C8* ^ REESE LIBRARY UNIVERSITY OF CALIFORNIA. Received^ Accessions No.j?z _'--:'^^^^^^^^<'':_7c?c?_3^ e^. Shelf No.. m ^^ n REESE LIBRARY OF THE UNIVERSITY OF CALIFORNIA. Received ^9^J^!.^^^^r^_i88:Z^ .^J^Z- Shelf No. Accessions JVo.j^z^. ROYAL ENGINEER PRIZE ESSAY, 1876, THE ATTACK OF FORTRESSES THE FUTUEE. ^^ OF THE ^r \ UHIVERSITY^ CAPTAIN T. FRASER, R. E. [entered at stationers' hall.] PRINTED FOR THE ROYAL ENGINEER INSTITUTE AT THE CHISWICK TRESS. 1877. CONDITIONS OF ESSAY FOR 1876. " The Attack of Fortresses, in the future, taking into consideration the experience gained during the War of 1870-1." The Essay should contain remarks on the following points, viz. : — a. The composition of the Artillery Siege Ti-ain, with observations on the ordnance best suited for attacking fortresses. b. The composition of the Engineer Siege Train, Parks, and Depots, and the position of the latter. c. The use of wall pieces. d. Breaching by curved fire. e. The rate of fire of the guns in the Siege Batteries, and the supply of the necessary ammunition. /. Stationary Balloons. g. Observatories and telegraphic communication. h. Trench Railways. Jc. The organization and distribution of the working and covering parties. The length of the Essay should not exceed 36 pages of the Professional Papers of the Corps of Royal Engineers. LIST OF AUTHORS AND WORKS REFERRED TO IN THE ESSAY. Brialmont Burgoyne . Byland-Rheidt Ccesar Becker Boguslaushi . Taktische Folgerungen aus dem Feld- zuge, 1870-71. (Translated by Graham.) La fortification a fosses sees, 1872. Military Opinions of Sir J. F. Burgoyne. Der indirecte Schuss mit Holgescliossen. (Translated by Oliver, in the Proceedings of the R. A. Institution, Jan. 1875.) De Bello Gallico. Der indirecte Schuss vor Strassburg. (Translated by Torkington.) Geldern . . Siege de Paris et de Belfort. (French translation by Grillon and Fritsch.) Gillmore . . Engineer and Artillery Operations against the Defences of Charleston, in U.S.A. Engineer Professional Paper No. 16. Giornale d'Artilleria e Genio. Goetze, A. . Thatigkeit der deutschen ingenieur. (Vol. I., English by Graham and Martin.) (Vol. II., French by Grillon and Fritsch.) Ideen iiber Belagerungen. (Translated by Clarke for the R. A. Institute, 1872.) Les chemins de fer pendant la guerre de, 1870-71. Jalireshericlde iiber die Veranderungen und Fortschritte im Militairwesens. Sieges in Spain; by Sir J. T. Counterpoise Carriages and Platforms. (Washington, 1869.) Ho h enlo h e- Ing el- fngen . Jacqmin, F. Jones Josephus . King, W. B. IV LIST OF AUTHORS, ETC., REFERRED TO. Lagrange . . Essai historique sur les Mines Militaires anciennes et moderues. Livy . . Historiae. Militair Wochenblatt. Minutes of Proceedings of the Royal Artillery Institution. (M.P. R.A.I.) Mittheilungen liber Gegenstande des Artillerie uud Genie- Wesens. . Die Entwickelung der Preuszisclien Fes- tungs und Belagerungs — Artillerie. (Part IV. Translated in the Intelli- gence Branch.) Siege de Sebastopol. . A Course of Elementary Fortification, by Sir C. W. Die Cernirung von Metz, 1870. Historia. Professional Papers of the Corps of Royal Engineers. (P. P. R. E.) Revue d' Artillerie. Saxe (Marshal) Memoir on the Art of War ; extract in Valancey^s essay on fortification. Sebastopol . Journal of the Operations conducted by the Corps of Royal Engineers. Tiedemanii . Der Festung's-Krieg, 1870-71. (Translated by Tyler.) Muller, H. Niel Pasley Tardus Polyhi'us Thiers and dt Laurencie Thucydides Todlehen . Vinoy Viollet-le-Duc Wagner (Reinhold) Bo. Wolff {Paid) La Defence de Belfort, 1870. De bello Peloponnesiaco. Defense de Sebastopol. Le Siege de Paris, &c., 1870-1. Memoire sur la defense de Paris, 1870-71 . Geschichte der belagerung von Strass- burg, 1870. Grundriss der Fortification. (Translated by Schaw and Pilkingtou.) Geschichte der belagerung von Belfort, 1870-71. REFERENCE TO CONTENTS. St'IiJECT. PAGE. AiiVANTAGRS of the garrison 12 attack 20-23 Alteration in trenches . 74 Ammunition for a siege . 51 „ in a battery 51, 52 Artillery, 1st position 50-59 „ 2ncl position . 70 Balloons. . . 32-35 Batardeaux, demolition of . 85 Batteries (PI. vii.) . . 48 (PI. X.) . . 62 „ approaches to . 58 „ one night . . G2 „ requirements in . GO „ sites for . .58 „ unexposed . . 59 Belfort (PI. xviii.) . . 102 Besieging force . . 54 Blockade ... 2 Bombardment ... 3 Borabproofs . . G4-06 Breaching (PI. xi.) . . 80 „ by direct fire . 83 „ „ curved fire 79-85 limits to . 83-87 Breech-loaders, advantages of .... 69 Carriages, gun, disappear- ing . . . 4G, 47 Carriages, gun, high siege . 48 „ „ sliding . 50 Cantonment of troops . 23 Choice of attack . 14,15 Close attack necessary . 87 Concealment of guns . 62, *ll Communications . . 5 Counterscarp, demolition of 97 Covering troops . 54, 72 Curved fire . . .41 Defilade of approaches . 88 Difficulties of the besieged 9, 13 Direct fire . . 40, 11 Disposition of defenders' guns . . . .19 Duties of siege troops . 53 Electric lights Embrasures, defects of „ disuse of . 38 . 48 . 50 Engineers Extent of attack External defence 9 . 71 G Fuses, slow Guns, light trench „ Gatling Gun-cotton as a burstei Guard of the trenches Handyside's engine . Indirect fire Intermediate depots . Investment, line of . „ defence of Knapsacks, air . Look-out ports . 84 . 42 . 40 . 84 75, 1^ . 30 . 57 . 25 . 7,8 10, 11 . 95 . 70 REFEKENCE TO CONTENTS. Sl'UJKd. I'AGE. Magazines, roofs of . .65 „ sites foi' . • 66 size of . 51, 52 Mines, war of . • .92 „ cases for . • 96 „ respirators for . 95 „ ventilation of . 94, 95 Mining machines . . 96 Mortars, large portable . 45 earth ... 98 „ light ... 45 Narrow parallels . .75 Nature of soil for works . 18 Night of arming . .70 Objects of sorties . 13, 14 Observatories (PL vi.) . 35 „ concealed . 36 Offensive defence . .19 Opening fire . - .71 Parallel, 1st . . 71-74 2nd and 3rd . 87 Paris (PI. i.) . . .4 „ (PI. viii.) . . 58 Park, artillery . . .25 „ engineer . . 30, 31 Parks (PI. iii.) . • 23 „ machinery for (PI. v.) 31 „ organization of . 30 „ position of . .24 Penetration of shells . . 64 Platforms . . 67, 69 Preparations for the siege . 31 Railway communications 6, 26 Railways (PI. ii.) . . 16 trench . 28-30 Reliefs, short . . .54 Saps ... 88, 80 Sap- rollers . . .91 „ cotton stuffing for . . . .91 Screens, natural . . 57 „ artificial (PI. ix.) 60, 62 Security from interruption 17 Shelter trenches . .75 Shells, Palliser. . . 84 Siege plan . . 20-23 „ preparations for . 23 Sights, raised . . .62 „ telescopic . . 44 Sorties, objects of . .13 Splinterproofs . . .64 Small galleries of descent . 97 Stages of attack . .99 Steam sappers . . .27 Strassburg (PI. iv.) . . 24 (PI. xvii.) . 102 Strength of besieging force 54 Surprise, attacks by . . 3 Telegraphy, siege . 36-38 Trains, siege, composition of . . . . 38 Trains, siege. Artillery 39-46 „ Engineer 52, 53 Tramways, rail . . 27 „ wire . 30 „ plank . 30 Transport by steam . 16,17 „ horse . . 27 „ of guns . 17, 50 Trench depots . . 25 „ railways 28-30 Wall-pieces 42-45 Working parties 73, 74 ISITYj THE ATTACK OF FORTRESSES THE FUTURE. 318. " Actum, inquit, nihil eat, nisi Poeno milite portas Frangimus, et media vexillum pono Suburra." Juv. Sat. X. 155. HE part that fortresses have played in war may be traced in the history of all nations, and in these days, while the extent of practical operations has been largely in- creased, by the substitution of railways for roads as the main lines of communication of armies in the field, the number and choice of these lines has of necessity become more limited : a fact that seems to have given increased value to the fortresses which hold such lines, and has rendered their capture more than ever necessary. Hence fortress warfare seems likely to hold an important place in future campaigns, and of all the operations of war, none are more in- fluenced by the changes in arms, and by the inven- tions of the age, than those of the attack and defence of fortresses. In general, superiority in the field alone enables the assailant to attempt the capture of a fortress, while the object he has in view must, to a great ex- tent, decide the mode of attack. A fortress may be attacked — 1st. On account of the use the defender can make Reasonsfor of it while held. '''^"^■'*- THE ATTACK OF FORTRESSES Fortresses sometinifs masked. Methods of attack. Blockade. 2nd. On account of the use to which the assailant can put it when taken. In the first case, if the fortress only threatens, with- out blocking the assailant's movements, and if time and troops can be spared, it may suffice to shut in, or even observe, the garrison. Thus in the war of 1870-71, the small fortress of Langres was masked only, because it lay to the south of the main opera- tions of the war. More often, however, we may say, in the words ascribed to Hannibal, that " nothing is decisive but the fall of the place." There are four methods to choose from, to effect this end, namely : — 1. Blockade. 2. Surprise, or assault by open force. o. Bombardment. 4. Reo-ular sieo;e. The first, which has been used since the earliest ages, is to enclose the place, so as to exclude all help from outside, and to wait for the exhaustion of the defenders' supplies. In these days particularly, wdien the result of a cam- paign is so quickly decided, the method, unless chance favours it, is generally inapplicable ; and yet we have in that of 1870-71, two of the most remarkable in- stances of its successful use. The first at Metz, where by the fortune of war, the garrison was suddenly in- creased ninefold, it could be foreseen that the re- sources that would, but for this, have lasted for months, could, under the circumstances, only hold out for weeks. ^ The second at Paris, where, though the living power of the city was under-estimated by the invader, no amount of foresight could have provided many months' supply for over two millions of inhabitants. In both these cases, therefore, a blockade was preferable, both on account of the certainty of the result, and because of the defensive capabilities of each. For the future, however, in the case of great capitals, the scheme of defence will * There were provisions in Metz for 15,000 to 20,000 men for three months, though the suppUes had been largely drawn upon before the investment. — Tiedemann. IN THE futuul:. generally be so vast, tliat a complete iiivestineiit may be impossible. In these cases a modiiied in- vestment is effected by merely occupying decisive fortified positions on the lines of sortie, so as to take them in iiank : thus the greater part of the lines of approach will only be observed, and to secure a deci- sive result, a regular siege of one or more parts of the defences may have to be proceeded with. 2nd. The capture of a fortified place by surprise is Surprise a rare event : though an assault by open force may assault. succeed when the assailants' superiority in arms is overwhelming — as, for instance, when our modern artillery is opposed to the obsolete guns and works of uncivilized races. Among well-armed nations the case is difi*erent, and the brilliant defence of Fhals- burg in 1870-71, has shown how hopeless it is to make an unprepared assault, even against the weak- est fortress, when manfully defended. The third method, that of bombardment, is only Bombardment, likely to succeed in the case of a fortress of anti- quated construction and armament, particularly when the defences include a town, exposed to the effects of the bombardment, and containing a civil popu- lation incapable of enduring its severity. Of the fortresses captured in the war of 1870-71, at least sixteen fulfilled these conditions, and yielded to bombardment. In cases where time presses, or when the result of Rtyiiar a bombardment is uncertain, the most sure, and often ^"'°^' the quickest method, is to proceed to a regular siege. Thus at Paris, Belfort, and Strassburg in 1870-71, some time, and a good deal of ammunition, were spent in fruitless bombardments. At the last place the bombardment was continued for three days by one hundred Prussian guns, besides those at Kehl (pi. iv.). All experience, including the most recent, tends to show that a fortress, well armed and well found, if unhampered by its civil population, can only be cap- tured by the fourth method, that of a regular siege. Thus even the antiquated works of Strassburg, ill armed and ill garrisoned, enclosing moreover a popu- lation comj^letely exposed to the hostile artillery. 4 THE ATTACK OF FORTRESSES were able to hold out till the German approaches almost reached the counterscarps ; while Belfort yielded, for political reasons, after a lengthened con- test, which mio-ht have been protracted far beyond the date of its surrender. As the earlier stages of a regular siege include, for all practical purposes, the operations of a blockade and of a bombardment ; while the conduct of the final assault, differs from that of an attack by open force, chiefly in the amount of preparation that is made to secure success ; it will, it is thought, be sufficient to consider only the systematic attack of fortresses. The Investment. The siege being decided on, secrecy as to the inten- tion, and speed in carrying out the investment, largely diminish the difficulties : while, to be the success- ful preliminary of a siege, it is all-important that the investment be complete; for it is not too much to say^with the lessons of Sebastopol before us — that a powerful fortress which can receive external help, is capable of a resistance almost without limit. Accord- ingly, the commander divides the intended zone of investment into sections, to each of which some unit of the force is detailed, and on which its march is directed. Thus, in 1870-71, at the investment of Paris (pi. 1.), the largest perhaps, and certainly one of the most perfectly executed operations of the kind, the Meuse army was directed on the north, its IVth Corps being ordered to extend to the Seine below the city, and the Guard Corps to occupy the region between the Creil and Soissons railways, whence the Xllth Corps had to extencl to the Marne by Yille-Evrart, where it felt the right of the third army, which occu- pied the southern region of investment. Movempiit of In the advance, the cavalry, accompanied by horse artillery, takes the lead one or two marches in front, so as to conceal the march of the main body, and by the quickness of its movements to prevent the de- fender from drawing in supplies from the neighbour- hood of the fortress, and from carrying out the investinj' force. yXe blark ckain-dcUrti line, ijr thr innfr limiL fff tJu Unt of invejtrru^nt. in, 1870-71 Thf: hU*4' luiAs sfwM- t}u> {rerman, Jr^^^rnp/ur corruiuimccUion^. TJiose dctj£ii hnruf iJif ciiinuind iifie,s Thr Te/rtfmfh Statioru'i are. aUa in blue . ihu^- . ^ Thr l,e»- £,,-,.■, uctUcli tht,,s • (>l,f..l'.t. IN THE FUTUKE. 5 demolition of bridges and the destruction of com- munications. These advanced troops at once cut the telegraph wires leading into the city. In the case referred to, the fifth and sixth cavalry divisions of the Xllth Corps were pushed twenty-four hours in advance of the infantry, with orders to cross the Seine below Paris, and form a junction with the cavalry of the Vth Corps on the south. At the moment of closing in on the place, the in- vesting bodies are, of necessity, much exposed to attack from the field troops of the fortress, and their junction with each other is the first point to be secured. In the ordinary case of a fortress like Metz, astride a river, provision must be made for nume- rous bridges both up and down stream ; and in the case of Paris, the ditficulty of the assailant was fur- ther increased, by having, in addition, to deal with the Marne above, and the Oise below the city. Pre- suming, as is most likely, that all the bridges are Communica- destroyed, the first passages are effected by the pon- "°"' toon trains, which accompany the advance of the cavalry ; and on the arrival of the infantry divisions, their field companies of engineers at once proceed to throw boat, cask, or pile bridges across the river, and to protect them from hostile attempts. The engineers also break up the lines of railway leading into the fortress, so as to prevent the defenders from using them to get in supplies, as the French did at Thion- ville in 1870, where, though the investing force had taken up rails on the Luxembourg line, the garrison managed to repair it at night, and ran in sixty waggon-loads of food.^ The engineers also drag the streams, to discover any telegraph wires laid down so as to communicate with the place. Thus at Paris, in 1870, a telegraph line, which communicated with Havre, was found in this way in the bed of the Seine.^ An underground telegraph to Tours was also discovered; but though both were tapped, the messages, being in cypher, could not be read. They were, of course, cut. ' TIedemanii. '■^ Gcetze, p. 37. tion. IN THE FUTUKE. 5 demolition of bridges and the destruction of com- munications. These advanced troops at once cut the telegraph wires leading into the city. In the case referred to, the fifth and sixth cavahy divisions of the XII til Corps were pushed twenty-four hours in advance of the infantry, with orders to cross the Seine below Paris, and form a junction with the cavalry of the Vth Corps on the south. At the moment of closing in on the place, the in- vesting bodies are, of necessity, much exposed to attack from the field troops of the fortress, and their junction with each other is the first point to be secured. In the ordinary case of a fortress like Metz, astride a river, provision must be made for nume- rous bridges both up and down stream ; and in the case of Paris, the difficulty of the assailant was fur- ther increased, by having, in addition, to deal with the Marne above, and the Oise below the city. Pre- suming, as is most likely, that all the bridges are Communica- destroyed, the first passages are effected by the pon- toon trains, which accompany the advance of the cavalry ; and on the arrival of the infantry divisions, their field companies of engineers at once proceed to throw boat, cask, or pile bridges across the river, and to protect them from hostile attempts. The engineers also break up the lines of railway leading into the fortress, so as to prevent the defenders from using them to get in supplies, as the French did at Thion- ville in 1870, where, though the investing force had taken up rails on the Luxembourg line, the garrison managed to repair it at night, and ran in sixty waggon-loads of food.^ The engineers also drag the streams, to discover any telegraph wires laid down so as to communicate with the place. Thus at Paris, in 1870, a telegraph line, which communicated with Havre, was found in this way in the bed of the Seine.^ An underground telegraph to Tours was also discovered; but though both Avere tapped, the messages, being in cypher, could not be read. They were, of course, cut. ' Tiedemann. '^ Gcetze, p. 37. External defence. 6 THE ATTACK OF FORTRESSES These services performed, two other duties must be at once proceeded with. The first, is the laying and organization of the field telegraph along the rear of the line of investment, and its connection, by semi-permanent lines, with the base of operations. The second, is to lose no time in commencing to make good important gaps in the lines of communication with the base ; particularly with a view to the arrival of the siege trains. At Strassburg (1870) the Rhine railway bridge could not, it is true, have been easily made good during the siege ; but the gap in the Miilhausen-Belfort line at Dannemarie, which might have been closed in a fortnight with the materials in the country, remained open till the end of the siege of Belfort; while but for it, the besieger, after the fall of Neu-Breisach, might have brought up his siege material by rail, almost into the trenches. At Paris too, to mention other instances, many of the Marne bridges on the Chateau-Thierry-Lagny line had been broken, and their restoration, as well as the turning of the blocked tunnel of Nanteuil, were works that proved of the utmost importance to the besieger. While these things are being seen to, the investing bodies reconnoitre the sections they are told off to hold, and proceed to draw the line of investment round the fortress. The difficulties they have to encounter, depend, to a great extent, on the character of the commander of the place, and on the com- position and strength of his troops. An active defender will make every efi'ort to go out into the country, and prepare and hold defensive positions, which not only thrust out the line of investment, and so increase its length, but also cost the assailant both time and loss in carrying them ; such actions cause the siege troops to realize their offensive power, and train them to fight. To frustrate this, and to deny the defender time to prepare, the assailant acts at once on the offensive, and endeavours to drive in the defender, till stopped by the guns of the place. The battle of the Alma (1854) was to a certain extent an instance of this, though it preceded the actual investment of the fortress ; and at Belfort, in IN THE FUTURE. / 1870, tlioug'h there was but a nucleus of good troops in the garrison/ the actual siege was delayed, for weeks, by the energetic occupation of villages, and other favourable localities in advance of the for- tress; and by the obstinate stand that was made in them. In nearly all the other sieges of the war of 1870-71, the moral effect of recent defeats seems to have paralyzed, at the first, the offensive action of the defenders ; besides which, as pointed out by Brial- mont, there is the strongest evidence, that the French garrison instructions all tended to overrate the im- portance of the close attack, as compared with that of the more distant artillery contest. Presuming that the investing force is equal to the undertaking, the earlier efforts of the garrison will, sooner or later, be overcome, and his outposts driven in to a distance of 1,000 to 1,500 yards from his works ; after which, the assailant will be able to occupy positions astride the lines of approach to the fortress, and just beyond the limits of the effective range of the fire of the place. It is evident that, in order to shorten the length of Position of line to be held by the investing troops, the distance of this line from the place, should be as small as it can be ; what it will be, must depend on the ground, as well as on the defender's numbers and the power of his guns ; but we may observe that at Paris, where the defenders' artillery was in some cases more than usually powerful, the greater part of the first, or shooting, line, was at from 3,300 to .5,000 }'ards from the forts; that of the seventh division, on the north, which was well covered by walls and trenches, being at the former distance. On the subject there is, of course, some difference of opinion. Brunner considers that, when opposed to modern siege guns, the first, or shooting line, will be at about 6,000 yards, with outposts 2,000 to 3,500 yards from the works of the fortress. Hohenlohe thinks the latter will be from 2,100 to 3,700 yards from the defences. In the " Militair Wochenblatt " ^ " The troops o£ the Hue were only one-sixth of tlie garrison.'' — Wolff. investiii": line. I 8 THE ATTACK OF FORTRESSES of April, 1873, it is considered that the line of ad- vanced pickets — i.e. the first, or shooting Ime — will be at from 3,700 to 4,100 yards from the outer line of permanent works, while the latest writer on the subject,^ places the line of investment of a large well- armed place, at a distance of from 3,270 to 4,366 yards from it. Assuming from these expressions of opinion, that the inner limit of the zone of investment is not likely, at all events, to be less than 3,000 yards from the forts — beyond which distance, we may remark, the action of shrapnel is unimportant — we at once realize one of the changes brought about by rifled siege guns. For, judging from our experience at Sebas- topol in 1854 (where the heights on which the allies first established themselves were 1,400 or 1,500 yards from the nearest defences), that, in the best days of smooth bore guns, the first line of investment might have been formed at 1,500 yards from the works instead of at 3,000 yards, as at present; we observe that in the case of a fortress having, for example, a diameter of 8,000 yards, the inner circum- ference of the zone of investment has now been in- creased from about twenty to twenty-five miles, or in the proportion of only four to five; while in a small place, with a diameter of 800 yards (about the diameter of Longdwy) its length would now be nearly doubled (fig. 14, pi. xix.) ; from which we further see that, as far as the necessity for increased extension is a difiiculty, the difiiculty of investing small fortresses has increased in these days in a greater proportion than in the case of large places.