = 20 95 c.f. W^eightof 273. The follow ving are approximately the w imber. foot of different kinds of timber :— Ash, English .. 46 lbs. Pine .. Beech . . .. 43 „ Poplar Chestnut .. 41 „ Sycamore Elm ., 37 ,, Teak, Indian Fir .. 33 ,. „ African Larch . . .. 33 „ Yew .. Maple . . .. 32 „ Walnut Oak, English . . 57 „ Blue Gum Willow . . . . 25 lbs. 40 lbs. 36 51 61 41 38 63 M J'late 73. Opposi te. jjcLtye 70. 107 CHAPTER XIX.— BLOCKS AND TACKLES— USE OF SPARS. 274. Blocks are used for the purpose of changing the direction Blocks of ropes or of gaining power. and They are called single, double, treble, &c., according to the tac'des. number of sheaves, which are of metal or hard wood, and revolve on the pin, which should be kept well lubricated. Snatch blocks, Fig. 1, PI. 73, are single blocks with an opening in the shell and strap on one side, to admit a rope without passing its end through. The rope with which tackles are rove is called a fall. To overhaul is to separate the blocks. To round in is to bring them closer together. When brought together the blocks are said to be chock. 275. A tackle is rove by two men, back to back, 6 feet apart ; KecTing. the blocks should be on their sides between the men's feet, hooks to their fronts, and the coil of rope to the right of the block at which there are to be the greater number of returns. Beginning with the lowest sheaf of this block, the end of the fall which is to be the standing end is passed successively through the sheaves from right to left and then made fast. 276. In using tackle great care must be taken to prevent the Pre. tackle from twisting. The best method is to place a handspike cautions between the returns, close to the movable block, with a rope ^^^^■^ to each end, by means of which it can be steadied. New rope must be uncoiled and stretched before using it as a " fall." Crane chain, when used as a fall, should be thoroughly Crane soaked in oil. cliain. 277. Various tackles are sho\sTi in PI. 73. The power Power. necessary to raise a weight W is W -f- number of returns at the movable block -f- about 10 per cent, per sheaf for friction. 278. The fall, in lifting heavy weights, can rarely be worked Machines, by hand, but has to be " led " to either a capstan or winch, by which power is gained and a steady pull ensured. 108 CHAPTER XIX. — BLOCKS AND TACKLES, ETC. Carrying 279. In carrying spars, the party should be equally divided spars. on either side of the spars, facing it, and sized from one end. The spar should then be lifted, in two motions, on to the inner shoulders, the party facing one way. In lowering a spar, the party should slowly face inw^ards, and lower the butt end first to the ground, and afterwards the tip. Derricks. 280. A derrick (Fig. G, PI. 48) is a single spar set up with four guys, secured with clove hitches. A tackle is lashed to the head, and the derrick can be used for raising and swinging a w^eight into any position within its reach, which is about one-fifth of its height. The anchorages for the guys should be at a distance from the foot of the derrick equal to twice its height. The foot should be let into a hole in the ground to prevent its slipping. In Fig. 6, PI. 74, a derrick is shown in the act of raising a pair of sheers. Fig. 8 show^s a swinging derrick. Sheers. 281. Sheers (Fig. 4) require only two guys— a " fore " and " back " guy. They should be fastened to the legs above the crutch by clove hitches, the back guy to the fore spar, and vice versa, so that their action may tend to draw^ the spars closer together and not strain the lashing. The minimum distance of the anchorages should be double the height. The upper block of the tackle is hooked to a sling of rope or chain passed over the crutch. Sheers can, as a rule, be used for heavier weights than derricks, but can only move them in a vertical plane passing between the legs. The feet of sheers must be secured or let into holes in the ground. The distance apart of the legs should not be more than