Page:Encyclopædia Britannica, Ninth Edition, v. 9.djvu/484

454 the wording of the specification for manufacture, viz.: "The plates must be soft, fibrous, thoroughly welded, and capable of offering good resistance to cannon shot, without indication of brittleness, and without the separation of the several moulds of which they may be composed." This specification was adopted after many experiments with hammered and rolled plates, in which the former, in conse quence of the absence of fibre, conspicuously failed in com parison with the latter. The best material for armour plates is, however, again prominently under consideration ; so great an increase in penetration was obtained with chilled iron shot that the manufacture of steel projectiles was stopped as far back as 1866. Great advances have since taken place in the pro cesses by which steel is made, and steel projectiles of great penetrating power have recently, been under trial; by the use, too, of prismatic powder disposed in cartridges with a definite amount of air space, by which the combustion is rendered more gradual and more thorough, a far higher velo city is obtained with a materially diminished strain upon the chamber of the gun. This has rendered it possible to enlarge the chambers of the heavy guns and to increase their lengths by several calibres, with a resulting increase in energy of about one-third, so that a plate which would keep out a projectile of 800 Ib weight from a 38-ton gun will now barely keep out a projectile of 400 Ib from an 18-ton gun. It is not impossible, however, that by a combination of iron and steel the resistance of armour may be again brought up to the penetrating power of projectiles. During this consideration many curious and unexpected results have been obtained, but they have not been reduced to such a form at present as to modify what is stated above. Tha whole question is, however, full of interest, and will, it may be anticipated, receive considerable development before long. ARMAMENT OF FORTRESSES. The Systems of Fortification having been briefly described, it is right to say a few words here respecting the means of defending a place after it has been fortified. It is difficult to lay down exact rules as to the proportion of ordnance, ammunition, and stores of all kinds required for the defence of a fortified place, seeing they must necessarily vary according to the particular situation of each fortress, the system on which its works have been constructed, and the species of attack to which it may be exposed. If, for example, one of the sides be covered by a morass, swamp, or other obstruction which it is difficult or perhaps impossible to surmount, it must be obvious that a smaller proportion of artillery will be required than if the fortress were equally accessible on every side ; and, on the other hand, a mari time fortress, accessible at all points, will necessarily require for its defence a larger proportion of ordnance than if it were only assailable on one or a few of these points. Where every front is equally exposed to attack, all must be equally prepared. On this subject, however, certain maxims have been established, of which the following appear to be the most im portant. First, the proportion of ordnance, ammunition, and stores should never exceed the quantity necessary for a brave and resolute defence. Secondly, those fronts which are considered the most exposed to attack should be the most completely armed, whilst a partial armament of the remaining fronts may suffice. Thirdly, to the front to be attacked the following pieces of ordnance should -.be allotted, viz., to each Bastion, 1 for the salient, 5 for each face, 3 for each flauk; to the Ravelin, 5 for each face; to the Lunette, 3 for each face, and a few pieces for the places of arms in the covered-way; so that if one front be Completely armed, the proportion of ordnance will be 17 for the Bastion, 10 for the Ravelin, 6 for the Lunette, and 6 for the places of arms, in all a total of 39 pieces for the front. This proportion is less than has been fixed by many authorities, but the range and accuracy of guns has so increased sin je the introduction of rifled ordnance that it will be necessary to provide a traverse for every gun on the most exposed faces, and this, while it affords security to the artillery, materially diminishes the space available for mounting guns. It may be thought by some that this arrangement provides too much traverse shelter, but a few well-protected and well-served guns are better than double the number in exposed positions. Fourthly, when a place is exposed to attack on two con tiguous fronts, the armament of each should be augmented one-half; when it is threatened with attack on detached fronts, the armament should be doubled. Fifthly, each of the other fronts should merely be provided with such a proportion as to secure it against insult. From this it may be assumed that a hexagon having only one front liable to attack should be completely armed on the two adjoining fronts, and that about seven guns per bastion and seven per outwork will be sufficient for the remaining fronts, and that a total of 178 pieces of ordnance will be sufficient for a hexagon. The next consideration is the proportion which the several kinds of ordnance should bear to one another. Ord nance of the higher calibres is not the only ordnance which ought to be employed; in many cases medium and light guns are more efficacious ; for when only troops or working parties are to be fired at, light guns will answer every pur pose ; their range is nearly equal to that of larger guns, und they are more manageable and may be worked with greater rapidity. Short guns of heavy calibre which throw heavy charges of case and shrapnel are best adapted for the flanks ; and, generally, the largest or heaviest ordnance should only be employed to destroy the besiegers batteries and dismount their guns. The light guns, as they can easily be withdrawn, should be placed in the covered-way, in the places of arms, and in the outworks of every descrip tion. The heavy guns and mortars, which are not so easily moved, should be within the body of the place, and as they require large charges of ammunition, they should be less frequently xisecl, and only upon urgent occasions. A judi cious economy of ammunition is a duty incumbent upon every commandant of a fortified place. The conduct of General Chasse in the defence of the citadel of Antwerp was a model in this respect. From the commencement till the close of the attack, ecarcely a single shot was needlessly expended by the garrison. ATTACK AND DEFENCE OF FORTIFIED PLACES. Having brought thediscussion of Permanent Fortifications to this point we may now consider the attack of fortified places, the general system of which was introduced and perfected by Vauban, so that it has ever since served as a model for the plans of his successors. "La resolution cles sieges," says the Marshal, "estune affaire de cabinet. Elle est une suite naturelle do la superiorite que Ton oroit avoir sur ses ennemis ; mais leur execution etant une des plus serieuses, dt-s plus importantes, et des plus difficiles parties, die dcmande aussi le plus de mesure et de circonspection. He then goes on to state that the success of sieges depends on several cir cumstances, such as "1. Du secret, sans lequel il est diliicile dc reussir; 2. Des forces que Ton a sur pied pour attaqucr les places des ennemis, et defendre les sicnncs ; 3. De la disposition des ennemis ; car s ils sont minis, et aussi forts que nous, ils peuvent nous empecher d en faire ; 4. De IVtat des magazins les plus ;i portee des lieux sur lesquels on pent entreprendre ; 5. De la con- joncturc des terns, pavce que tous nc sont pas propres aux sieges, et rien n etant plus ruineux que ceux d hyver, on les doit eviter tant qu on pent ; 6. DCS fonds necessaires a. leurs depenses ; car 1 argent est le nerf de la guerre, sans lui on ne syauroit reussir en rien. Co