^ This, however, is, in some degree, equalized, owing to the fact that the greater concavity of a small line of in- 1 Translated from the German in the " Eevue d'Artillerie," vol. viii. pp. 289-300, and 385-403. 2 Thus the lines of investment round Paris and Metz (1870-1871) were respectively about 46 and 21 miles in extent, and were held in the first case by about 4,000, and in the second case by about 10,000 men to a mile. The investing force before Paris was actually inferior in numbers to the garrison ; while before Metz it only exceeded the garrison in the proportion of 10 to 9. IN THE FUTUKE. 9 permits of a more converging fire being brought to bear on a sortie. This increased extent of ground to ])e held by an Difficulties of investing force would, under the old conditions/ liave '''" '**''*'*^k«'1- greatly increased the diihculty of the operation; at hrst sight, therefore, the defence appears to have ^ gained considerably. Several causes, however, now I combine to outweigh this apparent gain. ^ 1st. The garrison has now increased difficulty while acting on the offensive. j 2nd. The great retaining power of the new arms, I particularly of musketry, now enables an intrenched force to withstand the direct attack of greatly superior numbers. 3rd. The use of the telegraph enables the neigh- bouring bodies of investing troops to hurry up in support of the point attacked, in less time than it takes the garrison to advance over the wide space that separates the fortress from the line of investment, and to overcome the resistance of the lines of intrench- ments. 4th. The questions of supply are now rendered much more easy of solution, by the use of the rail- ways which, in Europe at least, converge on almost all the great fortresses. Hence, provided that the investing force can hold its own long enough to intrench its positions, the results of the investments of Metz and Paris certainly justify the opinion that it can, now-a-days, retain a garrison of half, or even more than half, its own strength ; while formerly it was held, that the propor- tion should be at least three to one : its success, how- ever, will, at this stage, mainly depend on the extent to which, and the quickness with which, the ground can be prepared defensively, and the stronger the force employed, the earlier will it complete this work. It is, of course, understood that the business of the Engineersiege actual siege cannot be carried on without largely qu^ed"eariy!' increasing the ordinary strength of the engineers ^ Marshal Saxe, iu writing on investments, considered (p. 143) it was necessary to have a battahon for every 100 paces of the Hne of investment. lines of in vestment. 10 THE ATTACK OF FORTRESSES with tlie army corps, to each of which only four com- panies are assigned in the. field, and also that a body of siege artillery must be assembled, in order to work the siege guns ; but, even at this stage, the engineer duties exclusive of the preparations for defence, are, as we have seen, so many and so onerous, that it is desirable to have the whole force of engineer troops destined for the siege ready at the beginning of the investment, to co-operate with the infantry ^ in the work of fortifying their positions, and preparing the communications. Defence of The dcfencc of lines of investment, should be con- sidered as a special case of the problem of the defence of a position, and the method to be pursued should, in such case, follow the general arrangement as nearly as may be. This, for defensive purposes only, con- sists in having — 1st, a line or chain of outposts and vedettes, often some miles to the front; 2nd, a shoot- ing line, or first line of defence, on which the main stand is to be made ; 3rd, one or more defensive positions in rear of the shooting line. In the special case of an investment, the outposts can only be pushed forward, as far as the fire of the place permits. Hence the comparatively short dis- tance between the outposts and the shooting line, deprives the latter of the usual amount of warning previous to attack. And here it is necessary to point out that the spots occupied by these outposts, are to be considered as weak posts of observation,^ used to discover the first signs of a sortie, and to be aban- doned before the outposts are compromised; for all recent exj^erience shows that, owing to the ex- treme risk of retiring under fire, troops in force, once engaged, must fight where they stand. For this reason, the best ground to fight on is chosen for the shooting fine, on which the outposts fall back early; and, where they make their stand, backed up by the 1 As a matter of organization, the experience of the Germans seems to be, that the companies of technical troops (R, A. and E. E.) for the siege, should be attached to the divisions, rather than to an army corps. — HOHENLOHE, p. 5. ^ " Weak outposts — strong shooting line." — Boguslawski. IN THE FUTUKI5. 11 supports and reserves. It happens sometimes, that localities of importance must be included in the shooting line, between which and the works of the besieged, there is no cover for the outposts. These are, in such case, combined with the shooting line. To enable advanced outposts to hold out under the prehminary artillery fire, their positions should be strengthened, and these, as well as those of the shoot- ing line, being exposed to the fire of siege, instead of field and position guns, should be provided with cover, which, both in its extent and in its power of resistance, should largely exceed that usually pre- pared for an ordinary position. Accordingly we find, in the investments of Metz and Paris, that a con- siderable use was made of sunken block-houses and field-casemates.^ Again, the circumstances of the case render it necessary, to retire the artillery into, or behind, the second line of investment, where they can be covered from the preponderating fire of the fortress ; and whence they can co-operate in resisting a sortie, and can also, by direct or high angle fire, prevent a suc- cessful sortie from holding localities it may have captured in first line. Moreover, the uncertainty as to the time of the sortie makes the arrangements for the assembly of troops, and for mutual support, of extreme importance. Lastly, the object of the investing troops being to Tnvestment repulse those of the garrison, while pursuit is denied Lfence'!*' them, owing to the nearness of the fortress; they are required to act purely on the defensive, provided the investing line can be held intact. For this reason, the lines of investment should be more nearly con- tinuous than in the case of an ordinary position, and as off'ensive returns will, as a rule, only be made on a small scale, a very extended use should be made of obstacles, which indeed, during the first few days, will form the principal means of resisting night attacks;^ for, while in preparing a position with a » Cf. " R. E. Essay for 1875," p. 38, and plates. Also " P.P.E.E.," vol. XX., pp. 9 and 10. 2 Cf. "R. E. Essay for 1875," pp. 38-40. 12 THE ATTACK OF FORTRESSES given amount of time to do it, systematic and exten- sive works can often be carried out ; in the case we are considering, the day and even the hour of attack being uncertain, the works must at any moment be fit for use. Hence the character of these works is, of necessity, so irregular, that those of the Germans before Paris have been described as seeming, at first-sight, to be " the rude burrowing^ of a horde of savages." From the nature of the case, particularly with great fortresses, the zone of investment, considered as a defensive position, generally offers certain advantages and disadvantages. The extension of the suburbs that keeps pace with wealth, causes the neighbouring country to be much enclosed, built over, and wooded ; and the great roads into the place which are the natural hues of advance for sorties, are, at the same time, the usual sites for the outlying villages and hamlets. On the other hand the roads, being mostly radial rather than lateral, great labour may often have to be bestowed by the investing army on their lateral communications; while, for tactical purposes little or no use can be made of the railways, though, as we shall notice further on, portions of these form iron mines of great value in the making of siege works. Advantages of The troops of the garrison benefit by certain spe- the garrison, ^[^i advantages, and suffer from special disadvantages. The advantages are : — 1st. They can attack the investing troops at any time, with little warning, and from a secure base. 2nd. Having, in some cases, prepared the way by cannonading the defensive works of the besieger, they can advance rapidly, with a wide front, unimpeded by trains, with the infantry unencumbered with their packs, and supported moreover, for some dis- tance, by the fire of the guns of the fortress. 3rd. They are, or should be, thoroughly acquainted with the ground, both for mancEUvring purposes, and 1 Viollct-le-Duc. IN THE FUTURE. 13 also for the use of high angle fire at long ranges, in order to disturb the jjesieger's cantonments.^ 4th. They have peculiar facilities for making night attacks, a fact that obliges the investing troops to be constantly on the alert, and ready to assemble at their alarm posts ; besides which, they must make nightly use of numerous patrols. On the other hand the besieged cannot, from the Disadvan- nature of the case, execute any wide turning move- *^^^^' ment, and are driven to employ the front attack ; and also, in the case of an ordinary sortie, they have the cheerless task of " coming out to go back again." We have now to consider what objects the garrison Objects of may hope to gain by attacking the lines of invest- ^°'"''^^- ment. These objects are : — 1st. To check the progress of the works of in- vestment ; to hinder their approach to the fortress ; and generally to delay the establishment of the in- vestment, preparatory to the siege ; as well as to accus- tom the untrained troops of the garrison to manoeuvre in the field. 2nd. To relieve a too numerous garrison of some of its numbers, by breaking through with the surplus. 3rd. To act in concert with an external force, either a convoy, or a relieving army. The difiiculties in effecting the first object, plainly increase with the amount of time the investing force is allowed for preparation. As regards the second, in the exceptional case of a garrison too large for the resources of the place — a circumstance which produced such fatal results at Metz in 1870 — the object of a sortie, intended to break through, is not so easily attained as it seems to be ; for, presuming that the investing lines are carried, the force, although it may have cut its way through, is without a base of operations, and is not likely to have succeeded in bringing out large trains ; hence, if it be not in sufiicient strength to have done this, 1 Boguslawski mentions that the French shells so used at Paris, ranged 10,000 or 11,000 paces. 14 THE ATTACK OF FORTRESSES and also to pursue its advantage by rolling up the defensive lines of the besieger, it will probably itself fall a victim to attacks in flank, while in movement to secure a new base of operations. Thus, even had the French succeeded in breaking through the deep German formations before Metz, numbering, as we have already seen, about 10,000 men to the mile, and strongly intrenched, they would have found themselves at least four marches from any place they could have used as a base for supplies ; and would, as we now learn, have been pursued by two cavalry divisions, and attacked by four army corps/ In fact, it is only where the effort is made in co-operation with a rehe\dng army, that a garrison is Hkely to obtain decisive results against a strong investing force. While, therefore, this force is engaged in making up for its extension by strengthening its front, attempts to raise the siege may be anticipated, and must be provided against by a covering force, and sometimes also by defensive preparations ; but in any case, by preventing the garrison from communi- cating with the external force, and organizing such joint action. The critical condition of the German Army before Paris in 1870, threatened as it was, up to the surrender of Metz, by the French Army of the Loire, is now a matter of history, and the protection aftbrded it by Von der Tann's detachment is in the recollection of everyone : while the attempts of Faid- herbe and Bourbaki to raise the sieges of Peronne and Belfort, were, with difficulty, frustrated by the successful actions of the covering armies at Bapaume, and on the Lisaine. Choice of Fronts to be Attacked. Choice of The question "where to attack" must be considered attack. from the moment the siege is thoughtr of, and the Intelligence Department should provide all available information for the use of the besieger. From the moment of his arrival at the place, the problem is studied on the ground itself, by means of reconnais- ^ Paul lis. IN THE FUTUliE. 15 sauces, which, however, should not attract the atten- tion of the garrison. For this there is generally no lack of time, owing to the necessary delays in getting up the siege trains, and preparing the siege materials. Again, in the case of a vast fortress, instead of one There may tack, two or more may be decided on, while the I'l^^no'^le attack. ecting the choice. attack, first preliminaries of a siege may, in addition, be commenced on other points, with a view to distract and weaken the defender's resistance. The siege of Paris in 1870-71 gives examples of all these; for, while attacks were made on the southern and north- ern forts, a demonstration of intention to besiege was made against the advanced positions of Mont Avron and the eastern forts. As, however, the general ar- rangements of each operation will be similar, we pro- pose to deal with one only. In deciding on the base of attack, the following Points points are to be considered in choosing the most fit field :— 1. Which region of the investment will be most convenient for the arrival and parking of the siege trains, and siege material, and for the supply of the siege troops? 2. Which region is most secure from external interference by a relieving force? 3. Which will give the besieger the most favour- able ground for attack? The considerations as to the relative power of the difterent sections of the defences may be classed thus — 1. Against which section will a successful attack lead most directly to the final result? 2. To what extent do the works of each section command the distant foreground? 3. In what way do they bear on the ground close to them ? 4. AVhat support do they give to each other, and for the making of counter approaches ; and to w4iat extent, and in what spots are the latter practicable ? 5. What is the nature and construction of the works composing the section, and their passive power of re- sistance ? 16 THE ATTACK OF FORTRESSES Facilities for transport. Transport by steam. In considering the question of transport, it is im- possible to forget the lesson we ourselves learned at Sebastopol in 1854-55, from the difficulty we experi- enced in transporting materials for the short distance that separated Balaclava from the trenches. Had Balaclava been a hundred miles from the fortress, we may safely say that, without a railway, the allies could not have carried on the siege. Since then the weight of the siege material, and especially of the ammuni- tion, has largely increased. For example, at the siege of Strassburg in 1870, the Germans, we are told, fired sometimes as much as sixty tons of am- munition in a day.' In one sense the work of the siege may be said to commence at the foundry or arsenal, the guns being but the funnels for distributing the iron stream that flows therefrom along the channels of communi- cation. Where a waterway, a great river, for instance, which steamers can use, is available from the base, it is, perhaps, the most convenient; without it, a railway is almost an absolute necessity for any great inland siege; hence there will be a strong reason for selecting, as the ground for attack, the point where the railway, or other communication from the base, most nearly approaches the fortress. Thus at Strassburg (pis. ii. and iv.) in 1870, the Weissemburg- Hagenau line ran through the besieger's works, and connected them with Germany. The besieger at Belfort, after the fall of Schlettstadt, had railway communication to Dannemarie from Strassburg; while, in the case of Paris, circumstances were much less favourable; for, though the direct line, Nancy- Chalons, was cleared by the taking of Toul on the 24th of September, it only approached the south- east portion of the capital; while the northern line through Metz, M^zieres, and Rheims was closed by Montm^dy, till the 14th of December. Hence, Lagny on the first-named line, and Nanteuil became the ' Fifteen tons at Paris according to Hohenlohe. " At Belfort the Germans fired 99,453 rounds, weighing about 2,200 tons, in 73 days, or over 1,360 rounds a day." — Wolff, Appendix, p. 8. C^jj.l'.lC IN THE FUTURE. 17 great points of debarkation; and at the latter, the artillery and engineer siege trains had to be un- loaded, and conveyed thence, by road, to the parks at Villecoublay, a distance of nearly forty miles. For this service the artillery alone required 900 horsed waggons. This circumstance dc^layed the siege opera- tions for many weeks, and would have been very serious, had the invader depended for success on the siege alone. In addition, as the assailant will be in greater strength where the siege takes place, than elsewhere along the line of investment, the nearness of the communication will be most valuable here for the provisioning of the troops.^ Indeed, the business of supply alone, in a large operation, is a matter of extraordinary difficulty, if dependent on roads only : so much so, that before Paris, even with two railways, the transport of siege material had often to be stopped on account of the requirements of the troops. Next to the railways, the nature and condition of the roads must be considered; for, however convenient the former may be, large use must always be made of the latter: these should also be looked to with a view to a possible retreat. Other points are the local resources in the way of wood and water; the relative healthiness of the region, particularly in view of a protracted siege ; the extent to which the siege troops can be housed in outlying villages, &c.; and the distances within which bnisliwood and timber for siege purposes can be procured. The security of the siege troops from external SecuHty from interruption, is of course very important. Thus the '"'*'" "i'^'*^"- site of the German attack of Belfort in 1870-71, had the advantao^e of beino- on the side furthest removed from the probable advance of a relievmg force. 1 A train of 60 railway waggons carries the supplies for a clay for 60,000 men and 12,000 horses. Such a train can seldom travel more than 180 miles in 2-4 hours ; only one can be run every hour, and it takes about 10 hours to load, and the same to unload it. A heavy siege gun, completely equipped, and with 500 rounds, requires about five trucks. See M. P. R. A. I., December, 1871, p. 27. ~ Cf. Royal Engineer Essay of 1875. pi. i. C RAILWAYS IN THE WAR CASSEL' mezierel VrTves rWEDY j/LujarmBjbuJiG ■lAGNY £p.Mra7*5ir ~Vt fVERDU 'CoiUommier ^CHALONS m 2 O z m m 73 > 73 O c > en OppP. 23. Xmlay a mUi^ S GudtS^lhlhirn. IN THE FUTURE. 