one-third the length of the leg up to the crutch, and the sheers not to be heeled over more than one-fifth of their height. Sheer 282. The legs of the sheers are laid side by side on a skid, and lashing. j-ept 2 inches apart by a wedge. The lashing is commenced with a clove hitch on one spar, carried six or more times upwards round both spars without riding, then tw^o Trapping turns, and finished off w^ith two half hitches round the other spar. (Figs. 1 and 2, PI. 74.) I*lcOte '74 Fi^.L USE OF SPARS jtiq.Z. Fry. 3 STveei^s ybte. . JBiflFiff. S. fyctf^pTiriff turns ar^ cT/oMed' so us to s?to\^ WellerAGratwm.LH Litho.LofxJon. CHAPTER XX. — FRAME BRIDGES, ETC. 100 283. Gyns, Fig. 5, require no guys, and are good for a Gyns. vertical lift, such as dismounting gans. The three legs of the gyn are placed as shown in Fig. 3, resting on a skid, and 2 inches apart. The lashing is com- menced with a clove hitch on an outside spar, and carried upwards over and under loosely and without riding six times. Two frapping turns are taken in each interval, and the whole finished off with two half hitches round one of the spars. Iron chain is better than rope for these lashings, as it admits of fewer turns, which allows the legs to be more easily opened. 284. In using tackles with sheers, gyns, or derricks, the Leading running end of the fall should always be led through a " leading blocks, block," lashed, as a rule, to one of the spars a few feet above the ground ; a snatch block is most convenient for the purpose. (Fig. 7, PI. 74.) CHAPTEK XX. — CANTILEVER BRIDGES, FRAME BRIDGES, FRAMED TRESTLES, SUSPENSION BRIDGES, AND CASK PIERS. 285. Pis. 75 and 7G show various types of cantilever Cantilever bridges as used in Northern India. bridges. From the smallest to Ihe largest span the method of con- struction is practically identical. A site is chosen where a large rock or rocks rise out of the stream or a pier is con- structed of dry stone work and wooden bindings. On the top of tliese are laid a number of stout beams, ««, projecting over the stream, with the projecting end somewhat higher than the shore-ends. The number of beams, their length and amount of projection depend on the span. The shore-ends of each row of cantilevers should be covered with planks or like material. Stones are then packed round these ends, and the v/hole weighted down. It is also desirable to lash the top iayers to the bottom ones as shown in Figs. 5 and G. no CHAPTER XX. — FRAME BRIDGES, ETC. Frame bridges. Single- lock bridge. Double- lock br.due. Supposin^!^ that the central span is too lar.i^e for available timbers, then more rows of cantilevers are placed on the first row aa, two more transoms tt are placed near the projecting" ends and the roadbearers rr are placed in position. There are n. LOCK BRIDGES. a. road boarers, b.fork tranaoai. c. frame transom. d. shore transom. e„ legs. f. djAgonal bra(»3 SINGLE LOCK. g. ledger. "• footings. i. anchorage for f potropes . J. chesses, k. ribands. a. read bearer. b. road transom. c. frame transom. d. shore transom, legs. f . diagonal braces g. ledger. n. footings, i. footropes^ j, chesses. ribands . distance pieces Note J Pootrofes are removecT after franies are locked. ■iiec 9 05 WdlerAGraham. Lri* UHio.London. To f'olZcw Ptoute 76. CHAPTER XX. — FRAME BRIDGES, ETC. Ill lowered, and if a single-lock bridge, locked ; if a double-lock bridge, held back by the guys a little higher than their ultimate position. A single-lock bridg'e is then completed with the usual roadway : for a double-lock bridge two ^ distance pieces must be placed across the ends of the frame transoms, as shown in the diagram and the road-bearing transoms lashed across, as shown. The back gu^'s can now be eased, and the bridge allowed to lock. The roadway is completed as usual. In order that the parts of frame bridges may fit together, considerable accuracy is necessary in taking the measure- ments and marking the positions for the lashings. To this end a section of the gap and proposed bridge should be marked out on the ground, allowing for camber. The spars for the legs must now be laid on this section in the exact positions they will occupy when in bridge, and marked to show proper positions for lashing on ledgers and transoms. 