Page:Encyclopædia Britannica, Ninth Edition, v. 9.djvu/498

 466 FORTIFICATION assume a character of the highest importance, but it should not be forgotten that masonry can never resist the effects of a concentrated fire of heavy guns, and can be considered safe only when protected by earthen masks or couvre-faces. The Maximilian towers of the defences of Lintz are no longer approved by modern engineers, and in closing the harbour of Sebastopol against approach by sinking a large portion of their own fleet, the llussians exhibited their dis trust of masonry defences when opposed to ships. And this distrust is not to be wondered at, when it is remembered that, to bring the guns forward enough to afford them lateral training, the walls of casemated batteries must be cut into, and greatly weakened. This great defect of masonry defences, and the evils of smoke in close case mates, are well known to engineers. In the earliest periods of Italian fortification, the necessity of increasing the active power of the flanks beyond that afforded by their length was strongly felt ; and retired flanks, rising one above the other, were adopted, as well as casemated flanks admitting two or more tiers of guns, thus obtaining, as in Montalembert s System, a greater number of guns by extending the battery vertically. At first sight this appears an obvious mode of acquiring a superiority over the attack, in which the batteries can only be extended laterally, but iu practice the retired flanks were soon found to be un tenable, while the front flanks were complete shell-traps, and the casemates were practically useless from the diffi culty of clearing the smoke from them. The systems of Montalenibert partake of the same defects ; and however imposing the appearance of several successive tiers of guns may be, it should be remembered that, covered by a mask, they can only be partially used when the enemy is at a considerable distance, and that exposed to view they can be easily destroyed at 2500 yards by the guns of attack of the calibres now in use. Several writers have proposed systems based upon principles similar to those of Montalenibert, but it is perhaps sufficient here to mention the work of Don Jose Herrera Garcia (Teoria Analytica de la Fortificacion Permanente), as it is unques tionably the most remarkable development of the tower system of defence. Garcia proposes several successive lines of massive casemated buildings or towers, of an egg-shape, connected together with casemated curtains. The towers are surmounted by parapets, which at the ends next the enemy are broken into a series of smaller curves, and are retired or independent of the exterior wall or scarp. As each of these towers is defensible of itself, the work of forcing a way through three lines of them would be most formidable, but the expense of such a system would be enormous. The system of the Swedish general Virgin belongs to the bastioned systems, but it is mentioned here in contrast to Garcia s, as it disperses in the defences separate bastioned forts, of a form somewhat approaching to Eimpler s, and covered by outworks so arranged as to secure the inner works from injury until the enemy has effected his lodg ment upon them. These forts are surrounded on all sides by ditches, and connected together by secure com munications. Ingenious as Virgin s system is, it is manifest that though the loss of one fort would not ensure the fall of the others, it would at least render all the interior space inclosed by the line of forts untenable, and place the town, the arsenal, or other public buildings, at the mercy of the besiegers. This may be said of all detached forts, and it must be again laid down as a maxim that the ultimate value of such forts, as a means of securing an important object, depends on an inner line of defence of a nature to resist any sudden attack or coup-de-main. Detached forts may be, for the purpose of keeping an enemy at a distance, more effectual than a simple continuous line, but they cease to be of use if an enemy can pass them and attack a defective interior line behind, incapable of resisting a coup-de-main. It has been well stated by the French translator of Zas- trow, that the reduction of a place may be considered as a certain amount of work to be performed, the magnitude of which depends on various elements, amongst which the dis position and nature of the works constitute the most im portant ; and that the attack has to perform this work in a certain time, and with certains means, amongst which the principal elements are the quantity of heavy artillery, and the nature of the ground over which the approaches must be carried. When, therefore, it is said that a work forti fied on Vauban s first system would fall on the twenty- eighth day, on Cormontaigne s, with a cavalier entrench ment in the bastion, on the thirty-first, it must be remembered that this implies the possibility of complete investment, and of steadily advancing the approaches over soil easily worked by the sapper ; but that if the invest ment be incomplete, if the ground be rocky, and every inch have to be gained by hard and incessant toil, pro tracting the time during which the sapper is uncovered, and therefore greatly adding to the daily losses in the trenches, such periods may readily be extended to twice or three times their ordinary length. INTRENCHED CAMPS. It would not be proper to leave the subject without a brief description of intrenched camps, especially as they have an important bearing upon the defence of capitals, with &quot;which this article closes. An intrenched camp is a position, prepared beforehand, in which an inferior army rests in security from the attack of a superior army, and from which it may operate upon the communications of such superior army, or in which a beaten army takes refuge for the purpose of reorganization. The position selected for an intrenched camp is usually around the capital, or around an important city, or on an important line of communication. The position should, therefore, contain sufficient space to receive the army for which it is constructed, to contain ample supplies of all kinds, and to keep an enemy beyond bombarding distance not only from the city but from the camping grounds within it. An intrenched camp should consist of a chain of independent forts, with, wherever practicable, a strong inner work ; the forts should be as large as possible, and disposed in a right or slightly convex line. No fort should have undue prominence over the others, as such a fort would be a source of weakness, inasmuch as it might bo at tacked by itself, and being further removed from the centre of defensive operations would be more difficult to succour. The camp should be traversed by free and easy communi cations ; and if it have an interior work, that work should command the whole of the interior. It should also possess facilities for passing rapidly from the defensive to the offen sive, and sufficient interior space for the execution of such manoeuvres as are necessary for the defence of the position. FORTIFICATION OF CAPITALS. Whether capitals, as capitals, should be fortified has given rise to much difference of opinion ; but all autho rities are agreed that the capitals of highly centralized countries must be fortified. In such countries the prin cipal resources of the state, both public and private, are collected in the capital ; in it is placed the centre of government, and from it administration and organization radiate. Such a capital is truly the heart of the nation ; a deadly blow to it stops the national circulation, and national paralysis may and will probably follow. Take, for