23 straight line ; and we find the assaihmt, while retain- ing, to some extent, his power of concentration, de- prived of his enveloping power, as ivgards the whole line of defence. We conclude therefore, that under the new state of things, the power of resistance of small fortresses has relatively decreased: the more so as their delences are now exposed to be bombarded in reverse^ by the far ranging guns of the siege trains. PREPARATIONS FOR THE SIEGE. When the army of investment has succeeded in en- closing the fortress, has intrenched itself against the sorties of the garrison, has taken measures to guard itself from external interruption, and when the point of attack has been decided on, the business of the siege begins. The question of sheltering the siege troops Cantonment ot must of course depend on circumstances. If there be many villages at hand, and available, it may suffice, in great measure, to use them. When, how- ever, the troops have to march to and fro some miles to the siege works, the fatigue of doing so, may seriously interfere with the execution of these works ; or, if the cantonments be so situated as to hinder their rapid assembly, their power of resisting sorties may be diminished;^ hence it may be necessary to make huts for a portion of them, as was done in many instances during the war of 1870-71, as, for example, at Gonesse, north of Paris ; at Metz ; and in the wood of Bosmont, before Belfort; though in most cases the villages sufficed. At Sebastopol, on the other hand, shelter had to be provided for almost all the troops, and the work of sheltering them was so onerous, that the siege works had to be left undone while it was being carried out. * "In the instructions for the siege of Belfort in 1870, it was laid down that the cantonments were to be such as to permit of the men getting under arms in five minutes." — Wolff, Appendix, p. 6. troops. 24 THE ATTACK OF FOKTRESSES Positions While the troops are being housed, the exact posi- plrks. tions of the artillery and engineer parks are decided on, and the organization of them begun. Owing to the fatal consequences that might befall the whole operation, in case a successful sortie could reach them, and destroy their contents ; it is necessary, in choos- ing sites for them, to fix on spots in rear of the defences of investment, and out of sight of the fortress. So placed, they will generally be at such a distance from the latter, as to be secure from the effects of random fire.^ The distance of the artillery and engineer parks from the place, will probably be, for the former 3^ to 4|, and for the latter 3 to 3| miles ; but must depend on circumstances : at the attack on the northern forts of Paris, where the ground was somewhat open, both the siege parks seem to have been near the Patte d'Oie, east of Gonesse, and about 8,700 yards from the forts ; Avhile, for the southern attack, the parks were at Yilla- Coublay (pis. i. and iii.), distant about 5,500 yards from the works, but covered by the wood of Clamart. Some uneasiness was felt about the position of these last, and considerable labour was spent in intrenching them.^ Again, at Strassburg (pi. iv.) the artillery park north of Mundolsheim was 6,300 yards, and the engi- neer park at SoufFelswheirheim was about 4,700 yards from the place. In the attacks of the smaller places in 1870-71, it was possible, without risk, to place the parks much closer. Thus, before M^zieres, the engineer park was at Francheville, 3,500 yards from the fortress, while at Soissons, the artillery and engineer parks were re- spectively distant 4,100 and 3,300 yards from the place, and on the same road. An Austrian writer^ on the future of sieges has ^ According to Tiedemann, the French shells from Strassburg, fired the village of Mittelhaushergen, distant 4,600 yards (pi. iv.). ^ Brunner suggests a distance of 6,000 yards from the most ad- vanced works, for the siege camp, and parks ; but recommends that the main magazine for the artilleiy park be 8,000 yards back (p. 10). 3 In the "Mihtair \\^oclieublatt," for April, 1S73. RNIK- 24 THE ATTACK OF FOllTRESSES Positions While the troops are being housed, the exact posi- pais. tions of the artillery and engineer parks are decided on, and the organization of them begun. Owing to the fatal consequences that might befall the whole operation, in case a successful sortie could reach them, and destroy their contents ; it is necessary, in choos- ing sites for them, to fix on spots in rear of the defences of investment, and out of sight of the fortress. So placed, they will generally be at such a distance from the latter, as to be secure from the effects of random fire.^ The distance of the artillery and engineer parks from the place, will probably be, for the former 3J to 4^, and for the latter 3 to 3^ miles ; but must depend on circumstances : at the attack on the northern forts of Paris, where the ground was somewhat open, both the siege parks seem to have been near the Patte d'Oie, east of Gonesse, and about 8,700 yards from the forts ; Avhile, for the southern attack, the parks were at Villa- Coublay (pis. i. and iii.), distant about 5,500 yards from the works, but covered by the wood of Clamart. Some uneasiness was felt about the position of these last, and considerable labour was spent in intrenching them.^ Again, at Strassburg (pi. iv.) the artillery park north of Mundolsheim was 6,300 yards, and the engi- neer park at Souffelswheirheim was about 4,700 yards from the place. In the attacks of the smaller places in 1870-71, it Avas possible, without risk, to place the parks much closer. Thus, before M(^zieres, the engineer park was at Francheville, 3,500 yards from the fortress, while at Soissons, the artillery and engineer parks were re- spectively distant 4,100 and 3,300 yards from the place, and on the same road. An Austrian writer^ on the future of sieges has * According to Tiedemann, the French shells fronn Strassburg, fired the village of Mittelhaushergen, distant 4,600 yards (pi. iv.). * Brunner suggests a distance of 6,0U0 yards from the most ad- vanced vvorks, for the siege camp, and parks ; but recommends that the main magazine for the artilleiy park be 8,000 yards back (p. 19). 3 In the "Militair Wochenblatt," for April, 1873. Outskirts of sie'Sjarks FIRST WORKs"oMNVESTMENT 1870. w -^^^ v\i \ IN THE FUTURE. 2.5 pointed out that, with the iTicrcfised extent of front of attack, it is no longer possible to have one en- gineer park; and that the battalions of engineers should each have its own park in its cantonments. The Germans, however, after the widest experience, have decided on having general parks; but, to get over the difficulties, which must occur with a wide front of attack, they provide the diiferent sections with intermediate depots, and keep them supplied intermediate from the park. Of these depots there are usually three ; '^^p*'"*- viz., for the right, centre, and left attacks (as at Strassburg in 1870); they are placed out of sight of the fortress, and distant from it 1,-500 to 2,500 yards. ^ These contain the necessary supplies for a " siege day," and from them supplies are issued to moveable trench depots^ which are made to progress Trench with the works, and contain supplies for immediate "^^°^' use, laid in the reverse of parallels, &c., often where the approaches join them. With us, each engineer held company has its own equipment, all of which, except perhaps the mining tools, &c., it might retain at its own cantonments; but the siege equip- ment and stores are, doubtless, most generally avail- able, if placed in a main park, under the control of an officer who, with his staff, is responsible for the entire working of the supplies for siege pur- poses. Gillmore^ points out that this park director should be empowered to purchase such stores as he may urgently require ; that he should always have the command of a limited number of teams, waggons, &c., to meet sudden calls; and that his books should, at all times, show the state and place of all stores, and particularly of the siege material that is being worked up. By feeding the depots from the jmrk, they are kept supplied with none but ser- viceable tools and materials. All tools and stores unfit for use, are passed back at once to the park, where they are dealt with as required. In the artillery park the arrangement is somewhat Artillery ^ ° pnrk. * Gcetze (p, 174) incntions two such, before Paris, at Meiuloii and Clamart. - Pp. 237-240. 26 THE ATTACK OF FOKTRESSES different, as most of the siege guns are in time, told off to the different siege companies. The reserve, however, as well as the mortars and special pieces, are kept in charge of the park director, who also has charge of — 1st. The artillery siege stores, forges, s^^are car- riages, and moveable platforms. 2nd. The ammunition and laboratory. 3rd. The general powder magazine and the filling and shifting sheds. From this park are supplied any intermediate depots of ammunition ; while the magazines, and shell recesses in the batteries correspond to the engineer trench depots. Importance of Prcsumiug, for the reasons already given, that in raiTwiy'TOm-^" iiiost large sicgcs there will be at least one railway, munications. or Water communicatiou, approaching the parks; it becomes very desirable to connect them therewith by rails. The line from Balaclava to the trenches before Sebastopol, was the first instance of this being done ; though, from want of previous practice and organization, it took eight months to make the 8f miles. Tiedemann mentions that, at the siege of Longdwy, in 1870, the German engineers recon- structed 4f miles of railway, from Longuyon to Cons-la-Grandeville, where stood their general siege park ; but the largest work of the kind was the field railway between Remilly and Pont-a-Mousson, made in the same war ; more, however, for strategical than for siege purposes. The site, which had been ex- amined before the war, was again surveyed on the 14th — 16th of August,^ after which the 22 miles of ^ " About 2,750 were civilians of the country, and, in addition, four companies of engineers and two railway companies, and a park of over 330 carriages. The line was almost all without ballast ; the ruling gradient was 1 in 40 ; the radius of the least curve about 210 yards ; while that at Nanteuil was as little as 133 yards. The rails were got from neighbouring lines ; the sleepers were cut on the spot or brought up. The works were a few small bridges, and very low cuttings, and embankments of only four or five feet. The engine could only draw four trucks at a time, as the line was very rough for want of ballast. The bridge over the Moselle was carried away after the line was made." — Jacqmin, pp. 326-328. IN THE FUTURE. 27 line were formed in forty-eight days, by the daily hibour of about 4,000 men. The short line at Nantciiil, 5,450 yards in length, took twenty-one days to com- plete (pi. ii.). It generally happens that portions of the line near the fortress cannot be used for traffic ; and from them rails and other materials may often be obtained to make the new portion, which should, of course, have the same gauge, so as to save break of bulk. Any railway over which waggons can pass, even at low speed, is better than a road, even if it be too rough for ordinary engines: in which case, the steam sap- Use of steam pers, which have spare railway wheels, may be used "''pp^'^* to get the trucks along, one or two at a time, over steep inclines or weak bridges.^ Animals, too, may Horses, &c. be worked for the same purpose, and will have a much greater effective power of draught than on roads.^ Only a single line will, generally, be possible ; but Lo?p and it should have a loop, long enough to take the longest ^' '"^*' trains, halfway between the main line and park sta- tion. At the latter there should be several long sidings, furnished with a water supply for the engines, and with swinging derricks, and side and end unload- ing platforms, these last being required for getting guns off the waggons. In addition, a telegraph will a telegraph be necessary from the main line to the park, with a required." "^ station at the loop, so as to work the traffic with the assistance of signals. ^ Provided, of course, that the gauge be the ordinary EngHsh gauge of 4 ft. 8| in. Under special circumstances, these engines may be used as traction engines ; but, as a rule, the fuel consumed is out of proportion to the work done, and exceeds the weight of forage for the same horse-power. There are four to each army corps. 2 On the level, with low speeds, the effort of traction, on different kinds of roads, has been found to be as follows, viz. : On an unmade track . . 300 lbs. a ton, or 1 in 8. On the best coach roads . 45 lbs. „ or 1 in 50. On a plank track . . . 30 lbs. „ or 1 in 75, On a contractor's railway . 15 lbs. „ or 1 in 150. On a permanent railway . 8 lbs. ,, or 1 in 280. Tlie disproportion decreases as the gradient becomes steep, and for tramways, gradients of from 1 in 30 to 1 in 25, according to their greater or less length, seem about the steepest practicable. At low speeds a horse can exert a pull of about 100 lbs. 28 THE ATTACK OF PORTKESSES A railway from the parks to the 8iege-works. Trench rail- Description of mil. When it is considered that the distance between the parks and the intermediate depots may be above two miles, it is plain that a further extension of the railway from the parks to, or towards, those depots, is very desirable; particularly for the purpose of bringing up the large daily supplies of ammunition that are, as we have already seen, now required. Having decided to continue the railway, it next becomes a question how best to do so. In the first place, if no trench railway rolling-stock can be brought up, the local gauge must be continued as far as may be : if possible to the intermediate depots and first artillery position. This arrangement saves break of bulk, but, on the other hand, the width of gauge adds greatly to the labour of construction, and is unsuitable for a further advance along siege approaches, where sharp curves may be unavoidable. Next, supposing that narrow-gauge rolling-stock can be brought up, though their weight may hinder the bringing up of special rails ; in such case it would, generally, be best to form a narrow-gauge line with the local rails, from the parks onwards. This break of gauge at the parks, is not, except in the case of guns, of great importance : because the demand for rolling-stock between the parks and the base will be so great, and the siding space so comparatively small, that the trucks could seldom be kept loaded at the parks till their contents were wanted at the front. As, however, the supply of local rails available for trench railways would rarely suffice, and would, generally, be much more clumsy than need be ; it will often be worth while to bring up special materials for a narrow-gauge line in advance of the parks ; pro- vided that the difficulties of transport be not excessive. For narrow-gauge lines, the points to be considered are : — 1. The description of rail, if local rails be not used, 2. The width of gauge. 3. The means of locomotion. If circumstances justify or compel the bringing up of special rails, instead of the use of the local rails, IN THE FUTURE. 29 they should be as light as will answer; flat-footed, so as to be iixed without chairs; and of wrought iron, not steel, so as to permit of being easily bent and cut. When timber is plentiful on the spot, very light rails, with numerous broad sleepers, may be used; when not so, heavier rails and fcAver sleepers may be better. Kails from 15 to 24 lbs. to the yard will generally he found to answer. One pattern of rail, and one method of lixing should, of course, be used throughout — a lesson that our Abyssinian experience taught us to our cost. The width of gauge should be as small as will width of permit the carriage of the loads, in ordcsr to allow of ^''"^'^* the use of sharp curves, and to diminish the size of the trucks, and also to keep them as much under cover as possible : at the same time it must be wide enough for use with horses. For this, a gauge as narrow as 18 in. has been found practicable; and wide enough for the carriage, at low speeds, of considerable loads.' For reasons that we shall consider further on, we may assume that the siege batteries will seldom be much in advance of the position of the first parallel. It is doubtful, therefore, that it will be worth while to carry a trench railway further, except in short lengths, for mining or other special work. As to the use of railway engines at a siege, it is well Means of known that, besides being incapable of unceasing work, or long-continued effort on steep gradients, horses require a greater weight of forage, for the ' The trench railway useil at Chatliam had, at first, a gauge of 2 ft., with rails 15 lbs. to a yard, and with sleepers 2 ft. G in. apart. Since then an 18 in. gauge and a 241b. rail have been decided on, because this gauge is now in use in England, and plant fi'oni it, can be got at need. For this gauge our siege equipment provides, for each army corps — 3 engines, 5 trollies, and 25 sets of 18 ft. bogies, as well as 200 tons of rails and 11,000 sleepers, i. e,, enough for about 8,000 yards of single line with curves, sidings, etc. The weight of this por- tion of equipment would be a good deal over 300 tons ; while that of a Prussian engineer siege train complete is only about 150 or 1(30 tons. This might not be a great difficulty when working near a sea base, as at Sebastopol ; or provided there be railway communication with the base ; but would bo entirely beyond the ordinary means of transport, in many inland operations. locomotion. 30 THE ATTACK OF FORTRESSES work they do even on tramways, than the weight of coals necessary for an engine: it is plain therefore that the latter should be used as far as possible : but an engine, having to move along a definite line, is an easy mark, unless it be so screened that its exact position is uncertain. Hence, except when so screened, it will not be practicable to use engines within the effective range of the fortress artillery, and then not further than the first artillery position. In ex- ceptional cases, as, for instance, on steep gradients, it may be an advantage to use locomotives as stationary eno-ines.^ In cases where the prolongation of the ordinary line, or the transport of special materials is impracticable ; it may still be possible either to form plank tramways, or to provide and make wire tram- way lines, such as are used in many mining districts : these seem peculiarly suitable for transporting am- munition ; while the materials they are composed of are themselves comparatively light, and easily brought up. ORGANIZATION OF A PARK. In addition to the questions of communications and site, the points to be attended to in organizing a park are : — 1st. The adoption of a compact arrangement, which will aid supervision, without crowding the stores. 2nd. The separation and marking of the stores according to their uses, bearing in mind the greater or less frequency of demand. 3rd. The placing of the heavier stores in the posi- tions from whence they can be most easily moved. 4th. The provision of cover for those stores which might be damaged by exposure. 5th. The provision of workshops and hut, shed, and stable accommodation. 6th. The water supply and drainage of the park, and the internal communications. • Handysidc's engines, which can he attached to the rails, draw loads up 1 in 10. I Pi V. Steam JMaciiinery for an Engineer Park. IN THE FUTURE. 31 7th. The means of telegraphing to the interme- diate de])uts, and elsewhere. 8th. The constant employment of the same staff. 9th. The special precautions necessary for securing the park from fire, and the magazines from explo- sions.* The following subdivision of the site of the engineer En^inepr park has been found convenient in practice, viz. : — P*"'^' Quarters for the park director and staff, and guard- room for the j)ark guard. A place for waggons, timber carts, barrows, &c. Ditto for brushwood work. Ditto for materials. Ditto for intrenching tools. Ditto for sapping tools. Ditto for mining tools, &c. Ditto for miscellaneous implements and stores. Ditto for a magazine for mining powder and for gun-cotton.^ Ditto for workshops, saw-pits, sheds for engines, and steam machinery (pi. v.). Ditto for a canteen. The same system is followed in the intermediate depots as far as it is applicable. PREPARATIONS FOR A SIEGE. After the assembly of the siege troops on the scene of action, not a little time may elapse before the arrival of the trains; time that may, however, be profitably spent in getting ready for the siege in several ways, in addition to preparing the parks and their communications, and securing defensively any ground wrested from the besieged. In the first place, the resources of the neighbourhood, in the way 1 In the engineer park the wet gun-cotton might be kept in metal- lined powder cases, sunk in the ground ; a drying shed might be required to prepare a portion of it for use ; but, if possible, enough dry should be kept in store, separate from the wet, the detonators being also ko[)t apart from the cotton. 32 THE ATTACK OF FORTRESSES Collection of stores and brushwood. of tools and materials, are collected. Thus Goetze mentions, that at the siege of Paris in 1870, the whole country, as far as Orleans, was requisitioned for nails, wire, &c. The cutting and making up of brushwood also, is at once begun. Brushwood being bulky and troublesome to shift, every care should be taken to avoid moving it more than need be. When the troops may be required to resist sorties at short notice near their cantonments, it may often be best to brins: the brushwood to the cantonments, to be made up on the spot; m other cases, to save trans- port, it may be worked up where cut, particularly when the materials are near the intermediate depots, to which the gabions and fascines may, in such case, be carried direct.