289. The following approximate dimensions of timbers for Dimen- single and double lock bridges are necessary for carrying ^1*^"^ °^ infantry in fours crowded : — Legs . . 7 inches at tip. Frame transoms, mean diameter . . 6 inches. Distance pieces ,, ,, .. 11 inches. Other spars as for trestle bridges. 290. Plates 78, 79 and 80 show examples of heavy trestles Framed made of timbers framed together and fastened by iron dogs, t^^^^^^^* spikes, bolts ^ etc. They are specially useful for hasty railway bridges (see also Chap. XXIII) and for road bridges where heavy traffic is expected. Skilled labour is required for their construction. These trestles usually consist of groundsills, capsills, uprights, struts, and diagonal braces and stringers connecting the trestles in the line of the bridge. The uprights should be as far as possible arranged under the road-bearers, so as to support the weight directly. When they can be got of sufficient length, it is best to make the trestles in one tier only, however high the bridge, taking care of course that they are properly braced both ways to prevent buckling (PI. 78, Fig. 1 and PI. 79, Fig. 1). When the material is not long enough, the trestles must be ^ 112 CHAPTER XX. — FRAME BRIDGES, ETC. Struts. Bra( Corbel. Pasten- inss. made in two or more tiers. In this case the upper tiers must not be made too heavy, or they will be very difficult to hoist into position. The groundsills of the lower tier must be strong enough to support and distribute the weight of the uprights. Where the soil is firm and can be levelled to an even bed, no other foundation than the groundsill is necessary ; where the soil is soft a low crib pier may be made to distribute the weight. The adjoining capsill and groundsill, where one trestle rests on another, need not be very strong. A 3-inch plank will suffice for each, and may be spiked to the uprights. In this case the uprights may be fixed in position with cleats, and dogged to each other (PL 78, Fig. 2). 291. The inclination of the struts depend to some extent on the height, width and length of the bridge. They are not essential for wide bridges of no great height. Struts for railway bridges must have a greater inclination than for ordinary bridges to provide for wind pressure on the side of the train tending to overturn the whole structure. This is especially the case when the bridge is high and long. 292. For the arrangement of the diagonal bracing, see Plates 78 and 79. The ends of struts should not be notched into uprights unless the latter have a considerable margin of strength and stiffness. Uprights and struts should be notched into groundsills and capsills when possible ; but when time presses and few car- penters are available, a careful arrangement of dogs will suffice, without notching. 293. PI. 78, Fig. 4, shows a corbel, an arrangement for giving a wider bearing at the top of a trestle ; and Fig. 5 an alternative method, which also helps to fix the capsill. 294. Dogs, spikes and bolts are the most useful fastenings for framed trestles. The position of each dog should always be considered with a definite object of preventing a possible distortion of the frame. They should be on both sides of the trestle. Dogs should not be driven within 3 inches of the edge of a timber, or within 4 inches of its end. Spikes, when used in pairs, should be driven inchning towards each other. They run 5 inches to 10 inches in length. J>laJbe78 Fig1 rRAMED TRESTLE Squared Timber f-^'SX-A Tt^ 2 7\ Fi^ 3 Jl wrong position^ for dog. Fj^,^ Fvg 6 ^ .a ^ n;^ a a Composite roadhearers wittcplxviks fhreaJujiq Joint ■Welleri Graham L!f Lirtw. London C)j)posvte page J^-^ ricute 79 FRAMED TRESTLES Sleep y j.,se'.