Page:Encyclopædia Britannica, Ninth Edition, v. 9.djvu/456

442 FORTIFICATION tor-general of all the fortified places belonging to the United Provinces of Holland, was the contemporary and rival of Vauban. This able engineer, convinced that, however ex pensively the rampart of a town may be constructed, it cannot long resist the shock of heavy ordnance, invented three different systems by which such obstacles are thrown in the way of a besieging force that, although the place be not thereby rendered impregnable, it can only be reached with great difficulty and hazard. But these systems, with out modification, are only applicable to low and swampy situations, such as are to be found in Holland, and are therefore not available in localities of a different description. Nevertheless, Bergen-op-Zoom, Mannheim, and other places fortified by this engineer, particularly the two named, have very great merit, inasmuch as it is impossible for a besieger to penetrate into any of the works without being exposed, on all sides, to the fire of the besieged, who are under cover, and from whose artillery and musketry fire it is scarcely possible for an assailant to shelter himself. In fact, Coehorn was a great master, and combined with the bastioned trace, as will be explained when his system is noticed, many of the means of defence springing from another source. He published his first work on Fortifica tion before he had acquired much experience ; and in forti fying Bergen-op-Zoom, which is allowed to be his master piece, he did not reproduce, except in fragmentary details, any of his published systems. Since Vauban s time several improvements have been suggested, particularly by Cormontaigne, who entered the corps of French engineers in 1716, nine years after Vau ban s death, and died a mareschal-de-camp in 1750. Some ! account of the system of Cormontaigne will be found in ! a subsequent part of this article. The three methods enunciated by Bclidor are all applicable to an octagon of 200 toises. Scheiter distinguished his systems as great, mean, and little, in imitation of Pagan, requiring the ex terior sides of the polygon to be 200, 180, and 160 toises re spectively. He adopted from Castriotto detached bastions, and made use of a continuous fausse-braye. Fritach, a Pole, proposed two methods, which he exemplified on different polygons. Dogen, a Dutchman, after enumerating, in a large volume on Fortification, various modes employed by different writers for determining the salient angle, selected three as most worthy of approval, and proposed as many methods of construction, one of which is borrowed from Fritach, the Pole. Pietro Sardi, an Italian, suggested a j peculiar method of construction on a hexagon. The Sieur de Fontaine found the flanked or salient angle of the bas tion by adding 15 to half the angle of the figure, from the square up to the dodecagon, in which last it becomes 90, and at this he continued it in all the higher polygons. He also constructed outwards, and, in every regular figure, made the curtain equal to 72 toises, the face of the bastion to 48, and the flank, which he placed perpendicularly to the curtain, to 18 toises, or a fourth part of the curtain. Ozanam and Miiller delivered each four methods of construc tion, the particulars of which will be found in their respec tive works. In 1751 Charles Bisset, who, as engineer- extraordinary, served with the duke of Cumberland in the Netherlands, and was present during the siege of Bergen- op-Zoom by Marshal Lowendahl, published a treatise on th i theory and construction of Fortification, in which there are many sensible and judicious remarks; and this may also be said of an Essai sur la Fortification^ ou Examen des Causes de la grande superiorite dc I Attaque sur la Defense, published anonymously in 1755. In a work entitled Science de la Guerre, which appeared at Turin in 1747, a new method of construction is proposed, in which the principal novelties are mines under all the works, and regular communications with them by means of subter raneous galleries, to be resorted to as the enemy ap proaches the body of the place. The third volume of the (Euvres Militaires contains useful observations and maxims relative to irregular Fortification ; and in the supplement to the Reveries of Marshal Saxe, by Baron d Espagnac, the subject of Fortification is amply discussed, and an accurate description given of the different means of attack and defence. Besides the writers above enumerated may be mentioned the Chevalier St Julien, an able engineer, who published a method by which, he asserts, works may be constructed at less expense, yet in such a manner as to render the defence more formidable ; Francisco Marchi, of Bologna, who in 1599 furnished no less than 139 different methods of constructing fortifications, many of which arc valuable, and from which subsequent engineers have greatly profited ; Bombelle, who established three kinds of Fortification, called the grand royal (grand royal), the mean royal (moven royal), and the little royal (petit royal); Blondel, who published a system divided into two principal heads, the great and the little, whose exterior sides are re spectively 200 and 1 70 toises ; Donato Rosetti, a canon of Leghorn, who wrote on the method of constructing works in what he calls Fortification a relours, or Fortification in re verse, so denominated because the re-entering angle of the counterscarp being opposite to the flanked angle, it will, ac cording to him, be necessary to attack it from the reverse side of the other works ; and Antonio de Herbart, major of artil lery in the duke of Wiirtemberg s service, who published a treatise on Fortifications with what he calls angular poly gons. The treatise entitled Nouvelle Mamere de fortifier les Places, tiree des mvtJiodes du Chevalier de Ville, du Comte de Pagan, et de M. Vauban, avec des Remarques sur I ordre renforce, sur les desseins da Capitaine Marchi, et sur ccux de M. Blondel, which appeared in 1689, is full of strong reasoning, whence the author deduced a new system ; but it contains little that is original, though it gives numer ous references to what had previously appeared, and dis poses the different parts in a judicious manner. M. de Montalembert s system of casemated and reverse fire has been in part adopted in the splendid fortress of Alessandria, in Italy, which was constructed under the direction of Napoleon. Of the more recent treatises on fortification, that of M. de Bousmard, entitled Essai General de Fortification, d At- taque et de Defense des Places, dans lequel ces deux Sciences sont expligniees et mises I une par Caiitrc & la portee de tout le monde, is very elaborate and complete, and enjoys a de servedly high reputation for accuracy and research. Carnot s Traite de la Defense des Places Fortes was written to serve a temporary purpose ; and the exaggerated celebrity which it acquired on its first appearance has been succeeded by an equally unfounded neglect. The more prominent innovations recommended in this treatise were first, an alteration, which, however, was not original, in the trace or outline of the polygon ; secondly, the suppression of the exterior revetment of the covered-way, known as the counterscarp ; thirdly, the detachment of the escarp- wall from the rampart, and the construction of the latter without revetement; fourthly, destructive personal con flict with the besiegers by means of frequent sorties ; and, lastly, vertical fire as the basis rather than the accessory of the defence. With regard to these innovations, all of which the reader will find ably discussed in Jones s Journals of Sieges in Sjxiin and Portugal, vol ii., it may be remarked that by means of an increased expenditure for retrench ments and casemates, as recommended by Carnot, the strength of particular portions of the polygon may be in creased ; and that, if he has failed in tracing a perfect front, founded on the basis of Montalembert s system of casemated and reverse fire, he has at least rescued a valu-