^ In addition, some brushwood should be stored in the engineer park, to be made up for special purposes, which occur from time to time. In this work of carrying, the German field-artillery teams, the cavalry, and the pontoon trains largely assisted in 1870. COMMENCEMENT OF THE SIEGE WORKS. Balloon observatories. Besides the brushwood work, those portions of the siege works which are screened from the fortress, within the line of investment, may be at once com- menced ; the necessary reconnaissances too, must somehow be made. In this respect we have seen, that the besieger is now much hindered by his in- ability to get near the place ; and the only remedy that appears hopeful, is the use of balloon and other observatories. As, up to the present time, the navigation of balloons has not been effected to any extent, the fortress can only use them as a means of sending out mes- sages, as was done in Paris, and in one or two other places in France, in 1870-71. There is nothing, how- 1 The quantity of brushwood estimated as wanted for a siege, should be exceeded in tlie preparation, by at least one-fourth. IN THE FUTURE. 33 ever, to prevent an investing force from nsing the wind, to carry a balloon fi'om one ])oint to another of their line, so as to see into the fortress, and even, as has been suggested, to shell it with gun-cotton. Captive or stationary balloons supply each side with the means, in still weather, of overlooking the works of the other. The French in Paris (1870-71 ) used a captive balloon in this way, and, by its means, discovered that the Germans were em- ployed on the defences of Pierrefitte. The observer signalled to Fort la Briche, which opened at 3,000 metres, and stopped the infantry working parties. The gas balloons they used in that siege had a capa- city of about 20,000 cubic feet, and carried three men. At Strassburg and Paris, in 1870-71, a sta- tionary balloon was tried for the Germans, by an American, but without success. At Aldershot, in I860, a captive balloon made ten or twelve ascents to a height of 1,100 or 1,200 feet, and was found quite manageable in still weather. For the purpose of observing at a siege, as the field of operations is limited, only a small ascent of from 300 to 600 feet is necessary. The balloon is best secured by a light steel Avire rope, and two silk or hemp ropes, as in fig. 15.^ It must have buoyancy enough to sustain an observer, in telegraphic communication with the earth, and an aeronaut. This is not difficult to arrange in a great fortress, where coal gas can be got f but, though gas works may sometimes be found by the besieger, in the towns he occupies near the ' The insulation of this steel rope might he so arranged, that it would act as a telegraphic conductor, instead of using a separate wire. Besides, it seems best to use at least one metal rope, as all others wear quickly, and may rot without showing it. 800 feet of ^-'m. steel rope (of fine wires for suppleness) would weigh 70 lbs., and have a breaking resistance of 1 ton. 1,600 feet of l^^-in. silk rope would weigh 129 lbs. and he of the same strength. 2 In considering the use of coal gas, it is to he remembered that at certain stages of production, a much lighter, and therefore more suitable gas is obtained, than at others. The French war balloon, taken to Italy in 1859, was filled with coal gas at Milan, and brought Jillcd to Gorgonzola, twenty miles off. It held .30,000 cubic feet. D 34 THE ATTACK OF FORTRESSES Compi-esseJ gas for balloons. Local means of inflating balloons. fortress, whence the filled balloon can be led to the point of ascent; the contrary will often be the case. Monsieur Godard proposes to have four small balloons of manageable size for each captive balloon ; and to fill and bring up these to the latter. When, how- ever, the distance is great, it may be practicable and, in certain cases, with a sea base for instance, more convenient, to bring up compressed gas for the be- siegers' use. Coal gas can be compressed to one- fortieth of its bulk, by means of an engine of three or four horse-power ; in this way the gas required for a balloon, say 16,000 cubic feet, could be reduced to 400 cubic feet ; the cliief difficulty would be the weight of the reservoirs, which, even if of steel, would pro- bably weigh altogether about seven or eight tons, and would require two railway trucks for their transport. Hydrogen gas can be compressed to the same extent, and, being more buoyant,' about 13,000 to 14,000 cubic feet would answer the purpose, particularly as the buo3'ancy of pure hydrogen, such as could be brought up, is nearly 70 lbs., while that of light coal gas is only 50 lbs. per 1,000 cubic feet. Supposing, however, that there are no means on the spot for making coal gas, and that we cannot bring up compressed gas ; we must seek for local means of inflating balloons, for siege and field opera- tions. Hydrogen gas, the smoke of straw or wool, and hot air are the means that have been, so far, used with any success. The production of the first, in large quantities, requires time and heavy appara- tus ; and yet the armies of the first French Republic made large use of hydrogen captive balloons, par- ticularly at the battle of Fleurus and at the siege of Ehrenbreitstein ; and even shifted a filled one from Charleroy to Maubeuge. The method that has been ^ The buoyancy of 1,000 feet of hydrogen, as made in the field, is roughly 62-5 lbs. ; and of common coal gas about 45 lbs., or in the pro- portion of 12-5 to 9. The weight of a balloon with ballast for a small ascent, and with telegraph and cables, should be under 800 or 900 lbs., including two men. A surplus buoyancy of 10 to 20 lbs. being enough to start the ascent. Pkte^VI. ;y>r^t<;) ScmiOafM i Opp.r. 35 IN THE FUTURE. 35 found to answer best for making hydrogen, seems to be to pass steam over red-hot iron or zinc. The .American balloons used in 1862-3, were inflated with hydrogen, prepared in three or four hours by the sulphuric acid process, and were much used with M'Clellan's army.^ The production of hydrogen is, therefore, j^ossijjle at a siege; but, apart from tlu; difficulty of making it, there is another point against its use, namely, the great diffusive power of the gas, which makes the choice of the fabric for the balloon especially difficult. The employment of a double balloon may, however, prove to ])e a remedy. Of the other two modes of inflation, hot air seems Hot-ni.- to promise best f and it is proposed that the balloon be inflated, in the first instance, by any convenient number of sources of heat, and the air be kept hot, during the ascent, by a very powerful lamp, burning vegetable oil. Even supposing, however, that a bal- loon is available, its use is so dependent on weather, &c., that more reliable methods of observation must also be employed. Other observatories are of two kinds : — other obser- 1st. Those which are beyond the effective fire of '^^°"*'''- the defender, and depend for their use on the height Elevated ' \ ^ observatories. to which they are raised. 2nd. Those which are chiefly valuable from their position, and which may be exposed to fire. , To equip the first, the R.E. siege train should have [( a few very powerful telescopes. This kind may be ' placed on existing objects, churches, trees, &c., or may be built up of timber (pi. vi). Observatories of this class, some of them over 140 feet high, were used at the siege of Charleston. "^ They were pro- tected at the base by a defensible stockade. One of the best forms for the field is the ladder- tripod." This constitutes a portable observatory, » P. P. P. E., vol. xii., papers x. to xii. 2 The buoyancy of white smoke is about 225 lbs. to 1,000 cubic feet ; hence Montgolfier balloons must be very large ; but they are inflated in half an hour. A captive ISIontgolirer balloon was used for the French at Solferino in 1859. 2 Gillmore, p. 291. * P. P. R. E., vol. vii., p. 43. observatories. telej,Tapliy. 36 THE ATTACK OF FORTRESSES which can be raised in twenty minutes to a height of forty feet. Conceaiea Thc scconcl kind, usually take the form of blind- ages, with shell-proof roofs if exposed; or they may be concealed behind any convenient objects. In all cases they should have telegraphic communication with the rear, and the same two observers should always take alternative reliefs.^ Siege ^ While discussing these collateral questions, it will not be out of place to consider the subject of tele- graphy as applied to siege purposes. The lines of telegraph employed are of three kinds : — 1st. Those for connecting the head-quarters with the base of operations. 2nd. Those for communicating along the line of investment. 3rd. Those for connecting the different operations of the siege itself. For the first kind the line will be semi-permanent, aiul ordinary telegraphic materials will be used.^ For the second, the arrangements will be similar to those made in the case of an ordinary defensive position, for which the eighteen miles of wire with the telegraph half-troop attached to each army corps, is sufficient. For the third, the lines must be so arranged as to give the siege troops the means of calling for help, as soon as they are threatened by a great sortie ; to enable the siege batteries to work collectively, by carrying a branch wire to some point situated cen- trally with reference to each group of batteries ; and also, by carrying forward the telegraph from the siege head-quarters, to the quarters of the staff for the day, and from thence into some blinded observa- tories in the advanced trenches. From these points, the effects of the artillery fire, the earliest notice of a sortie, or the evacuation of a work, may, at once, be reported, and thus immediate action when needful 1 P. P. R. E., vol. XX., pi. xxxii., fig. 34. * According to the " Regulations for the Supply of Stores to an Army in the Field," our reserve telegraph equipment is to be 100 miles of double line of bare wire, with 10 stations. IN THE FUTURE. ' 87 may be secured ; or, on the otlier hand, the siege troops may be saved fiom uniiecessai'y alarms, or enal)led to communicate with the parks tor su})plies. For these purposes, our siege equipment provides eighteen miles of galvanized bare wire, and eighteen miles of insulated wire. The former would be used to connect the siege head-quarters with those of the head-quarter staiF, and also for such portions of the line from the siege head-quarters to the advanced works, as are not much exposed, and where an aerial line is admissible ; beyond this the insulated wire is laid, if possible, on, or when absolutely necessary, under the ground, in rear of the trenches and ap- ])roaches. If deeply buried, it is hard to find out and repair faults, &c. The failure of an aerial line, as compared with a ground one, was shown at Paris in 1870, when the French had a double system, connecting the forts and advanced works with head-quarters. A few days' firing so disabled the aerial line, that the attempt to maintain it was abandoned. In the Crimea we used about eighteen miles of telegraph, with seven or eight stations, the chief ones being at Balaclava, the head-quarters, and the engineer park of the left attack. The line was buried eighteen inches under ground. The Americans, in I860, brought their lines as far as the second parallel before Fort Wagner ; and we learn from Tiedemann that, at Strassburg, in 1870, the Germans carried the field telegraph as far as the third parallel, whence, by means of a captured countermine gallery, they observed and telegraphed back the effects of the curved fire against a scarp of lunette 53. Before Paris, at the head-quarters of the invader, military telegraphy received its largest development (pi. i.); and at the second siege, the assailants carried their telegraph into the advanced trenches, before the Point du Jour, whence the fire of the advanced batteries, and of those at Montretout, was regulated by obser- vation, and that of the latter stopped as the troops entered. As an addition to the telegraph, or as a substitute 38 THE ATTACK OF FORTRESSES for it, visual signals may be usefully employed at a siege ; in the daytime by means of flags, and at night, by hand-lamps and lime-lights. Of the latter, 36 are provided in our siege equipment for each army corps.^ Electric lights, to illuminate the ground over which night attacks may advance, are likely to form part of the siege equipment ; and they may, in such case, be available also for signalling ; but, hitherto, they have not effected much in the way of illumina- tion; and as the machinery^ for each light weighs nearly a ton, and requires an engine of 6 horse-power, their use is more within the power of the defence, than the attack. In any case there is nothing to show that the latter is likely either to gain or suffer much by their use at ranges exceeding 800 to 1,200 yards in favourable weather, and at less ranges in mist or fog ; though their employment by the defence, in the latter stages of its resistance, in combination Avith light balls, rockets, and parachute lights, will, not a little, increase the difliculties of the assailants. COMPOSITION OF THi: SIEGE TRAINS. Before discussing the ends to be attained by the different siege works, we have to consider the ma- terial means, viz., the artillery and engineer siege * "At Sebastopol, the Russians employed Cossacks with flags to regu- late their indirect fire against bodies of the allied troops ; while at the siege of Belfort in 1870, the Germans arranged a system of signals with flags and with the electric light. Visual signals were largely used in the same war by the Second German Army Corps before Paris." — GCETZE. '^ The Gramme and Siemens dynamo-electric machines promise best at present. The intensity of the ray can be somewhat increased by diminishing its spread ; but, to secure searching power, a horizontal s])read of 15 degrees and a vertical spread of 5 degTees seem desirable. The observing or shooting parties should be placed well to one flank of the light, which should be capable of being shifted. The electric light due to a large Groves' battery, which is more portable than the steam arrangement, will show troops at night at a distance of 500 yards. IN THE FUTURE. 39 trains. On the complete organization and provision of these, depend, in great measnre, the quickness with which the assailant can strike the defender at a dis- advantage. To what we lost in the Crimea for want of this, we need not refer; but even in 1870, the preparations for the siege of Strassburg, were so retarded, as to cause no little delay in beginning.^ The strength of a siege train for any one operation, Aitiii.rr siege should depend on the circumstances of the case ; and ""'""• the artillery train should, by Avay of providing for contingencies,^ have 10 or 15 per cent, more guns than can be employed at any one time. In most countries it is customary to decide on a unit of siege train, several of which go to form the train; the unit itself being composed of the different natures, in the proportions thought best. At present we have a heavy and a light siege train unit, the former to con- sist of eight 64:-pounders, eight 40-pounders, and fourteen 8-in. rilled howitzers ; the latter, of ten 40-pounders, ten 6'3-inch rifled howitzers, and teu 25-pounders, all M.L.R. The arrangement is con- venient for small sieges, where only the hghter guns would be wanted ; but for large operations, all the natures would be required; and in considering the proportions, we shall assume that the two units are combined. These proportions depend on the different functions the guns have to perform, viz. : — 1st. To repel sorties. 2nd. By means of direct fire, to bombard distant works; to dismount guns; to pierce and cut down traverses ; to enfilade unprotected lines ; and, occasion- ally, to destroy iron-plated defences. 3rd. By means of curved or high angle fire, to search out the interiors of works; to enfilade the parts provided with traverses ; to demolish blindages, magazines, and parados; and to breach escarps, caponieres, &c. 4th. In the advanced stages of the attack, to keep 1 "Revue d'Artillerie," viii., p. 386. 2 Wolff mentions (pp. 408-411) that 55 German guns and 7 car- riages broke down after an average of 800 to 1,300 rounds; but the French tire disabled manj more carriages than guns. defence. 40 THE ATTACK OF FORTRESSES down tlie fire of the place, so as to permit of the pro- gress of the near approaches. 5th. In the close attack, to impede the defence by a continuous hail of shells dropped into the works. 6. To batter flank defences, revetments, keeps, and retrenchments at close quarters ; and to arm lodgments in captured works. Guns for For the first purpose, in addition to the field artil- lery, which will answer in most cases, a proportion of guns of the class of our 25-pounder M.L.R. is required; so as to secure a preponderance over any field batteries that may accompany a sortie. For this, too, the 64-pounder homtzer may, in some cases, be employed ; as, for instance, against vil- lages. A proportion of Gatling guns, which, in certain special cases, are valuable for the defence of positions, are also likely to be used.^ Gatling guns can be aimed with accuracy, in given directions, at night ; an advantage that the small arm does not possess : this gives them superiority over musketry lire against attacks in the dark.* For the second purpose, considerable range, great accuracy, comparatively flat trajectory, and high velocity to secure great striking power are the im- portant points. In most European siege trains, the favourite gun for this purpose seems to be the long 15-c. B.L.R. gun. The guns in our service, which most nearly correspond with this, are the 64-pounder M.L.R. of 64 cwt., and the 40-pounder M.L.R., the one rather a heavier, and the other rather a lighter, gun. Under this head we have to consider a more ^ " Thus the Bavarians used theu' mitrailleurs, for the defence of tlieir part of the hue of investment hefore Paris in 1870-71." — GaiTZE. 2 The full value of Gatling guns will not be felt until thej are made more portahU than the lightest cannon ; less complicated than at present; and capable of firing the small arm cartridges. The weight of the small service Gatling is more than twice that of a gun tiring an 11 -lb. shell ; and too much is sacrificed to automatic action and quick firing A Gatling gun of half the weight, mounted on light bicycle wheels, and really moveable by hand, would, surely, be a more useful weapon, even if it fired only half as fast as the present one, tied, as it is, to a heavy gun-carriage and weighing altogether over a ton. Guns for direct fire, IN THE FUTURE. 41 ])()W(jrfiil class of gun, not included in our siege train, but which, either our necessities, or op[)ortunities, may lead us to use. Although land fortresses are not rich in iron defences, we may, particularly in operations on the coast, have to deal with arniour- l)]ated works/ Against very light i)hiting, we might employ the 64-pounder of the siege train, with its excellent battering shell of 90 lbs. ; and when this would be insufficient, w^e might, now and then, bring up the 7-in. gun of 90 cwt., adapted for siege pur- ])oses ; or else draw on the navy for their 7-in. and 8-in. guns, which pierce about 9 and 9^ inches of iron. These we should bring into battery on rails if possible; though, even without such aids, the Americans, in 18 63, brought IT 5-ton guns into battery before Charleston under very difficult con- ditions. As there is no need to resort to guns of this weight for high angle or vertical fire, because rifled howitzers, throwing as large shells, are much more portable ;^ we may assume that they will rarely be used, except for the work that they alone can do, namely, the destruction of armour or of very massive masonry. Hence, their object being defined, they will require but little training ; their fire, how- ever, must be direct, and their range short, say 1,000 to 1,500 yards, a fact that further restricts their use. For the third purpose the qualifications are, a Guns for small limit of error at long ranges and very high curved fire, angles, and at shorter ranges, with angles of eleva- tion less than 20°, a uniform trajectory, extreme ac- curacy, and considerable final velocity. In our ser- vice, the pieces we should expect to see used for the purpose, are the 8-in. and 6'o-in. K. howitzers: of the capabilities of the latter it would be premature to speak, but, should it not prove efficient in these * Metz is being provided with a few turrets, plated with about 6 inches of iron. Antwerp has also some iron defences. At short ranges, the battering shell of our G4-pounder would pierce 6 inches of iron ; and repeated blows would destroy even a greater thickness. ^ Thus the 10-in. R. howitzer of 6 tons, throws a sliell of 350 lbs. ; "while the Palliser shell of the 8-in. gun of 9 tons weighs only 181 "5 lbs. : the same almost as that of the 8-in. howitzer of 4(5 cwt. 42 THE ATTACK UF FOKTKESSES respects, it is not too much to say that our train will be wanting in one very important and necessary ele- ment. On the Continent the gun most commonly used is the short 15-c. B.L. gun, the excellent quali- ties of which, have been fully tested, both by ex- periment and in the war of 1870-71. This gun can be fired Avith a shell of 2^ calibres, and also with the shell of the long 15-c. gun: an advantage not pos- sessed by M.L. guns of the same bore, but Avith a different twist, on account of the dift'erence in the positions of the studs.' The 21-c. B.L. mortar, which is fired fi'om a bed, not a carriage, is also much used on the Continent, and corresponds in calibre with our 8-inch howitzer ; though the latter is more of a shell-gun than a mortar. It is chiefly used for tiring at high angles, against the roofs of casemates, &c., when great penetration is required, and for breach- ing. To supplement guns of this class, 8 in. and 10-in, smooth-bore mortars may also be used. ].ight trench For the fourth purpose extreme mobility, flat tra- ^""^' jectory, and a moderate destructive power are the qualities required. Future experience may show that the heavy Catling guns of 0"65-in. bore, such as are adopted in Russia, are suitable; but, in the absence of experience, we incline to the belief that very light shell-guns (as light even as the 7-pounder or 9- pounder M.L.R. guns, so as to have extreme mobihty) will, combined with the use of portable Catlings and Wall pieces. Wall picccs j^rovc most eftective. To these guns we shall have occasion to refer further on ; but on the subject of wall pieces we may remark that, having a mobility not much inferior to that of a small arm, they can be used when nothing on wheels can be employed. They can be shifted from place to place, almost as quickly as, and attract no more attention than, a musket. At the same time, the weapon being " nobody's child," has, except in Prussia, almost dropped out of use. The artillery make it, and bring it up with their trains ; the infantry shoot with it, but do not like the clumsy thing; while the engineers, ^ Tlie use of a gas cheek, however, now promises to do away with the necessity for studs. IN THE FUTURE. 