^ Fistcp 5 coaxifv scTt Tresile with. \' ilsTv phite g-^^^ rastemn^s t boU Vf'drvri%oUs ''^gdrU'-ii'olts ''/a'^drift l>oUs -^M ' m^ FICLTV Trestle of Flouaks CapsilL ^ ^J-ron stiiap. Wel!er46raham.l'* Liffto, London. JhfoUxfyy pZate 78: PlcLte SO FRAMED TRESTLE Round Timbers "''' "" ~" •*" ' •''T^rfiiTr-ff^r4r;7-;;iri7r Fi(j. 2 ELe\'aJLiorv To follj^-^;e>i J^z^.S. Weller 4 Graham. W LithaLonaon. Opposite' poLg^ J24-. Plat^SZ TEMPORARY ROADS Tis^.7. ff # j^ .<^ '-.„^r --^" '_f gug^gdilg^M i he m • ^^^,.^^i%l / JFl^.Z. ^ / s. 6talt orvJFcLSctrves. '^-^^- f8 0'- -tf'd \ 1^^ 1 iJ'."J ^^^JO^^i^'Tj 1 ' 1^'"^ ijL<.U,,jJt^.. 'w^n I^^j^ffl^wjy ^ jPF?^^:^^^ iwft, ._, •••-■*T^' ■ '- * siasB OS. Welter 4 Gp«h»m.L>^ Litha London. TofoUxrw plccUSi CHAPTER XXII. — ROADS — BONING AND LEVELLING. 125 again as in the straight portions. Short zig-zags should he avoided. 308. When a road passes over verv wet or marshy ground, and 'Roa^s brushwood is available, it should be made up into fascines across or hurdles, or even laid loose across the road (though this ^^^^^nes. plan is not so good as if made up) as foundation for the road material. 309. When fascines are used there may be one, two, or more Fascine layers (Fig. 3, PI. 82), according to the requirements of the ^^o^^- case, the top row being always at right angles to the direction of the road. 310. With hurdles their length should be equal to the width Hurdles, of the road, and there should not be less than two layers across the road, the layers breaking joint. When the road is a permanent one it is considered ad- visable to place the brushwood at such a depth below the surface as will ensure it always being damp, as when it is alternately wet and dry it soon rots. Four inches to six inches of broken stone or gravel are then laid on top, or, if these materials be not available, the earth excavated from the trenches on either side is thrown there, the surface being sloped as already described. 311. The trenches should be cut about 3 feet or 4 feet from Trenches, the brushwood on either side, and outlets should be made from them at intervals, to allow the water to discharge into lower ground. 312. See Chapter XII. Corduroy road«. 313. Eoads which are exposed to the traffic of heavy military Repair of vehicles require constant repair. Parties of men under a ^°^^^* N.C.O. should therefore be told olf to every 3 or 4 miles of road to keep it in order, and depots for road metaUing should be formed at short intervals from which the material is dis- tributed along the road as required. The material used may be either broken stone (of a size to pass through a 1 J-inch ring), broken furnace slag, brick or gravel, which should be apphed in thin layers, the surface of the road being first loosened by scoring it with, the pick. Tools. — Shovels, picks, rammers, measuring rods, levels, Tods. &c. ; also, to break up the metalling, stone hammers 3 lbs. 126 CHAPTER XXII. — ROADS — BONING AND LEVELLING. in weight, with handles 2J feet long, so as to work standing, or of H lbs. weight, with handles 18 inches to 2 feet long, to work sitting. Boning and Levelling. Levelling by means of Boning Rods. Definition. 314. It is often necessary in the field to make a rough section of a piece of ground or parapet, so as to calculate the amount of work to be carried out, or to lay out short lengths of ground at a given slope, as in road-making, drainage, &c. For such purposes levelling by means of boning rods may be employed. Tools. 315. The tools required for boning are a field level (or a mason's level, or a spirit level with a straightedge), a mallet, pickets, measuring tape, a set of three boning rods, and where great differences of level are met with, a long rod graduated to read feet and inches. Mason's The mason's level is sho\\Ti in Fig. 1, PI. 83, and can be made level. by any ordinary carpenter, where a field level is not available. Boninc Boning rods are usually made of deal, 3 inches wide and rods. I inch thick, and consist each of a long arm, with a head dovetailed on at right angles to it (Fig. 2, PL 83). Care must be taken that all of a set are of exactly the same length. 