43 who never handle it, derive the most benefit from its use. Hence, though its value is not denied, and its introduction has been urged by soldiers of great ex- perience ; ^ it is plain that, useful as it is, nothing but the exercise of the highest authority can bring it into the service. Of its use we have not a little evidence from the war of 1870-71. The most remarkable fea- ture of the siege of Strassburg, was the way in which the light 9-c. siege guns, on high carriages, and the wall pieces in the hands of infantry detachments, completely silenced the fire of the place. At Belfort too, wall pieces were used in the attack of the " Perches," though with less marked success. They also formed part of the artillery siege train brought up against Paris. ^ The best argument in their favour is, however, the fact that, in the new Prussian siege train, the proportion of wall pieces to guns and mortars is as three to eight.^ The conditions that a wall piece has to fulfil Conditions. are : — 1st. To have a greater penetration, and a some- what greater eftective range than the small arm, 2nd. To be fit to fire from the shoulder without a stand, when rested, as it would be, on a bank or parapet. 3rd. To be handy, and easily moved and loaded. 1 Cf. " The Military Opinions of Sir J, Burgojne," p. 304. ■■^ Gffitze (p. 186) mentions that they enabled the Germans to drive the French out of part of Lcs Moulineaux, south of Paris. •■' The present pattern of German wall piece, which is about to be improved, and adapted for a solid cartridge, is a B.L. on the Ziind- nadel-o-ewehr principle; barrel cast steel; length, 39'44 in. ; bore, 0-928 in. ; twist, one complete turn in the length ; bullet, cast iron or steel, 2-08 in. long, weight, 3 oz. ; charge, O'To oz. ; weight of piece, 62 lbs. These pierce a gabion filled with earth, and go through two feet of sand-bag parapet at 250 to 300 paces : the bullets often break up. The wall pieces we took at Bomersund, in 1854, were B.L. pieces weighing 23-5 lbs. ; length of barrel, 42-5 in, ; weight of conical bullets, 4 oz. ; diameter of bore, 0-875 in. ; they were fitted with a swivel pin intended for a socket. The Austrian B.L. wall piece, weighing 15 lbs., is effective up to 1,300 yards ; it is furnished with a tripod ; and its bullet weighs 3-3 oz. — See " Bevue (VArtiUerie," July, 1874. 44 THE ATTACK OV FORTRESSES For the first, Sir John Burgoyne suggested a penetration, greater than that of the small arm by one-third or a quarter. In any case mobiUty should be the first consideration, when a penetration double that of the musket is secured. The requirements for penetration are, a high velocity, and a hard tough bullet of the greatest weight that the shoulder will stand. ^ The size, and weight of the piece, will insure a somewhat greater eftective range than that of the musket, and experiment may show that telescopic sights would be a gain; as, even with small bores, the Confederates used telescopes with success at Charleston.^ For the second, the recoil must be such as a man can stand. Hence a very light gun is not likely to answer. There are several ways of diminishing the recoil, for instance, the employment of india-rubber or spring-heel plates; the use of an unenlarged chamber ; and the removal of the rifling for some dis- tance from the chamber: but even with these, it does not seem likely, that a bullet of over three or four ounces will be convenient.^ If a stand, or tripod, have to be used, the piece is unfit for shallow rifle pits or other low cover, and wants more space, and is less mobile than without one. At the same time, a ball-joint with a spike to be stuck into the earth might, if fixed to the piece, help to check recoil, and would not be in the way. For the third, the weight of the piece must not be too heavy for a man to carry, i.e.^ should not, if possible, exceed 30 and in no case 50 lbs. The • The experiments of Whitworth have shown that, for hard bullets, a mild powder is preferable. With hardened steel bullets (fig. 19) of 472 grains and 85 grains of powder, he pierced i-in. wrought iron plates at angles of 45 degs. : a fact that suggests the advantage of liaving, for siege purposes, a proportion of steel-headed bullets for the small arm, to be employed against the bullet-proof shields of -i-in. steel, which will now be so much used. With hard metal bullets, the twist can be given by a gas check. 2 Gillmore, p. 139. ' As by the Declaration of 1868, the smallest explosive bullet must exceed about 14 oz. (400 grammes); the wall-piece bullet, in Europe, at least, must be non-explosive. Pirce« to pro- mortars. IN THE FUTUKE. 45 barrel should not be extremely long, and should be breech-loading, with a simple side or top action. We next consider the fifth class of ordnance, be- tween which, and the others there is this difference, due- surface that, while these latter are chiefly employed against ' "'" the defences, and, in most cases, depend for their effect on their penetration before bursting ; those of the fifth class, are employed against the defenders, and their bursting effect is diminished by their penetration. While, therefore, they must be handy and easily moved about ; what they have to do is, to throw shells, with large bursters, for a few hundred yards, at high angles, and with just enough velocity to secure fair accuracy. Hence it is for the artillery to consider whether a light rifled mortar will, or will Li^i.t riflpd not fulfil these conditions better than small wrought iron or steel S.B. mortars of the same weight.^ The existing 7-pounder, throwing an 11-lb. double shell, is to be thus used on a light mortar-bed. It is so light, it can be shifted by hand. If, on this subject, we may venture beyond the limit of what is, we imagine that one form of the mortar of the future, will be a piece in which extreme lightness is secured, by designing it to be fired with the lowest charge which will just carry a very large shell (perhaps of wrought iron) at most 300 or 400 yards, and with the lowest practicable velocity. Under such conditions the Aveight might surely be small, when we remember that Mallet's built-up mortar threw a shell of 2,G60 lbs. a distance of 2,700 yards. For the sixth class, guns such as the 25-pounder M.L.R., or the 9 and 12-c. B.L.R. are suitable, ,'.>Mi^)^iM, Battekt 30, Strassrurg, 1870—71. (■ IN THE FUTURE. 41) The first of these facts was proved by our ex- perience and that of the Russians in tlie Crimea in 1854-55. Todlcben, in his account of the defence, mentions that on the 17th of June the allied fire destroyed 200 of his embrasures. In the war of 1870-71 the French found great difficulty with many of their embrasures, which were destroyed by guns they could not reply to. Thus, at Belfort, they had 16 per cent, of their pieces, and 32 per cent, of their carriages disabled; while their fire only destroyed two German guns and seven carriages.^ During the second siege of Paris, they cut embra- sures in the German battery No. vii. at Chatillon : the use to which the battery was put, was, in each case, identical, namely, to counterbatter Fort Issy, which lay 60 metres below ;^ and the Communists there caused the French much greater losses than they had inflicted on the Germans; while, as regards defence, the embrasures of their works were everywhere com- pletely wrecked. After the second siege, while the parapets of the enceinte of Paris were but little in- jured, and the excellent blindages mostly intact, the guns in embrasures were reduced to the state of lumps of metal in a heap of splinters. The diminution of lateral range due to embrasures often prevents the use of the siege guns for resisting sorties, and necessitates the making of otherwise unnecessary batteries. Even when embrasures are made with small splay, the parapets are weakened for several feet on each side of the throat; and the part so weakened gives little or no protection, so that, against fire directed on the embrasure, the gun is as much exposed, as in the overbank arrangement, and the detachment moi-e so. The blast of explosion alone, in time, destroys embrasures, and their revetment is apt to take fire. Officers, who were in Fort Issy in 1870, mentioned that they had every night to keep strong working parties engaged at making good their own damages : at Montrouge two hundred men were often employed for this purpose in a night. Lastly, 1 Wolff, pp. 408-411. 2 P. P. K. E., vol. XX., p. 22. E 50 THE ATTACK OF FORTRESSES embrasures complicate and delay the construction of a battery, in which, whether there be embrasures or not, the same reUef is necessary : they also require extra materials/ It is true that, though the embrasures may be shut up, still the parapets between them protect the guns from oblique fire : but, admitting that it is more im- portant for guns to be able to fire, than to be safe from Their disuse, fire, it appears a necessity that siege carriages, while kept, as regards their height, within the limits of stability, should, for the future, be such as to allow guns to fire overbank when directly opposed to the defensive artillery. In such cases, except with dis- appearing carriages, shallow unrevetted embrasures with a counterslope will be used ; the extra exposure of the guns to enfilade being guarded against by choosing suitable positions for the batteries, or by high screens or traverses. Deep embrasures, in spite of their defects, may still be desirable in special cases, those, for instance, in which guns are exposed to a cross-fire alone ; or where they are only exposed to indirect fire. In these cases, raised masses between the guns give some protection. Transport of A Collateral question, important in its bearing on guns. ^j^g length and bulk of the train, and on the num- ber of teams it requires is, whether the heavier guns should have separate travelling and fighting carriages. The whole of the guns in the German siege train, as well as our own, travel on the firing carriages. The arrangement is convenient; but it appears a question whether, on the whole, weight would not be saved, and recoil rendered more ma- nageable, in the case of the heaviest guns (the 64 pr. and 8-in. howitzer), by using sliding carriages and ^ Were further evidence wanted, the late Russian experiments sup- ply it. Guns were fired at, at 1,160 yards, and were mounted as follows: — 1st, so as to fire through a deep embrasure. 2ud, so as to fire exposed " overbank." 3rd, so as to fire " overbank," through shallow embrasures. To dismount them, the number of shots required were ; for the first, 10 ; for the second, 26 ; for the third, an average of 63 to 64, — Revue d'Artillerie, January, 1877, pp. 343-4. I IN THE FUTURE. 51 naval slides or directing bars ; rather than fire such heavy pieces off carriages with wheels and axles. Next to the question of the carriages comes that Proportions of of the ammunition. A reference to the table will ""l'""'■''''"''• show that the average weight of our siege shells is very high, owing chiefly to the large proportion of 8-in. rifled howitzers. This is, doubtless, an ad- vantage if we can get up the shells ; but it throws a considerable strain on our transport. As to the number of rounds to be kept in peace time ; seeing that our manufacturing power at least equals that of the rest of Europe, the proportion laid down, viz. 500 rounds, ought to be enough. It should be understood, however, that, for war, a larger num- ber will be required. Hohenlohe tells us that in 1870-71 the reserve store of shells in the park before Paris, varied from 300 to 500 rounds per gun; while 1,000 rounds were thought necessary for the siege. ^ At any rate, the siege cannot be commenced without having 400 or 500 rounds per gun on the spot, Avith a certainty of the supply being kept up; the total supply being, according to B runner, about 1,500 rounds for each gun; 600 to 800 for heavy, and 1,200 for light mortars. As to the number of rounds a day, Hohenlohe states Daily supply. that 50 or 60 per gun was not often exceeded. As a rule, the Germans seldom fired over eight rounds during any single hour in daylight, generally not more than three or four, and fewer at night; as they found, no doubt, that to shoot straight^ one must shoot steady; and, further, they had to nurse their breech-loaders, which cannot be fired continuously at the same rate as muzzle-loaders ; besides which, the firing is now much more regulated b}^ observation, M^hich involves delay. The quantity of ammunition, too, that can be spared for each day, has become a more serious question. In certain cases, where time does not press, and construction is easy, magazines for two or three days' supply may be made, if the site be a secure ' Goetze. 52 THE ATTACK OF FORTRESSES one : but, as a rule, room for a supply for twenty- four hours can, alone, be allowed. At the first batteries, where the makmg and supply of maga- zhies is easy, there should be room for 160 rounds ; the greatest number required being, probably, 72 rounds for the first six or seven hours, and the same for the remainder of the twenty-four. Breaching bat- teries, for direct fire, might, possibly, require the same accommodation : while those for curved fire would use, at most, 8 rounds for each hour of the day, and 3 at night : for these, 140 rounds might be provided. For other purposes a smaller supply would sufiice. It seems reasonable, therefore, to reckon on having to provide for not more than 100 to 160 rounds per gun, for twenty-four hours' supply, in the battery magazines. This will lessen the size of the magazines, which we have, for some years past, been making for 380 rounds per gun; or for 20 per hour in the day, and for 10 per hour in the night. Composition of The compositiou of the engineer siege train is Sr" "'°^ based on the gun unit, which was, till lately, one of - thirty-five guns. It may now be necessary that the train shOuld be composed, with reference both to the light and to the double unit, supposing the latter to be employed for large sieges. In considering the composition of the engineer train, we must distin- guish between siege luxuries and siege necessities} To the former class belong trench railways and engines, steam apparatus for electric lights, and, in some cases, iron-band gabions. Thus, when we can get brush- wood, it is evidently unwise to carry a ton^ of gabion- bands for each gun of a train of 200 or 300. Nor can we always reckon on bringing up the machinery to be worked by steam sappers, even though the latter can transport themselves. Among the necessities, however, we must consider — in addition to the cut- ting and intrenching tools — the materials for the field telegraph, and, in certain cases, the means for the de- ^ The lists should show these separately ; and in all cases weights, volumes, and tonnage should be stated. ' 1,000 bands per gun is the number laid down ; these weigh a ton. I IN THE FUTURE. 53 molition and repair of railways; for the supply of water, and for the driving and ventilation of mines ; as well as the explosives and ap[)aratus for firing mines/ Again, supplies of timber for platforms, &c., may be necessities in some cases, while not in others, and so with the proportion of cutting tools. In the case of intrenching tools, the proportions must be based, not only on the largest number likely to be required, but also on their relative durability under the circumstances : for instance, shovels break down much sooner than pickaxes. DUTIES OF TROOPS AT SIEGES. In our service there is an urgent want of distinct and authoritative regulations on the duties of troops at sieges, such as exist in other armies. The duties of the troops are, either to work themselves, or to cover the workers. The sappers at a siege are, of course, too few to do the work, Avhich must therefore be carried out chiefly by infantry. The main infantry working parties are demanded at head-quarters early each day, for the next day, by the Commanding Royal Engineer ; and ordered in the orders for the day, in which also appears the detail of the covering parties, under the orders of a general for the day. In cases of emergency, it is necessary that small working parties should be obtainable from this general, on the demand of the Engineer Staff in the trenches. As to what can be done, it is generally agreed that Workin men can be employed for one day as covering troops, p"*'^"- and on the next at work, leaving the third for rest ; and, further, it is found that a man can do all he is capable of doing in one relief, in about five hours.^ In ^ A secure means of ligliting Bickford's fuse is much required ; also a good supply of tracing and other lanterns for work at night, as work will now, more often, be carried on under circumstances that per- mit the use of lanterns : our siege equipment only provides about lUO. 2 In the '■ Military Opinions of Sir J. Burgoyne " we find short reliefs of six hours strongly advocated ; and, to quote an older opinion, 54 THE ATTACK OF FORTRESSES Short reliefs. Covering troops. Strength of besieging force. this time, untrained men at two paces apart — the most convenient interval — can excavate 80to lOOcubic feet. Hence when reliefs can be changed without risk, short periods seem best; the men being all tasked and marched off when done. Above all things the system of detachments is to be avoided. As a rule, the working parties, under their own officers, parade by companies or battahons ; without belts, with rifles slung, bayonets fixed, a few cartridges in their pockets, and with filled water-bottles ; without the latter, thirst may stop the work. They assemble at the inter- mediate dep6ts, where they get tools and instructions, and are conducted to, and started at, the work by the engineers. Previous to work, whenever time permits, men should have some practice at extending along a traced line, or on a traced battery, at the park ; or at their cantonments if it save them fatigue. The earliest siege works will be protected by the outpost line of the investment ; but as the works pro- trude beyond this line, special troops are required to cover and protect them. The formation of the covering parties is, in general, a chain of double sentries, with supports, and main body or reserve in front of the work that is being done. As a rule the double sentiies should have, between them, a light pick and shovel, of which each battahon has 150 sets. Thus one man can always be getting cover, while the other keeps a look out. The covering parties are, of course, chiefly infantry ; cavalry, with field guns, may be in reserve, under cover, on the flanks. The strength of the force required to supply the working and covering troops, is generally reckoned with a view to its furnishing three reliefs, each equal to the probable field force of the garrison.^ But from Marshal Saxe says, " The soldier who only works three hours a day does his business cheerfully, and is able to stick close to it." In the long winter nights before Paris in 1870, the Germans sometimes em- ployed as many as four reliefs. 1 Estimated by Brunner at two-thirds the garrison. Brunner sug- gests that the force to supply the covering troops should be two and a-quarter times, and that the army of investment be three times the strength of the garrison. IN THE FUTURE. 55 what we have already pointed out as to the effects on the attack, of the size of the fortress; it is plain that, in proportion as the fortress and its garrison are large, the strength of the covering reliefs may be relatively smaller. Bearing in mind that in 1854 we besieged Sebastopol with a force inferior to the gar- rison; and considering the retaining power of the new arms — as proved by the war of 1870-71 — as well as the certainty of support from the investing troops on the flanks ; it is thought that three reliefs, each of one-third to two-thirds the garrison, will in most cases suffice as siege troops ; while a force of one and a-half to two and a-half times the garrison will be capable of conducting both siege and investment according to the greater or lesser size of the for- tress; particularly if the garrison, as must usually be the case, be composed of inferior troops. The siege of Belfort^ is a remarkable example of what can be done in this way. The investment, at first conducted on a circumference of twenty-five, and afterwards of eighteen miles, was effected by 8,000 infantry with the usual proportions of the other arms — a force only half that of the garrison — nor did the siege corps at any time exceed twice the strength of the latter. When we come to consider the actual conduct of First siege a siege now-a-days, we are at once met by a new operations. feature which the besieger has to face. In discuss- ing the subject of the investment, we saw that the progress of the assailant is barred, at a considerable distance from the fortress, by the power of the de- fensive artillery. This distance is generally too great for the effective beginning of the siege proper; so that the attack is obliged to use its siege guns at long ranges, to subdue the fire of the defenders' advanced posts and permanent works; and thereby to secure an advance on the place to within besieging distance, along the region selected for the operation. This was notably the case with the advanced villages and woods occupied by the French outside of Behbrt in 1870-71, which had thus to be bombarded by the ' Wolff, p. 415. 56 THE ATTACK OF FORTRESSES German siege guns, before they could be captured. Hence it is plainly of importance to occupy com- manding positions for the line of investment enclosing this region, and for the first artillery positions. These will enable the investing troops, along the front of attack, to advance with the help of their field guns ; and to win some more ground from the defenders than elsewhere ; and so to throw forward their shoot- ing line, as to cover the first artillery position. First artillery The posltious for first battcrics will, according to position. Hohenlohe, be at from 2,000 to 3,300 yards from the heavy guns of the defence : distances, we may observe, which were in some cases nearly doubled before Paris in 1870-71. It must be clearly understood that, from the first, " forward " should be the watchword of the attack ; and the works, whether of the investment or of the siege, should always be advanced as far as they can be without great risk : at the same time we have to consider what is probable^ rather than what may be possible ; thus we find that Brunner puts the limits of the first artillery position at from 2,000 to 4,000 yards, and recommends a preponderance of three guns to two ; assuming that the defence can mount a gun to every fifteen yards of front bearing on the attack. At Sebastopol in 1855, the preponderance, as given in Todleben's account, was the other way ; in our first bombardment on the 9th of April, 1855, we opened fire with 444 guns; the Russians, according to him, with 466. Fortresses do not, however, often have a fleet and arsenal to arm from ; nor, as in this case, a gar- rison of 70,000 men to oppose to an investing force of 60,000. On the whole, even with improved shooting, the difiiculties of observation will in general limit the distance of the first batteries to about two miles from the permanent defences. The great depth of this belt (about three-quarters of a mile, to a mile) gives a very wide choice in placing the batteries — these, as regards their sites, may l)c classified as : — 1. Those which are to be made behind permanent cover, over which they are to fire by observation only, with the help of scales. IN THE FUTURE. 57 2. Those which are made behind existing and re- movable cover, and unmasked when required. 3. Those which have to be made in the open, and can only be covered artificially. Of the 500 batteries said to have been thrown up in the war of 1870-71, the majority were made out of sight and unmasked; a proportion were formed behind permanent cover ; very few indeed were thrown up in the opert. The new power of firing accurately by observation with directing scales, not only makes night firing more effective, but also renders concealment more easy; and yet, though in the war of 1870-71 the attack reaped great benefit by first using the method of firing from unseen positions, we have indications that, for the future, it must share this advantage with the defence. Thus, at Paris, the Germans entirely failed to silence the French mortar battery behind the embankment (thirty feet high) at the Issy Station ; while at Belfort the method was still further used by firing over the citadel, over traverses, and from interior spaces over a distant parapet: this fii'e the German guns quite failed to subdue. Further we learn that Brialmont now proposes a " batterie basse " in his large works, consisting of a straight retrenched parapet at the gorge, parallel to, and with a crest three feet below, the crest of the front. From this unseen position it is intended to direct a powerful, high angle fire over the front attacked (fig. 40, pi. xxi.) from guns unseen by the assailant. It is believed that the bare nature of the site of our operations in the Crimea, coupled with the former inaccuracy of curved fire, has lor years in- clined us to forget that natural cover is generally available ; and the more so the further we are from the fortress ; owing both to the wider choice, and to the difficulty of clearing within a great distance from it. Hence it will almost always be possible to choose sites screened by woods, walls, &c., the fronts of which can be quickly cleared, if necessary, for direct fire, or else to suit the required elevation. The following situations should also be sought, viz. : — 58 THE ATTACK OF FORTRESSES Choice of sites. Sheltered positions. Approaches. 1st. Those which, from the trace of the defences, are not much exposed to cross fire, and which will be concealed by collateral objects from enfilade fire, and are easily supported. 2nd. Those where the background, as well as objects in front, are in favour of concealment. 3rd. Those near roads suitable for bringing up the guns, &c., or where the ground is passable for them. 4th. Those where the soil is not likely to give trouble by its wetness or hardness, and where undu- lations and slopes may be turned to account to diminish labour and aid drainage. 5th. Those with a command over the place. The positions of the German batteries south of Paris in 1870-71 illustrate the first; thus the first batteries 2, 3, and 4 (pi. viii.) lay so, that, owing to the trace of the forts, and the restrictions caused by embrasures, only a few French guns could be brought to bear upon them; while the French brought such a cross fire on Nos. 5 and 6 that they had to be disarmed ; elsewhere many of the batteries, those for instance between Bagneux and Cachan, were so covered by woods, &c., on the flanks that they were but little exposed to enfilade fire, while those at Chatillon were so screened by trees, that lines of sight had to be cut through them, in order to fire.^ Again, the position of the Versaillist batteries at Montretout in 1871, made them hard to hit; as the ground rose a little behind them, while the tops of some trees in front, were just enough cut away for sighting the guns. At Strassburg, also, many of the batteries were hardly visible behind the slight undulations that concealed them. The approaches too play an important part : thus, some of the commanding positions round Bitche could not be used in 1870-71, for want of roads, and because of the difiiculties of the country. Again, the difiiculties of construction are often 1 Gcetze, p. 124. m \ k if"^ / //^ Plate Vlll #*^. \/ -r4\>--M' //.V" / r reAifny-Aijx rb'ses i \ \7> '>^^' IN THE FUTURE. 59 considerable. Those due to the rocky nature of the soil have already been referred to ; and, in making the batteries before Delhi in 1857, fascines had to be used for want of earth. At the siege of Charleston in 1863, batteries in the marshes had to be floated on timber grillages; while in 1870-71, the sites chosen were mostly on high ground, and the wider area of choice, on the whole, diminished the difficulties. Sites in woods or among buildings are also trouble- some ; but when the spot is important, these difficul- ties, and those of drainage, can be got over in the case of batteries made out of sight. Exposed sites should be so chosen, as to insure completion in a given time. In all cases the best engineering is to do the work with the least labour. As to command, one great feature of the sieges in Commnndingr 1870-71 was that the increased range of the siege batter^s. guns, had rendered available a number of command- ing sites, till then too far off for the assailants' use.^ This simpHfied the questions of defence and drainage. The choice of sites is made jointly by the com- Building of manding officers of engineers and artillery: when bauenes! chosen, the building of the unexposed batteries, and any necessary approaches to them, are begun as soon as the tools arrive, and without waiting for the siege guns. To be able to do this is a great gain ; it saves the necessity of excessive working parties, and permits of much better work, and also prevents delays from unexpected difficulties. Thus, the blindages can be dug out to their full depth, and the timbers, rails, &c., properly placed; next, the terrepleins can be excavated, and the earth thrown on the blindages. The platforms are then laid and levelled without haste, after which the parapet is formed from the ditch, and the battery completed. From this it will Two kinds be seen that, in general, tAvo types of battery are necel^sary. wanted. The first, adapted for concealed sites, but which may afterwards be exposed to a heavy fire, should be arranged for execution in the number of rehefs that proves most economical of labour. In ' Cf. Tables, P. P. E. E., vol. xx., pp. 22-26. ^3 w ATTACK ON SOI Til 01 PARIS 1870 .rf <^W' ikcaZc (>/• 3S<^oi. IN THE FUTURE. 59 considerable. Those due to the rocky nature of the soil have already been referred to ; and, in making the batteries before Delhi in 1857, fascines had to be used for want of earth. At the siege of Charleston in 1863, batteries in the marshes had to be floated on timber grillages; while in 1870-71, the sites chosen were mostly on high ground, and the wider area of choice, on the whole, diminished the difficulties. Sites in woods or among buildings are also trouble- some ; but when the spot is important, these difficul- ties, and those of drainage, can be got over in the case of batteries made out of sight. Exposed sites should be so chosen, as to insure completion in a given time. In all cases the best engineering is to do the work with the least labour. As to command, one great feature of the sieges in CommRnding 1870-71 was that the increased range of the siege batteri°j8. guns, had rendered available a number of command- ing sites, till then too far off for the assailants' use.^ This simphfied the questions of defence and drainage. The choice of sites is made jointly by the com- Building of manding officers of engineers and artillery: when bauenes! chosen, the building of the unexposed batteries, and any necessary approaches to them, are begun as soon as the tools arrive, and without waiting for the siege guns. To be able to do this is a great gain ; it saves the necessity of excessive working parties, and permits of much better work, and also prevents delays from unexpected difficulties. Thus, the blindages can be dug out to theu' full depth, and the timbers, rails, &c., properly placed; next, the terrepleins can be excavated, and the earth thrown on the blindages. The platforms are then laid and levelled without haste, after which the parapet is formed from the ditch, and the battery completed. From this it mil Two kinds be seen that, in general, two types of battery are nece'lsary. wanted. The first, adapted for concealed sites, but which may afterwards be exposed to a heavy fire, should be arranged for execution in the number of reliefs that proves most economical of labour. In • Cf. Tables, P. P. R. E., vol. xx., pp. 22-26. 60 THE ATTACK OF FORTRESSES such cases, parapets up to 30 feet thick may be pro- vided, and such a thickness given to the earth roofs, as will render them secure. The second kind of battery, a number of which may have to be made on the same night, should be of such dimensions as can, with certainty, be thrown up in two short reliefs^ (leaving room for future improvements); and can be executed with a moderate number of men. These batteries are intended for sites exposed to the defen- der's fire, particularly in the second artillery position ; but they will also, if their earth roofs be thickened, answer quite well enough for most of the guns of the first artillery position. Requirements Xhe general requirements of a battery are : — of a battery. -.a • i 1st. A covermg parapet and traverses; a screen, if exposed ; a bomb-proof magazine having sheltered communication with the battery ; bomb-proof, or at least splinter-proof cover for the detachments ; ramps of descent for the guns ; a space to store the loaded shells; a small observatory in the parapet for a " look-out," and a raised one for each group of bat- teries; and for those in, or just in rear of a parallel, covered communication behind them. It is, of course, understood as an invariable rule, that all the batteries of the position must open together. Hence, as the few batteries that must be made in the open, would be discovered in the daytime; their progress must, unless they are very distant indeed, be covered by an Artificial artificial screen, or else they must be begun and finished screens. -^^ ^^^ night. Artificial screens of branches, trans- planted hedges, fascine walls, &c., answer the purpose in many cases. ^ Distant works were concealed, in the war of 1870-71, by laying green branches on ^ The late Russian experiments showed that, if the range of a battery, not more than 1,150 yards distant, can be got by trial shots in the day, as many as 78 per cent, of the men working on it next night, might be hit by 20, 15 c. shrapnel shells. — llevue d'Artillerie, January, 1877, p. 346. 2 Brialmont (vol. i., p. 201) mentions experiments in Belgium, ■which show that small green branches, not over 1^ in. in diameter, do not fire percussion fuses ; and, if the leaves are off, do not hinder the laying of guns. Time fuses could be fired through even thicker I 9 RE SUITS or PRACTICE ® against a B SCREEN BATTERY I AT 1 SHOEBURYNESS 1 1869. i Total 282 Rouads. T :z:z ..,.». „,.,:!::.„ „.,.c ... r r^cH 64. P- '"(."cH eo> • • • Q -- CUBVED 1 '0 1 ■ '0 Fi^. 3, •■ # • lo' •| • II B VV; ,/?67. JVa»S«?T i mWof. i Casde.S'Jfclt IN THE FUTURE. 61 the fresh earth. This was done at the batteries between Bagneux and Cachan, south of Paris; at Soissons a similar use was made of snow. Again, we may use a continuous earth screen, Kke a parallel, long enough to make it doubtful where the battery or batteries are. This has, however, the disadvantage of disclosing the general lay of the artillery position, and, besides, adds considerably to the labour ; while we can, by careful arrangement, throw up a good battery in one night, which we cover with a short screen ; not so much to conceal the work in progress, as because experience shows that it is a most valuable protection, owing to the difficulty there is in dis- tinguishing between it and the parapet (pi. ix.). In 1870-71 the necessity of using screens was not forced on the Germans, though we learn ^ that bat- teries 6, 7, and 9, south of Paris, were provided with them. For direct fire, the screen is just high enough to let the gun be sighted over its crest, while for high angle fire, it may completely conceal the object from the battery. The usual section is a parapet with ditch and trench, revetted on the side of the battery, and distant 20 to 300 yards from its crest, as may best suit the ground and aid concealment; the greater distances being generally the more eff"ective ; and herein lies, as we think, an advantage the attack is likely to retain; for though the prin- ciple be adopted by the defence of concealing bat- teries within the works; the small depth of the works causes the positions of such batteries to be known within a little. In this respect the attack is much less limited, so that the defence will have relatively much greater difiiculty in judging of the positions of unseen batteries. One disadvantage of curved fire regulated by scales and observation is, that it is too slow for use against troops moving in the open ; in which case, guns must be fired by sight. In considering this function of the siege artillery, we have to remember, that the capacity for a wide sweep of ground is chiefly im- 1 Goetze, p. 174. 62 THE ATTACK OF FORTRESSES portant in the batteries of the first position ; because, at the stage when those of the second position are formed, sorties will be met most successfully by the musketry fire of the parallels, and the artillery fire of the first batteries supported by field and Gatling guns. On the other hand, the chief value of the screen is felt in the exposed batteries of the second position, where it will constantly be a necessity; while in those of the first, it may be dispensed with where it might impede the general action of the guns; this inconvenience in its use might be further diminished were the fore-sight on siege guns made so as to be raised and lowered, as well as the back-sight. For example, in the 64-pounder gun, the line of sight is 14 inches above the axis at the trunnions; accordingly, the gun can be sighted over a screen which just conceals it from the object; while the screen can always be placed so far forward, as to be cleared by a shell fired with any elevation. Thus, a shell fired with an elevation of 2 degs., would pass a foot above a screen placed 60 feet for- ward, and the crest of which was a foot above the Raised sights, axis (fig. 23, pi. XX.). If, now, the sights could be each raised a foot, we could either employ a screen one foot higher, thus getting more cover; or, with the first screen, lay the gun on ground which, with the lower sight, would have been concealed by it. In fact, so great is the power of concealment which this method permits, even with direct fire, that, except where much depression is required, the whole of the assailants' guns, and indeed those of the de- fence, might be laid by sight, and yet be unseen from the front. This advantage will be much felt in pre- paring for the special battering guns already referred to, both on account of their having to fire direct, and because of the labour of making their emplacements, &c. In such cases, earth screens will act as blinds while the work goes on, and will afterAvards conceal the guns themselves. One-night The general arrangement of a one-night battery is battery. indicated in pi. x. The first step towards getting N.B. If 75 workmav per gurv be. not avcuZaydle /or th£. onjt. TtMQ?tt' bcUZertes the. parapeis may be. redMx:ed- to iW f^ /romy Z7 f^ & the. ifUervals iram/ 5Z to 36 f&e^. TABLE OF MEN REQUIRED, l?T RELIEF. w.c.o? Tu^Jos Dufae,rs Slwvelhrs Total 2. Tironi. Ditch 4-0 36 76 1 Riyht' GuMyPortton an/iJRourqj. 18 6 114 1 Lehy do. do- 18 6 24 1 Shi Iters 14 14 1 .liecir Tre.Tich- Z4 1Z 36 ^ JctnJ. 114 60 174 1 2''^ REL lEF. i % Jront Dvf/Ji^' 4-5 30 75 1 Guft Portion 19. i rz Shelt^^s SJSfirter's 8 Hear Trenrh 24- 1Z 36 3 TotxiL 83 4% 131 Tig. 2. TASKS 1ST RELIEF. Diggers Lenqilc iBrecui-th Defyth Cont^i ts c.p*- A 4-'. 6" 1 5'. 0" 4-. 6" 10125' B 6'. ?: 3'.0' 4.6" 83' 3" C 'J . 0" 4-'-0' It -9' 9d- 0" D 1% 0" 8'. 0' r 0" 36 0" All otliers 5. d 6.(f 3. 6 105- 2^° RELIEF \ \ Diggers Xerufth Breadth DepOu Content X 6. 0- 1'- 6 3'. 6" 31'. 6 All others 5'. & 6'. 0" 1 3. 61 105. 0" Working pcurly averages 75 men/ pej^ gufi. for e4Juchy.of 2 reZieJs. tM rpp.i'.c-: J/arbetyA tf/Udj^. S.OucUSyJToUcm IN THE FUTURE. 63 a strong battery made in one night, is the arrange- ment of the diggers in the terrepleins back to back. This is further improved on, by excavating the terre- pleins to a width of 12 feet only in the first relief, after which, the laying of the platforms is done at the same time as the terrepleins are being widened. In fig. 2 the terrepleins are 3 ft. 6 in. below the sur- face, which would answer for high angle fire, or fire at a definite object ; but for direct fire, when a wide sweep is required, if the platforms be at this depth, and the guns fire over 5 ft. 6 in., the parapets before the gun portions must be kept as low as 2 ft., gradually rising to 3 ft. between the traverses. The terrepleins would then be deepened to 4 ft., or more, around the platforms, the sides of the deepened portions being carefully revetted (figs. 25 and 30, pi. xx.). In addition, the guns would be concealed by a screen, arranged on the principle already explained. This depth of 3 ft. 6 in. has been adopted, as it is a convenient limit for a single task. Platforms may now and then have to be laid on, or possibly above the surface of the ground for direct fire ; but such cases are now more rare, and cannot be dealt with in one night. On the other hand, when the ground per- mits (fig. 22), the platforms may be at 5ft. Bin. below the surface, and in special cases even deeper (fig. 20), when channels to fire through, would be cut in the solid ground. Such arrangements permit the making of excellent blindages, which might some- times even be mined out. As at the present moment our siege guns, and those on naval slides, only fire over 3 ft. 9 in., and 4 ft. 3 in. respectively; we would, rather than use revetted embrasures, put them into batteries identical with those described for high carriages, but with the relative level of the crest and platform diminished by 2 ft., and we would depend on the concealment afforded by the screen, to protect the carriages. The difficulty in making the battery (pi. x.) in two reliefs of four or five hours, chiefiy consists in the trouble it takes to get the blindages excavated in time. In the majority of cases, where the work JVa. ir 7S ma-kmen. pa- gun be not cvrculabU for dtjt' cn^ niakt- haucru^ Ae^pojyxpeta may bcrediuxd UiX^f^fivirv Ziffle tht-muryait fivm, SZ to 3e feM-. TABLE OF MEN REQUIRED. l?r RELIEF. A'o^ Ta^ka Dvqua-s a^a^s Tntal ? FTonl J>,td, 40 36 Ri.fhl Oun Ihrtum, ts * 24 1 L,.ti d.. Slow fuses. Gun-cotton. Proportions of ammunition. 84 THE ATTACK OF FORTRESSES To return to the comparison of the methods of breaching; that by demolition has the further advan- tage that the debris will not, it is found, interfere with cutting down the wall to the depth required ; while with the horizontal cut the debris may get in the way, as happened at Strassburg in 1870, at Lu- nette 53 (fig. 7, pi. xi.). Again, the masonry brought down by demolition, falls in small pieces, and gets covered by the earth of the parapet ; while by the other method it comes down in large troublesome masses, leaving any counter-arches standing, and supporting the earth (pis. xiii. and xv.) : in the demolition method these latter are pounded, as well as the wall. In all cases the earth is afterwards brought down by salvoes of shells fired with reduced charges, large powder bursters, and slow fuses. The process of breaching would be rendered more easy if means be found of having a fuse in the base of the shell. With such a fuse, the greater penetration of Palliser shells could be turned to account. A time fuse which would stand the shock of impact would be best : at present they are apt to go off on impact; and are almost sure to do so against masonry, if the velocity be high : in which case too, loaded plugged shells do the same. Gun-cotton as a burster was used with some suc- cess at Verona, in 1862. Since then the possibility of using wet compressed gun-cotton has been found out, and has rendered the use of gun-cotton for the purpose much safer; while the employment of dry cotton with the water shell shows that the proportion of dry cotton required for detonation can be used without risk. Hence it is anticipated that its employ- ment for breaching purposes is only a question of time. At Graudenz, the proportions of ammunition used with the short 15-c. gun and 21-c. mortar to make nearly similar breaches (pis. xv. and xvi.) were as 7 to 8. The heavier shells have, however, certain advan- tages already pointed out. On service the proportion would always be larger ; thus, at Strassburg, the num- IN THE FUTURE. 