316. To make a section with such rods, it is usual to select the highest point of the section and there drive in a picket flush with the ground, driving in a second picket on the line of the section with its top carefully levelled to the top of the first picket (by means of the field, mason's, or spirit level), and as far away from the first picket as the length of the level or straightedge \\dll allow {see A, B, Fig. 3, PL 83). It is evident then by look- ing over the tops of the two pickets (A, B), the depth below the line of sight of any other points (C, D), on the section could be determined by holding up a measuring rod at those points, and the horizontal distance apart of the various points being also measured, a rough section could be made. To avoid the obvious difficulty of getting one's eye down to the top of the first two pickets (A, B), boning rods are set up on them, and a third boning rod (or the long rod) is set up at the different :Plcxjtie< (S3 BONING & LEVELLING -Z^.^. ^ s JFigr. -e — -i^ ;' TO — i i.l '^MWa -t jj ?jj ^^^/^ •ir ,Sj)irvbjLeyel -^^MT :Fi^.5. "%W; H^kt, ang^fes to t^.ev^pTy)pej^ positiok 5186 l. OS. Wcl!er& Graham. L<:'? Litho. London. Oppos tte pa^e J2G. M4xte^84. Field Level Fi^.l. ^-ji--i^;mr-- iimi. •cfciCd*^ Jz^.Z. <-e9Si.9.as. Pl^e-SS. Field Level fcont^) /CS tb CL/ ^oot>. Fi^.4^. '^ J^e^^eZy foZd^d^iap -%-^ JTasteirt^m^ We'erSGrdhani. w'" Lifho London TcfolUnv plyjct^ 94. ■m / *9Q€ if-ot. Plate SG tl Field Level IbfoUawplxiteSS r CHAPTER XXII. — ROADS — BONING AND LEVELLING. 127 points (C, D, E) whose level is required to be known. The boning rods being all of the same length, give by their tops a horizontal line parallel to the first line of sight, but 3 feet (or thereabouts) above It. In the same way a given slope (say y^^) can be set out (i'ig. 4) by arranging the tops of the first two pickets at the required slope (level A and B, 10 feet apart, and then cut 1 foot off B), setting up two boning rods on them, and by means of the third boning rod driving in pickets to show the top of the slope at any required points, N, 0, P. Again, a continuous slope between any two points can be laid out with pickets, as in Fig. 5, by putting the firsfc boning rod at F, the second at G, and with the third rod setting up the intermediate pickets. 317. In taking a section it is usual to enter the levels, &c., Taking in a book {see page 122). section. Field Level. 318. The field level is shown in Plates 84, 85, and 86. It can be used when closed — (1) As an ordinary spirit level for boning, levelling, &c., the spirit level being on the edge of the limb C. (Fig. 1, PI. 84.) When open — (2) As a square for setting ofE right angles. (Fig. 1.) (3) As a protractor for setting off angles. (Fig. 2.) (4) For setting off slopes of all grades, and as a mason's level with plumb bob. (Fig. 1.) In all cases place the limb A against the slope to be measured. The dotted Unes in Fig. 1 show how the instrument is closed. N.B. — One edge of the level is graduated in feet and inches. 128 CHAPTER XXIII. — RAILWAYS AND TELEGRAPHS. CHAPTER XXIII.— RAILWAYS AND TELEGRAPHS. Railways. Forma- tion. Forma- tion level. Width of railway. Gauge. 319. The duties likely to be required of troops in the field with re.^-ard to railways (apart from large railway schemes, for which special arrangements would be necessary) may be considered as either temporar}^ repairs, or the laying of short lengths of line to join up breaks, the construction of addi- tional works such as platforms, &c., to adapt the line for military use, or the demolition of an existing line. 320. The formation includes the whole of the earthwork necessary to complete the line to "formation level" and secure the required width of way together with "side" and " catchwater " drains, and any " retaining walls" or protective works to secure the bank against floods. Tuimels are included under the head " Formation." 