85 ber of rounds in the three cases we have mentioned were: 1,000 for Lunette 53; 500 for Bastion 11; and 465 for Bastion 12; and it is to be remembered that these breaches were in a very incomplete state, and would have required a good deal more hammer- ing to have made them practicable. In breaching detached walls, or caponiers, the low- Breaching de- est point of impact is fixed as Ioav as possible, and the mean point taken halfway between it and the top. It is supposed, apparently with reason, that the blow of a shell has much more effect on a detached wall than on a revetment, owing to the vibration set up in the former. As early as 1862, a detached wall at Verona was breached at 1,400 yards; the drop required having, in some cases, been as much as 17 degs. ; and we further learn ^ that the Baden guns at Kehl, in 1870, breached a part of the citadel of Strassburg at the same angle, and at a range of about 2,200 yards. The destruction of the gorge wall at Fort Vanves, in 1870, is another instance. The demolition by curved fire of unseen dams in Demolition of the defences was, for the first time, attempted at ^^'■'^^*'^^- Strassburg in 1870.^ The positions of the two most important dams, one before Curtain 15 and the other before Lunette 63, were only known approximately; and the point of impact was transferred by calcu- lation, from a visible point to the dams, the gates of Avhich were much injured, and would probably have failed under continued firing. Three 15-c. guns were used for this purpose in Battery 33, at a range of 1,950 yards, inclined to the dams at 63 and 44 degs. respectively, and with a striking angle and velocity of 7 degs. and 918 feet (pi. xvii.). In future we may expect that similar weak points will be strengthened by iron plating. We see, therefore, that with old fortresses, or in Possibilities of cases where the greatest drop need not exceed 10 llllfi'f.t'^' to 12 degs. for revetments, and 15 to 18 degs. for detached walls, breaches can, at present, be effected ' Biialmont, vol. i., p. 154. '■^ See a paper by Capt. Clarke, R. A., in " II. A. I. Proceedings/' vol. viii. 86 THE ATTACK OF FORTRESSES by curved fire with a greater or less expenditure of ammunition; though the difficulty with revetments is considerable when the striking angle exceeds 8 or 9 degs. When much greater angles of descent would be necessary, the difficulty may be overcome, either by cutting away the covering mass — which can be done by shell fire to a depth of 4 or 5 ft. — or, if this be not enough, by blowing in the counterscarp, and exposing the wall or caponier. As to the future, bearing in mind the facilities given by the demolition method, and the probability of greatly increased effects from the use of gun- cotton and of improved fuses, it is to be expected that breaching will become generally practicable, unless the lower half of the wall is more than 4 ft. below a line of fire passing through the crest of the covering mass, with a drop of from 12 to 15 degs. for revetments, and 15 to 20 degs. for detached walls,^ and making a horizontal angle with the wall, of not less than 45 to 60 degs. according to the nature of the material; provided always that the effects of the firing can he observed. Under these circumstances, walls, the cordons of which are covered from a drop of 1 in 4, will still be safe against curved breaching fire, unless very low, until the levelling of the covering mass. Gene- rally the widening of the ditch for the caponier is a favourable place for breaching, particularly as the debris may help to smother the caponier. As a rule, at least two breaches should be made, each as wide as possible, say 30 to 60 ft.^ The forma- tion of a breach should be postponed to the last, in order to prevent the defenders from retrenching or barricading it — as happened at Soissons in 1870, where the French bravely worked on the breach under a ^ In the new forts at Strassburg, a line of fire perpendicular to the detached walls would need a drop of 17 degs. to reach even the top of the wall. The Austrians, after the breaching of a detached wall at Borgo- Forte, decided to cover walls fiom a drop of 1 in 4. ^ In firing down narrow ditches, a slight increase In width of breach may be got, by letting the guns in batteiy cross their fire, as was done at Strassbui-g in 1870. close attack. IN THE FUTURE. 87 night fire of shrapnel — or even to stop the defenders from doing intentionally, what the assailant did by accident at Strassburg in 1870, namely, raising the covering mass artificially across the line of fire, pro- vided a night be allowed them ; in which case, also, progress might be delayed by laying rails, logs, &c., on the earth above the breach, to burst shells fired with the object of bringing it down. Supposing, however, that breaches have been made. Necessity for an assault cannot be risked, without learning that they ~' "'" ' are practicable, or that they have not ceased to be so, by the removal of the debris from the foot of the wall : this, if any respite were given, might be effected by laying a rail tramway along the counterscarp, from the breach to a convenient distance. Nor would it be practicable, even with the certainty of finding a breach, to advance any distance over the open, as long as the works are defended : hence it is evident, that breaching at long ranges, by no means lessens the ne- cessity for advancing the siege works to the counter- scarp ; as soon, therefore, as the defenders' fire permits, further approaches are carried forward, and parallels made. During the war of 1870-71, the difficulties of the close attack, under modern conditions, were only in part experienced ; because the power of resistance, even to a distant artillery fire, was so small that, ex- cept at Paris, there was no reserve of force left, to oppose the close attack. In the future, however, we may expect, that the defence will mend matters in this way, and that the contest with the second artil- lery position will be a severe one, before the attack gains the mastery; particularly if the defence suc- ceed in maintaining their rifle fire from the parapets. Still, the great increase of the effective range of musketry enables the defenders of each parallel to command a wide extent of ground to their front; hence the necessity for having five parallels and se- veral demi-parallels, as described by some writers, is not anticipated, and it is thought that a second and third parallel, or portions of them, each at a rather greater distance from the fortress than from the pre- ceding one, with short lengths of lodgments from tlie 88 THE ATTACK OF FORTRESSES a]iproaches, will bring us close to the glacis ; beyond this, if mining be necessary, a mine lodgment must be made, and an advance made by mining; while, in the absence of mines, the advance will be by sapping till the counterscarp be reached, where a final lodg- ment or crowning will be formed. Defilade of the In dealing with a small fortress or isolated work, approaches. -^ ^^^^^ -^^ possiblc to dircct the approaches in front of the parallels so as to be secure from enfilade ; but with a girdle of forts on a large circle, even if they do not mutually flank the near foregrounds, the coun- ter-approaches between them will do so, as in the case of the southern forts of Paris (pi. viii.) ; hence, in many cases, an advance by zigzags^ will be im- possible after a time, and this will, more than ever, drive the assailant to proceed by direct lines. As long as the exposure is not great, the advance is by common trenches ; the sections of the tasks being the same as for the first parallel. As we near the for- tress, the power the defender may have of illuminating the ground by electricity and light balls, added to the difficulty of keeping down his fire at night, may now, in some cases, make it easier to work by day than night. In this way, at Strassburg in 1870, the French fire was so kept down in the day-time, that flying sap was used throughout in the advanced attack. Before Charleston, in 1863, saps were car- ried on in the day-time under musketry fire, and sometimes against the fire of the artillery, though the latter generally stopped them.^ In any case, to Thewq.s. get cover early, common or flying sap must be used ; and the latter, on account of its greater quickness, will be employed, whenever possible, in the further advance. The difiiculty is the weight of the common gabion, two of which cannot be carried far. Accordingly, the Austrians^ propose a carrying party, who each brings up one gabion and go forward as a covering ^ By a slight mistake in tracing an approach at Strassbuig in 1870, it was laid open to the French, and several men and officers in it were killed. 2 Gillmore, p. 213. ^ Briuiner. IN THE FUTURE. 89 party, while each of the working party brings up a second gabion. The result is a constant confusion, as the parties get mixed. The Prussian plan is similar, but better arranged, as the carrying men are first retired before the workmen come up; but thus a double strength of men is turned out, and exposed at the most unfavourable moment. We believe our plan to be the best, if pains be taken to make the gabions so light, that two can be carried up by one man in addition to his tools. Very stiff gabions can be made of wire netting. Light gabions, combined with ordinary wicker work (figs. 37 and 38, pi. xxi.). Those 2 ft. 6 in. wide, weighing only 18 lbs. each, allow the men to adhere to the usual task, two paces long; though they can, of course, be made circular, like a common gabion, with even less weight.^ The gabions would be brought up to the most advanced trench depots, whence the parties would carry them to the tracing. The Avorking parties would advance over the steps in the parallels, in Avorking columns, and be extended by files, as already described ; or, when they are small, and the Avork near the lodgment they start from, they can file out in single rank after the directing officer. In cases of great exposure, flying sap Avill be done by giAdng each man one of the service sap-shields,^ or any avail- Sap-siiieids. able iron. These shields Avill also be very useful for general purposes, such as covering very exposed sentries. The Germans, at Mezieres in 1870, used ' It is here worth remarking, that the wire netting for 1,000 gahions weighs about 1^ tons, as compared with 10 tons, the weight of tlie gabion bands for 1,000 band gabions; even, therefore, when the latter could not be brought up, the former might easily be carried. In the absence of wire netting, a light gabion may be made by substituting three sand-bags, or strips of carpet, canvas, or dry hay-bands. ^ These are of steel, 3 ft. 6 in. x 1 ft. 9 in. x -^^ in., and weigh 54 lbs. As they are capable of resisting the 480-grain M. H. bullet, the penetration of which is, at least, as 1 1 to 8 compared with most small arras : it is a question whether a thinner and wider shield might not answer better. The Austrian steel shield is 3 ft. x 2 ft. x 0-2 in. Steel ^'q in., or iron ?- in. thick, on 3 inches of hard wood backing, is bullet-proof. 90 THE ATTACK OF FORTRESSES plate-iron from a factory to make 500 feet of covered communication ; and the French, at the second siege of Paris (1871), used plates of ii'on on timber, as shields across roads of approach. By these methods the approaches may be carried forward to the second, and sometimes to the third parallel, by flying, or ordinary single sap. When, however, zigzags become impossible, the approaches may advance somewhat as in figs. 42 or 43, either by double flying, or double ordinary sap ; the great advantage of the former being its rapid progress, and also that, with it, gabions are used ; for, with the common deep saps, the difficulty of placing gabions, has now led to their disuse. Formerly, 3 ft. was considered deep enough for saps, but, owing to the greater use of curved and high-angle fire, and the formidable effects of shrapnel, a depth of 4 ft. is required in the flying sap, and of at least 4 ft. 6 in. in the common saps (figs. 41 and 36).^ The advan- tage of this method is that the T heads act as tra- verses to the branches, and are therefore raised as high as possible ; thus, a height of 5 ft. would give fair cover against a drop of 1 in 6 for a length of 30 feet of branch. When, however, it is desirable to make the branches longer, they must be blinded (figs. 42 and 51), and deepened from each traverse to the rear ; one or two such blindages would allow the branch to be increased 30 to 60 ft. It has been suggested that these straight approaches are defenceless against flank attacks; as, however, they will always be flanked by musketry from a parallel not over 300 yards from them, it does not seem necessary to make them wide enough to have steps; while in the case of night attacks, the guard of the trenches could stand, under shelter of the tra- ^ The Prussian sap is 4 ft. 6 in., and the Austrian deep sap 6 ft. deep. The former is said to advance at from 4 to 5 feet an hour ; the latter, according to Brunner, from 4 to 6 feet I Our experience with a sap of 4 ft. 6 in. is, that a progress of 4 feet an hour is un- usually good. With the old 3-ft. saps 7 or 8 feet was a good rate, and when opposed to inferior arms, we should still use them to save time. IN THE FUTURE. 91 verses, on the central tongues, during the progress of the sap (fig. 51), and flank the advance of a sortie. For regular sapping, the gabion, as well as the Saproiiers. sap-roller, has been abandoned on the Continent. With increased depth in the sap, the difficulty of placing the first justifies its disuse; but the replacing of the sap-roller by an earthen parapet, constantly turned over, greatly delays progress; while the ob- jection to the brushwood sap-roller, namely, its ex- cessive weight of about three-quarters of a ton, and consequent clumsiness, may, it is thought, be got over. One substitute on favourable ground will be a pair of steel sliields on some form of sloping frame on wheels. These, however, are apt to be displaced even by a heavy splinter, and in many cases we would prefer a sap-roller stuffed with cotton, and Cottonstuffin^ light enough to be lifted as well as rolled.^ On rough ground, where nothing will roll, the earth cover to the sap-head might be replaced by a movable heap of sand-bags filled with cotton, each weighing only 8 or 10 lbs., and therefore easily tlii'own forward. Agam, in cases of extreme ex^DOsure, portions of flying sap, and lodgments for riflemen may be formed by rolling up a line of sap-rollers, light enough to be manageable, and behind which men could work under musketry fire. Gabions filled with cotton would also ^ Cotton, even when not to be got from bedding, (fee, can always be brought up, and when compressed is not bulky — a bale of 5 or 6 cwt. being only 5' x 3' x 1'. Loose cotton, stuiFed by hand, weighs only 4 to 8 lbs. to a cubic foot ; while, from the experiments mentioned by Gill- more (p. 253) on cotton in bags, the penetration of the rifled bullet into it appears to be only 22 inches, or twice that into sand : so that, weight for weight, it has about 9 times the resistance of the latter. The weights of 6-ft. sap-rollers, with wooden cylinders and cotton stuflSng, would, for diameters of 2, 3, and 4 feet, be respectively about 220, 360, and 470 lbs. : so that, at need, they could easily be carried over para- pets and rough places by two to four men, and they might be stuffed in the advanced trenches. Untwisted hawser strands, such as are used for mantlets, are also suitable : their weight is about 20 lbs. to a cubic foot, and a thickness of 6 in. is bullet-proof. A thickness of 3 in., stuffed between an outer and inner cylinder of brushwood, would make au eflRcient sap-roller of about the same weight as those stuffed with cotton. Both hemp and cotton can be made uninflammable, by a so- lution of chloride of calcium. i 92 THE ATTACK OF FORTRESSES give immediate cover, and they and the rollers could be used elsewhere, when the parapet was thrown up. Steel shields, too, when available, will be put to a similar use. The ordinary double sap with traverses is com- plicated, and being in one line is apt to be enfiladed for its whole length ; while, for the methods shown in figs. 42 and 43, the branches might be done by single saps back to back, and the T end by flying sap, with sap-rollers, shields, or gabions; generally at night, and, if possible, beforehand, so as to screen the direction of the sap from the front : for which purpose, also, screens meant only to conceal may sometimes be used. As the saps will suffer most from curved defen- sive fire from the outlying counter-batteries, they should, in general, be directed on the capital of the fort, so as to benefit by its shelter. WAR OF MINES. We have now to consider how the defenders' countermines must be dealt with. Mining is one of the earliest arts used in war, and new changes have only increased its importance; for instance, by arming it with powder, and more recently because it is a defensive resource which has not been impaired by the improvement in arms.^ The slowness of its progress is the chief objection to mining. As far as expenditure of life is concerned, it is most economical. At Schweidnitz, where the assailant spent 47 days in ^ A Memnonian bas-relief of 2000 B.C. shows the Egyptians, pro- tected by mantlets, undermining a fortress wall ; and Josephus (lib. vi., chap, vii.) mentions that Saul attacked the cities of the Amalekites with mines — " opvy jiacnv virovojuioig" Polybius relates that the Persians took Chalcedon, by mining under it for a distance of 15 stadia; and Thucydides (lib. ii.) speaks of countermines at the siege of Platsea; while Cfesar complains (lib. vii.) that, at the siege of Avaricum, the Gauls, with their mines, would not let him build his agger " et aggerem cuniculis subtrahebant." Powder was first used in mining, by the Ge- noese, at the attack of Serezzanella in 1487. IN THE FUTUr.E. 93 milling, he only lost 25 men; while the French loss in mining at Sebastopol was only 45 men killed and wonnded. The defence has in its favour a prepared and or- ganized system, with better means for earth-boring, for ventilation, and for drainage, &c.; but as it can- not afford to furnish the assailant with lodgments on the surface, it can only hre small charges, with a radius of destruction of about 20 feet, the partial effects extending about one-half further. It can also use small charges (fig. 47) so lodged as not to injure its own galleries, but to poison the earth and injure the assailant. The assailant, on the contrary, may use the largest charges. These enable him to destroy the defensive galleries, at a distance beyond the reach of the defenders' limit of destruction, and also to get the cover of large craters. If the ground be The mine mined, a mine-lodgment like a demi-parallel is formed •o'lgments. a little short of the supposed zone or mine-field. Here a blinded depot of mining tools, and a maga- zine are formed, and supplies collected. The methods of the attack are based on such Methodaof knowledge of the countermines as can be obtained. ^^^^'^^' They are : — 1st. To drive galleries from the lodgment till within 25 to 35 feet of the countermines, and then fire over- charged mines of 7,000 to 8,000 lbs., which destroy the defenders' galleries to a distance of 50 or 60 feet, and form craters of 65 to 95 feet.^ These craters should not, if possible, bloAv in the mine lodgment, but should overlap each other. In any case they are at once occupied, and crowned by a rude flying sap, and connected with the rear. From these lodgments, galleries are advanced, and fresh ground gained. 2nd. Instead of driving galleries, when speed is required, or the earth is poisoned, to use large earth augers, boring to a depth of 20 feet or so from the mine-lodgment, or craters ; as the hole they make is only 9 to 12 in. in diameter, charges of cotton are fired in them instead of powder. The surface effect Gun-cotton. ^ A charge of old powder of 7,700 lbs. fired at Graudenz in 1873, with a L. L. R. of 25-3 ft. made a crater of 94 ft. in diameter. 94 THE ATTACK OF FORTRESSES of gun-cotton in earth is small, but experiments have shown that its lateral effect is at least 2| times that of powder. We are, therefore, bound to use it, whenever we shall not be hindered by its after effects on our own operations, and when the de- struction of the defenders' galleries is more impor- tant than the formation of large craters. 3rd. To make a hasty lodgment above the de- fenders' galleries, whence shafts are sunk at 1 or 2 lined intervals, and at the bottoms of these, to fire heavy charges of cotton or powder, so as to crush the galleries below,^ and cause the loss of the ad- vanced parts. This method is evidently attended with much risk of failure, but shortens the opera- tion, and in the long run saves lives. The French, in the operations before the Bastion du Mat, at Sebas- topol, fired charges at the bottom of shafts in this way, but without much effect. 4th. To drive a shallow gallery in the place of the lodgment, and fu'e charges along it to destroy galle- ries below, and provide a safe lodgment. This was done with partial success by the French before the Bastion du Mat, where they fired 23,940 kilos, of powder in 17 charges, about 10 metres apart. A trench was thus opened, except where some charges failed, but a stratum of rock saved the Russian mines beneath. With this object it has been suggested that charges of gun-cotton should be laid bare on the ground, so as, when fired, to make a surface lodgment.^ There are a few of the details of mining we would wish to touch on, these are : — Ventilation of ^^^- '^^^ ucccssity of providiug proper means of mines. veutilatiou. In the galleries of the attack, with a rapid fall inwards, the carbonic acid from respiration collects at the head, and a method of exhaustion is therefore necessary. Again, in working in poisoned earth the great danger is from carbonic oxide, 1 or 2 per cent, of 1 Niel. '^ A charge of 500 lbs. of gun-cotton, fired on the surface of the ground, has been noticed to make a crater of a diameter of 22 feet and 3 ft. 6 in. deep. IN THE FUTURE. 