321. Formation level means the level of the completed surface before the ballast is put on. On rapidly constructed military lines, where ballast is possibly not available, the formation level would be the depth of the rail and sleeper below the rail level. The formation level is not absolutely horizontal transversely, as it should slope slightly downwards from the centre line towards the sides of the bank or cutting for purposes of drainage. 322. The width of the railroad depends on the gauge, the width of the rails, the clear space outside the rails and the space necessary for drainage. ' 323. The gauge is the shortest distance between the inside edges of the upper surfaces of the rails, and is | to 1 inch greater than the distance between the flanges of a pair of wheels. In Great Britain, and most of the European countries, the ordinary gauge is 4 feet 8 J inches ; in Ireland, it is 5 feet 3 inches ; in Russia, 5 feet ; in British India, 5 feet 6 inches (metre, 3 feet 3| inches) and 2 feet 6 inches. For a 4-feet 8j-inch gauge, single hne, the minimum width of banks and of cuttings at formation level should not be less than 12 feet and 16 feet respectively. These dimensions CHAPTER XXIII. — RAILWAYS AND TELEGRAPHS. 129 might be taken for gauges of 3 feet 6 inches, or metre gauge (3 feet 3| inches). For a 2-feet 6-inch gauge these miuimuni dimensions might be reduced by 2 feet. For every additional line of rail it is necessary to add the gauge plus two rail- heads, plus a way between the tracks such that two vehicles can clear each other witli their doors open and a little to spare — say 11 feet for the 4-feet 8j-inch gauge. 324. General type of first-class English railwa}': — Perma- i?«/Z5.— Steel double- headed, weight 80 to 90 lbs. per '^^^^ way. yard. Sleepers. — Balric fir, 9 feet by 10 inches by 5 inches (PI. 87, Fig. 2), weight 140 lbs. ; laid 3 feet apart centre to centre, 2 feet 2 inches at rail joints. Chairs, — Cast-iron ; width 6 inches or 8 inches ; weight 45 lbs. each ; secured by two steel spikes and two screws. (Fig\ 4.) Keys, — Compressed oak, 6 inches long. (Fig. 4.) Fishplates. — Steel ; weigJit 54 lbs. per pair ; secured by four steel bolts | inch diameter. (Fig. 7.) Ballast. — Screened cinders, broken granite or slag, size not exceeding 1^ inches cube, nor more than 10 per cent, to pass -^-inch mesh. Rounded gravel, if used, to be mixed with sand or broken stone to prevent it from working out from under sleepers. In most foreign countries, however, the flatjooted or Vignoles rail is used. This does not need chairs, and is spiked direct to the sleepers, sometimes with a bearing-plate between if the timber is of a soft description. 325. Two of the many different kinds of rails in use are shown EaiK on Plate 87, Figs. 5 and 6, the double-headed and the flat- bottomed rails are usually made in lengths of from 15 to 30 feet, or even 60 feet, and weigh up to 110 lbs. per yard for permanent lines intended for heavy traffic. 326. The rails are connected together by two fishplates of Rail wrought iron or steel, each with four bolts with nuts and joints. washers. The sleepers on each side of the joint are brought closer together so as to reduce the bearing to about 2 feet. (5289) I 130 CHAPTER XXIII. — RAILWAYS AND TELEGRAPHS. Sleepers. Ch lies. Connec- tion between chairs and sleepers. Connec- tion of rails with chairs. Connec- tion between rails and sleepers. Ballast 327. Sleepers are bearers, whether of wood or of steel, used to distribute the weig-ht on the rails over the ballast or roadway, aud in the case of cross-sleepers as a connection between the two rails to preserve the g"auge. Each mile of railway requires 1,850 to 2,000 sleepers. 328. Chairs are used to connect the rails to the sleepers, when necessary owing- to the sectional form of the rail, and to distribute the weig-ht over a greater bearing area on the sleeper than is obtained by the rail resting on it. 329. Chairs are fastened down to sleepers by spikes and treuails. Trenails are wooden spikes, so compressed by machinery as to expel all moisture from them. When they have beea driven into the sleepers their tendency is to absorb moisture and swell, and so to grip the sleeper more tightly. They must not be employed alone, but where they are used there should be at least one iron fastening to each chair, for, although the trenail is a firm means of holding down the chair to the sleeper, it is liable to rupture from a shearing stress. For this reason, oak trenails with iron spikes driven into them (PI. 87, Fig. 3) are often used. In the case of flat-footed rails with good bearing area aud exposed to moderate axle loads, the rails may be spiked direct to the sleepers without chairs or bearing -plates. 330. The double-headed ;md also the bull-headed rail is held in its chair by a key or small block of wood, compressed b}' machinery (Fig, 4). This key is slightly wedge-shaped, and is driven firmly into the gap in the chair at the side of the rail. Rails may be ke3'ed on the outside or inside. 331. Flat-footed rails are generally connected directly with the sleepers by dog-spikes, or with the interveutiou of hearivg-plates. 332. Ballast is broken scone or other suitable material placed on the formation level, on which the sleepers rest, and with which they are " packed " to the proper level or inclination. The objects of ballast are: — i. To distribute the pressure imparted to it by the sleepers over a larger area. PZoJUSl RAILWAYS >Y7. Sr—Z^. O^. FzQ.3 Flge. 13^' - ried^ J^.7 ^S^ StSS.9M»Sm Weller I. Graham. U?' Utfco. London. Opposite pcLff» /^^( P7, strength of cordage 101 Earth, slope of . . . 17 „ suspension bridges IIS Earthworks . 31 „ velocity of stream 56 Embankments . 27 Fortification, object of . . . . 5 Entanglements, tree 42 ,, principles of . . 5 „ wire 42 Fougasse 43,138 Entrances to redoubts .40,48 Fcur-legged trestles . . . . 61 Epaulments 37, 138 I'raises . . . . . , . . 43 Execution of work . 14 Frame bridges no Explosives carried in the field . .13,78 Fuzes 85,86 „ substitutes for . . . . 87 Fascines . . 19, 23, 51, 120, 1 25, 138 Gabions 20, 23, 138 Faults in telegraph line . . . 99 „ Jones' . . . . . . 22 Ferries . 66 Garrison of redoubts . . . . 39 Field geometry 10 Gauge of railways . . . . . . 128 „ guns . . . . 7, 58, 95, 102, 119 Geometry, field . . . . . . 10 „ howitzers .8,102 Glossary of terms 137 „ kitchens . 68 Guncotton . . . . . . . . 79 „ level . 127 charges .. 80,119 ,, ovens . 69 Guns, destruction of . . 95, 119 „ redoubts . 38 „ field . . . . 7, 58, 95, 102, 119 Filtration . 72 „ siege . . . . 8, 58, 95, 102, 119 Fire, artillery 7,8,9 >, spring 47 „ natures of . . 9 Guys . . . . 108, 109, 138 „ rifle . 6,9 Gyns 109,138 „ trenches . 33 Fishplates . . . 129 Hasty demolitions, formula for 118, 119 Flares . 47 ,, „ with explosives 78 Floating bridges . . . 62 „ „ without explo- Flying bridges . 66 sives . . 93 Fords . 67 Head cover . . . . . . 34 Foreground, clearing the. . 25 Hedges 25,27 „ illuminati:n of . 47 Height of line of fire . . . . 6 Forming cuts . 66 Houses, demolition of . . . . 90 » up 65 Howitzers, field .. .. ..8,102 142 INDEX. PAGE PAGE Hurdles . . 22, 23, 74, 75, 120. 125 Penetration of artillery projectiles 7 Huts . .75, 77 rife bullets 7 „ demolition of .. 90 Pickets 20 Illumination ..44,47 Platforms, temporary Poles telegraph .. . 132 . 134 Insulators . . .. 134 Posts, defence cf . . 44 Intrenching tools . . ..12,13 Powder 81 Inundations 44 „ charges 31, 118 Invisibility . . ..32,39 hose 87 Jones' gabions .. 22 „ mealed Power of tackles . . . 87 . 107 Kettles, service ..66,68 Precautions with explcsvcs . 87 Keys .. 129 Primers 79,80 Knots .. 52 Principles of fortification 5 Profiling . . . 15 Lashings . . . . . . 5 4, 108, 110 Proof thickness of materials 7 rack .. 53 Protected look-out . 36 Latrines ..40.69 Pumps . 72 Level, field . . 127 Purifying water . . . . ,_, 72 Levelling . . .. 