95 which is fatal, though it does not interfere with the burning of lights. Here, then, this light gas must be expelled by the influx, under pressure^ of fresh air from beyond the entrance. Turbines fail in providing enough pressure, and bellows in giving enough quantity, because, for the attack, hand-})ower Air engines. alone is available. There are, however, several forms of pressure-blower in use in this country which pro- mise to suit our purpose, as they either exhaust air, or, when reversed, impel it with pressure (figs. 54 and 55, pi. xxii.) .^ Further, the plan of a face mask (figs. 50, 52, and Respirators. 57), which enables a man to breathe pure air through a stiff 1-inch flexible pipe as far as 70 to 80 feet from the entrance, is excellent ; and a number of these, with their pipes, &c., would be all that is wanted of this kind for the short attack galleries ; though a few com- pressed air knapsacks (fig. 26, pi. xx.), and a pump are desirable additions to the siege mining equip- ment, in case of having to deal with complicated or captured galleries,^ the more so as the pump can be used to supply air to the wearer of a face mask when the distance is too great for the use of the pipe alone. 2nd. The necessity of combining Ord's hose, and a short length of Bickford's fuse, with all electrical arrangements for firing. 3rd. The provision of bomb-proof porches over all entrances to galleries. 4th. The use of sun-dried bricks, and logs of wood in default of sand-bags for tamping. We can seldom reckon on sand-bags for this purpose, though with them, the small galleries can be tamped at the rate of nearly a foot a minute. 5th. The desirableness of testing the new pebble powders, to see how far the surface eff'ects are in- ^ The lightest, of 84 lbs., can be worked by one man, and gives a blast of 60 c. f. a minute ; those of 4 cwt., worked by four men, give 150 c. f. Stiff india-rubber hose must be used, and the pressure can be varied by having nozzles of different sizes. "^ Of these knapsacks, twelve are provided in our " Siege Equip- ment ;" but apparently no pump. 96 THE ATTACK OF FORTRESSES creased by using them, and whether the lateral effects are altered. .Alining cases. 6th. While bclieving that the dimensions of our mining galleries are, without exception, the best, we think the pattern of case might be improved. The necessity of leaving a space over a corner is incon- venient, if not unsafe, and those who have mined with their own hands, know the loss of time that occurs in just fitting in the last corner of an obstinate case. If we did away with top tenons (fig. 44), and let No. 1 jam the sides roughly into place, at the top, by a screw compressor; the other Nos. could make alterations, if required, at a convenient distance in rear of No. 1, and add top battens, with a crushing resistance as great as the cross breaking resistance of the side pieces (fig. 48). This would save the time of No. 1, on wdiom the rate of progress depends, and would sup- port the earth so effectually that, with cases at inter- vals, the intermediate earth roof w^ould arch itself, like the brick arches between girders : so that with fewer cases we should have greater safety than at present. The compressors might also be used, on an emer- gency, to strengthen the heads of galleries when an explosion is feared. We cannot leave the subject of mining, without noticing the attempts that have been made to obtain by means of steam used directly, or through the medium of compressed air, a greater rate of progress than the miner can maintain. So far, these have not succeeded : had they done so, bearing in mind the difiiculty of using steam in so exposed a position as the mine lodgment, the balance of advantage would, it is thought, have rested with the defence. For the attack, the use of a mining machine which appears most feasible, is to apply it to work an auger, at a rapid rate, and fit to make a hole of sufficient size to take a fair charge of gun-cotton, the chamber being, if necessary, enlarged by firing a few very small charges in it beforehand. By constantly driving these in front of their work, the attack could ward off the defenders' strokes, and progress both more quickly, and with less loss. INIining macliines IN THE FUTURE. 97 Space docs not permit us to enter into the details of the further advance of the saps to tlie counter- scarp ; but they can now l)c arranged with greater simplicity, owing to their behig uncomplicated in most cases by artillery arrangements, and, combined with this, they will have less width, greater depth, and more overhead cover. When the counterscarp wall is reached, it may be ncmoiitioiiof necessary to blow it in with over-charged mines, •^'^"'"'^'•'*<'"P- either to render the artillery problem more easy, or to fill uj) the ditch, as was done at Schweidnitz, where the explosion formed a practicable ramp against the escarp; or, again, to smother or mask the low flank- ing defences of the ditch. In cases where curved fire or the use of gun-cotton bombs has failed to silence these latter, or to breach the detached wall or escarp, mines may, with these objects, be carried under the ditch. In general the counterscarp wall will be cut through by hand or by using gun-cotton, and covered passages will be made across the ditch. As it is now no longer necessary, as a rule, to '^maii gauges provide means for bringing guns into the ditch by °^'^''^'^''"*- great or blinded galleries, and as these have always presented great difficulties; it is believed, that the counterscarp can now be reached most surely, by a number of common galleries three feet wide, if neces- sary, which can be driven close together, at known rates, and in much less time than it takes to drive the great or blinded galleries ; ^ though in a case like that at Lunette 53 at Strassburg, where there is no counter- scarp wall, and where a comparatively shallow open cutting can be made and roofed, the blinded gallery is less objectionable, and a roof of rails, as used there, is desirable. When these galleries reach the wall, returns should be made behind it ; the galleries should be tamped and shored till the wall is blown in ; and when the breach is formed, and the caponiers silenced, they should be opened, and used to give a large front, either to assaulting columns, or to working parties employed to pass down earth or fascines for filling up 1 P. P. K. E.. vol. xix., p. 3(J. II 98 THE ATTACK OF FORTRESSES Eiivtli mortars. still water ditches, or small piers of metal-lined cases, powder barrels, &c., for bridging running water, and filled sand-bags or cotton-bags for parapets. In this case, as 2 or 3 feet is hardly wide enough, the miners that follow No. 1 could form recesses for a chain of men on each side, who could stand in them and pass down what is required ; the formation of these need not delay the progress of the galleries (fig. 49). The preparation for the assault will, of course, be made by the greatest possible amount of fire on the breaches, and the interior of the works, where the defenders will have prepared covered blindages for the reserves who are to resist assault ; but, in addition, a belief seems to be afloat, that both then and earlier, means must be found for throwino- in larg-e masses of the new explosives, which by the shock of their detonation, will clear away everything in their neigh- bourhood. We have heard lately of savartines or shell-fou- gasses, but the statement that they carry dynamite must be accepted with suspicion. Wet gun-cotton, however, is a perfectly fit material, and it is only a question as to how the largest charges can be just carried into the work. Very large mortars, cause their shells to bury themselves too deep if fired from a distance, though they may yet be forthcoming in a form available for close quarters. In their absence, the means to use are either a powder rocket acting as a vehicle, or an earth mortar formed by revetting the sides of a hole in the ground. If the first can be got to work, it is believed it would, on the whole, answer best. If not, deep holes in the ground, lined with wrought-iron tubes in quadrants (figs. 53 and 56), will act as mortars, and might throw wrought-iron shells, made in segments for transport, and strength- ened inside with flanges, so as to carry 600 or 700 lbs. of gun-cotton ' (figs. 45 and 46). The ex- ' Wooden cylinders over 700 lbs. in weight liave been fired on the Continent, from holes lined with battens, with charges of about ^'^^th the weight of the shell, they ranged for diatanees over 350 yards. attack. IN THE FUTUliE. 9i) plosion of one of these a^^ainst a detached wall (fl<,^ ^9) would rarely fail to breach it, while a few of them would wreck the interiors of most works. CONCLUSIONS. In the foregoing remarks the attempt has been made, not so much to give a detailed description of the suc- cessive steps in a siege, as to dwell on those features which in these days have, perforce, been subject to the widest clianges ; and, further, by the light of re- cent ex})erience, to point out what appears to be the drift of the changes we may expect in the near future. The general result, as regards the attack of for- tresses, may, it is thought, be summed up as follows, namely, that the different stages will be : — sta-tsofti.e First Stage. An investment; conceived secretly, completed promptly, maintained rigidly. For the first is wanted unity of command ; for the second, good information and mobility in all arms; for the third, aptness in applying all the arts of field fortification, and in developing to the utmost the re- taining power of the new arms ; in using the power of rapid concentration that is given by the field tele- graph; and in employing the means of transport and supply afforded by steam. Second Stage. The selection of the front or fronts of attack. The approval of a siege plan. The preparation of the siege parks, and particularly of the communications to and from them by railroads or roads. The bringing up of the siege trains. The collection of the local siege materials, and the use of steam for the preparation of the timber work. The pushing forward and strengthening of the line of investment; as well as the commencement of the and had an initial velocity of over 17U feet. Both the shells and their time fuses were fired hy electricity. They only went about twelve inches into the jjround on fallini'. 100 THE ATTACK OF FORTRESSES earliest siege works out of sight of the defenders, and, as far as possible, without their knowledge. Third Stage. The completion of the first artillery position, at a distance from the fortress, which, roughly speaking, will be more than three times as great as in the days of smooth bores. The arming of the batteries. The opening and maintenance of the first bom- bardment, protected by a covering force. The fights for the intermediate localities, under cover of the bombardment. The gradual confinement of the defenders within the zone of the musketry fire of the place. Fourth Stage. The establishment of the attack in an infantry position extending along the borders of the musketry zone of the defences, enveloping, as far as possible, the fronts attacked and the area of the further advance, and composed of existing and arti- ficial cover, as well as provided with covered com- munications to the depots in rear. Further, the construction of a second artillery position in the neighbourhood of, and protected by the first parallel — Avhence, in great measure, the work of destruction to be carried on by the guns, will be effected. Fifth Stage. The further advance (along the most direct lines) of approaches provided with overhead cover, against the searching power of modern shells. The protection of these approaches, at convenient intervals, by additional parallels and lodgments ; and the complete suppression of the defenders' fire by the constant use of light guns, mortars, wall- pieces and musketry. Sixth Stage. The war of mines, by which a final advance to the counterscarp is made; or, in their absence, the advance thereto by sapping. The crowning of the crest of the glacis. The breaching of the escarps, and silencing of the caponiers by distant artillery fire, aided by observa- tions from the near approaches, and by the miners' advance to, and demolition of the counterscarps and caponiers when necessary. IN THE FUTURE. 101 Seventli Stai^e. The expulsion of tlie garrison from the neighbonrliood of the breaclies, by bringing the fire of all available arms to bear thereon ; and further perhaps by the use of masses of gun-cotton, carried in by rockets or by earth mortars. The passage of the ditches by the ordinary me- thods, and the simultaneous assault in force of all the breaches; followed by the capture of the work or works. Eighth Stage. The armament of the gorges of the captured works, the connection of them by tele- graph, and the use of them as keeps in a new base of attack against any further defences, the advance against which is carried out on the same principles. Such, it is believed, is the state of things we must prepare for. The successful conduct of such enterprises must conditions for depend : — success. 1st. On the numerical fitness of the force em- ployed. 2nd. On the moral and physical qualities of all arms. 3rd. On the technical knowledge of the special troops. 4th. On the state of national preparation, as re- gards arms and materials. For the first, rules must always be qualified by the circumstances of each case, particularly when, as in the war of 1870-71, the widest diflferences may exist between the troops engaged. For the second, we must remember that the soldier hates trouble; and though, in the excitement of a fight, great efforts may be relied on, the monotony of the work, and the severity^ of the labour of a siege will always be distasteful. Hence discipline, combined with the personal influence and exertion of the ofiicers, can alone secure the execution of the works with such promptness as the physical fitness of the men permits. * Towards the end of the siege of Strassburg in 1870-71, so ex- hausted were the men, that the reliefs, in returning- from work, pre- ferred to cross the open, under tire, rather tlian march a few jaids further to gain cover. 102 THE ATTACK OF FORTRESSES IN THE FUTURE. P'or the third, it is necessary that the technical troops should practice in peace all that they will have to do in war, and under conditions approaching those of war as nearly as possible. That the artillery should have put their weapons to the exact uses they will have to put them to at a siege. That the engineers, while learning from their peace employment the best ways of conducting Avorks/ shoulcl, in conjunction with the other arms, and away from the facilities provided at head-quarters, have opportunities of executing every form of field and siege work. Lastly, in these days when war is declared hy post ^ but begun by telegraphy there is often scant time for getting ready; and not only should our ideas be matured, but our men and materials should be ready too. In this peace-loving countr}^, happy in being free from the thirst for conquest, it may be objected that fighting only concerns us in reference to self-defence : even so, the best preparation for defence is the study of the attack ; but a nation that rules nearly a fourth of the inhabitants of the globe — most.of them too on the sole condition of readiness for offensive war — cannot calculate for ever on fi-eedom from the necessity for it, a freedom that all history shows, is never un- limited ; while from the same source we learn, that fitness for oftensive war is the best security for peace, and that the most matured wisdom dictated the saying — " Si vis pacem, para bellum." ' From tlioir experience in the coiuluct of work, the Aniericun en- gineers at the siege of Charleston showed, it is thought, more origiiiahty of design, and more holdness in execution than tlie Germans did in all the sieges of the war of 1870-71. UNS. RIAN. 400 guns each.) Propor- tion in train. 1 in 20 1 in 20 1 in 4 1 in 4 1 in 10 1 in 10 1 in 10 1 in 10 Weight. Gun cwts. 95-91 40-14 63 30 291 12-8 Shell lbs. 192-6 85 65-4 60-8 35-5 17-7 rifled) . . 36-48 cwt. ditto . . 50-75 Ib.s. with different shells 5 ided per gun . . ITALIAN. (One train of 200 guns.) Description and Calibre of pieces. Propor- tion in train. 22 c. M. L. R. Mortar . j 1 in 6-6 16 c. M. L. R.Gun . . l in 3-3 12 c. M. L. R. Bronze ) L . „ Gun !^"^2 15 c. S. B. Mortars. 1 in 20 Weight. Gun cwts. 89-4 60-5 205 65 Mean weight per piece (rifled) . . 38-76 cwt. Mean weight of shell ditto . . 62-5 lbs. Number of rifled pieces with different shells 3 Number of rounds pi-ovided per gun . 500 to 975 REMARKS. ' The details of the foreign trains are ex- tracted from the " Jahres- berichte" of 1874. « The 64-pr. M. L. R. Gun will also have a 90 lbs. battering shell. ' To be replaced by 21C.B.L.R. Howitzers. Some of the 15 c. Guns are to be ring-guns. * These mean weights are the total weights of metal, divided by the total numbers in the train. pach of the two units. 102 THE ATTACK OF FORTRESSES IN THE FUTURE, For the third, it is necessary that the technical troops should practice in peace all that they will have to do in war, and under conditions approaching those of war as nearly as possible. That the artillery should have put their weapons to the exact uses they will have to put them to at a siege. That the engineers, while learning from their peace employment the best ways of conducting works, ^ should, in conjunction with the other arms, and away from the facilities provided at head-quarters, have opportunities of executing every form of field and siege work. Lastly, in these days when war is declared hy post ^ but begun by telegraphy there is often scant time for getting ready; and not only should our ideas be matured, but our men and materials should be ready too. In this peace-loving country, happy in being free from the thirst for conquest, it may be objected that fighting only concerns us in reference to self-defence : even so, the best preparation for defence is the study of the attack ; but a nation that rules nearly a fourth of the inhabitants of the globe — most^f them too on the sole condition of readiness for oftensive war — cannot calculate for ever on fi-eedom from the necessity for it, a freedom that all history shows, is never un- limited ; while from the same source we learn, that fitness for oftensive war is the best security for peace, and that the most matured wisdom dictated the saying — " Si vis pacem, para bellum." ' From their experience in the coiuhict of work, the Amciican en- gineers at the siege of Charleston showed, it is thought, more originaHt y of design, and more boldness in execution than the Germans did in all the sieges of the war of 1870-71. APPENDIX A. TABLE OF REVISED EUROPEAN SIEGE TRAINS.' BRITISH. (Equal proportions of light and heavy units.)* PRUSSIAN. (Two trains of 400 guns each.) RUSSIAN. (Two trains of 400 guns e.tth.) AUSTRIAN. (Two trains of 400 guns each.) ITALIAN. (One train of 200 guns.) REMARKS. Propor- 'tr°.°in° Weight. of pieces. Propor- tion in Weight. Description and Calibre of pieces. Pi-opor. weight. of pieces. Proper- Weight. De.cc,p„„n.ndCa,.b.e ^J^ Weight. Description and CaUbre of pieces. e"::. t,!' Qnn lbs. cwts. ' lbs. ■bf Qtm SheU lbs. 8in.(20-32f,)M. L. E. ) Howr i 6-3 in. (16 c.) 64-pr. do. ) Gun J 6-3 in. (16 c.) 64.pr. ) I in 4-3 46 64 18 18 181-5 64 40 25 21c.B,L.E.Mortar3. I5c.LongB.L.R.Gun 15 c. Short do. Gun . 12 c. B. L. E. Gun . . 9C.B.L. R.Gun . . 15 c. S. B. Mortars . 0-9 in. Wall Pieces . . linlO linlO 1 in 3-3 1 in 3-3 linlO 1 in 2-6 60 59 05 29-5 17-1 8-4 0-55 176 61-1 : 14-2 20 c. B. L. R. Mortar . 15 c. LongB.L. R.Gun 15 c. Short do. Gun lie. B.L. R.Gun. . S. B. Mortars . . . Do. do 1 in 6-6 1 in 2-9 linS 1 in 10 linlO 77.2 30-8 (4375 32-2 15!) 175-6 64-4 64-4 28-3 116 29 21c, B. L. R, Mortar. 17 c. do. do. . 15c.LongB.L. E.Gun 15 c. Short B.L.R. do. 12 c. B. L. R. Gun . . 9 c. do. do. . 30 c. S. B, Mortar . . 15 c. do 1 in 20 lin20 lin4 I in 4 1 in 10 1 in 10 93-91 40-14 63 30 291 12-8 192-6 85 60-8 35-5 17-7 22 c. M. L. R. Mortar . 16 c. M.L.E.Gun. . 12 c. M. L. R, Bronze } Gim ) 15 c. S. B. Mortai-s. . 1 in 6-6 1 in 3-3 lin2 I in 20 89-4 60-5 14-4 205 .. 24-5 ' The details of the foreign trains arc ex- tracted from the "Jahres- berichte"ofl874. ' The 64-pr. M. L. R Gun wiU also have a 90 lbs. battering sheU. = To be replaced by 21c.B.L.R.Howitiere. Some of the 15 c. Guns are to be ring-guns. Mean weight ' per piece (rifled) . . 3576 cwt. Mean weight of shell ditto . . 77-7 lbs. Number of riHed pieces with different shells 5 Number of rounds provided per gun . . 600 Mean weight per piece (rifled) . . . 297 cwt. Mean weight of shell ditto . . 58-3 lbs. Number of rifled pieces with dilTerent shells 4 Number of rounds provided per gun . . 500 Mean weight per piece (rifled) . . . 34-3 cwt. Mean weight of shell ditto . . 49 lbs. Number of rifled pieces with different shells 3 Number of rounds provided per gnn . . Mean weight per piece (rifled) . . 36-48 cwt. Mean weight of shell ditto . . 50-75 lbs. Number of rifled pieces with different shells 5 Number of rounds provided per gtin . . Mean weight per piece (rifled) . . 3876 cwt Mean weight of sheU ditto . . 62-5 lbs. Number of rifled pieces with difierent shells 3 Number of rounds provided per gun . 500 to 975 « These mean wT>ights are the total weights of metal, divided by the total numbers in the train. ; 7-pr. M. L. R. guns of ^00 I! , to be used on beds as n 1 ^ th^ cefttt'ol dr-uftv J^'ewisry (£ 7'^tU.r. i.iA. SJ, PlaAe.XIX. ^pp?¥'^^Jf!^'^fW^9^y^Wf-f', 18 mJ J'f'-i^ej- and cha/n- to L&ty dft(xciunen.t' U/h a.- 6 cwt Gtui . 4.0 ff'er^'S. Fi,a. 22. AsUcbnff car-nage- tnul si i tie i.i shcfwn chain dotted- . The sUdt/ rests en brvad iron flufiged- platen on ttu. ground . Widi, a. slide- the gun. pcnH/jm/ itf dt/fjentd on each side cf ^^evthery Si f'f^.i, utA_ S:, Plate XX. rrLU2,^Ze^ of ^un^. h'mlay i WJa^: iy2u:lirS'&licra, V^),«^ i WiU^ htk. 5 UstUS^BUa Nal^iWli^,hA,iC.^d^smii.r,, YD 00584 UNIVERSITY OF CAUFORNIA LIBRARY