126 Line of fire, height of 6 Rack lashing . 53 Localities, defence of 44 Rafting . 66 Log breastworks . . 28 Rafts 64, 66 Log huts 77 Rails, destruction cf . . 94 119 Lookout, protected 36 „ types of 129 Loopholes . . . . 2Q 30, 34, 48 Railwa;/ bridges . . 132 „ „ demoHtioa ot , 93 Makeshift, anchors 65 Railways 93, 128 Materials 17 „ demolition of . . 93, 96. 119 „ proof thickness of 7 „ repair of 131 Mats, straw 77 Randing 22 Mechanical alarms Mousing .. 47 .. 55 Ranges of various weapons Rectifiers ,. 8 81 Redoubts . . 31,38 Netting, wire Night attacks 24 .. 49 „ high command . . „ low command . . 39 39 Object of fortification 5 Rehef 139 Obstacles ..41,49 Revetments 23 „ passage of .. 44 Rifle fire 6,9 Outposts, cover for .. 49 „ rests fixed . . 47 Ovens, field .. 69 Roads 123 Overhead cover . . .. 35 „ corduroy . . 52 „ gradients of 123 Pairing .. 21 „ lajdng out 123 Palisades . . 43 „ metalled . . 124 Panels, straw 77 >. repair of . , 15^5 Parties, working . . 14 „ temporary 51 rNDEX. 143' PAGE lAOE Sandbags . . . 28, 35, 120 Telegraphs, destruction of . . 98, 119 Sangars 40 Telephones . . .. 133 Savage warfare .. 46 Temporary communications 51 Screens .. 30 Terms, glossary of .. 137 Seizing 55 Thatching .. 76 Service kettles ..66,68 Thickness, proof of materials 7 Sewing .. 21 Timber, buoyancy .. 106 Siieers 108, 139 „ destruction of . . .. 91 Simultaneous charges .. 87 „ felling .. 18 Single-lock bridge . . .. 110 „ revetment 24 Sinking wells .. 71 „ weight of .. 106 Siting of redoubts. . 39 Tools, cutting 13, 120 „ trenches 31 „ double-manning . . .. 16 Sleepers . . 130 „ intrenching.. . . 12, 13 Slewing .. 22 „ use of .. 12 Slinging; ca«ks .. 53 Trace of redoubt . . 38 Slopes, description of 10 Traverses . . ..36,40 Sods 17, 24, 120 Tree entanglements .. 42 Spars . . 59, 103, 107, 108, HI Trenails .. 130 Spifclocking . . .. 123 Trenches . . .. 31 Sphnter proofs 36, 40, 139 „ communication .. 37 Springs ..71,72 „ cover .. 37 Stations, railway, defence cf . . 46 „ drainage of ..37,40 Stays and struts . . .. 135 jj nre 33 Stockades . . . . 29, 92 „ siting 31 Stones, parapets of .. 17 Trestle bridges .. 59 Straw panels .. 77 „ fourlegged . . .. 61 ;, mats 77 „ tripod .. 60 Stream, average yield of . .. 70 Tunnels, demolition of . . 95 „ measurement of b •eadth H „ velocity . . .. 56 Use of spars .. 107 Strength of bridges 58, 102, 111 „ tools 12 „ chain . . .. 102 „ cordage .. 101 Velocity of stream .. 56 wire .. .. lOl Villages, defence of .. 48 „ „ rope .. lOl Suspension bridges .. 113 Swuiging bridge . . .. 66 Waling .. 21 Walls, defence of . . .. 2Q Tackles 107, 139 demohtion of . . 90, 118, 119 „ power of . . .. 107 Warfare, savage . . .. 46 Tambour . . . . 139 Warping . . .. m Tamping . . 78, 84, 88 Water, filtration of .. 72 Tasks 14 „ supply .. 70 „ method of executing . . 16 ,, „ for railways . . 133 Tracing .. 15 „ weight of . . 70, ].04 Telegraphs 98, 133 Wattle and daub . . .. 77 144 INDEX. PAGE T.\C,K Weapons, rano:es of 8 Wire rope, strength of , . . . 101 Wells ..71,72 Wires, earth .. 134 Willesden canvas . . .. 24 Withes 19 paper .. .. 22 Woofls, defence of .. 28 Winch .. 107 Working party tabic . . 120 Wire entanglements .. 42 „ „ detail of . . .. 136a „ netting .. 24 „ parties, detailing ^ 14 (Wt. 11464 35,000 9 ] 05— fl & S 52S9) P. 04 1027 MILITARY BOOKS, published by Autkority—contmwfiA. IiA.W. MILITARY. Manual of. 1899. Price 25. MEDICAL SERVICES. ARMY. Regulations for. 1900. Price 9(Z. MEDICAL SERVICES. ARMY. Advisory Beard for. Treatmcut of Venereal Diseases and Scabies. First Report. Price Is. 6rf. Second Eeport. 1905. Price 2s. MEDICAL CORPS. ARMY. Manual. 1904. Price 'dd. ,, EXTRACT FROM. Sec. II. DrUls and Exercises. 1903. Price :id. REO-NS. FOR ADMISSION TO. May, 1902. Price Ic/, MEDICAL CORPS AND aUEEN ALEXANDRA'S IMPERIAL MILITARY NUESING SEETICE. Standing Orders. 1903. Price l.*;. MEKOMETER. Handbook. 1904. Price 6c?. POSITION-FINDER. Handbook. 1904. 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