Roman see, Formosus wrote to Arnulph, king of Germany, | mind of Forskal, and is far in advance of the works of a inviting him to come to Italy and assume the crown. Ar- similar kind published by the followers of Linnæus. It is nulph came to Italy and was crowned at Rome by Formosus one of the first books in which the relation of vegetation to in the beginning of the year 895, after the death of Guido. climate is taken as a great object of consideration, and may The history of that period and of the various competitors to in fact be quoted as one of the earliest steps made in geothe crown of Italy is extremely confused. Formosus died graphical botany. We here find an attempt to show the in April, 895, and was succeeded by Boniface VI., who, existence of geographical parallels of vegetation, and the dying a few days after, was succeeded by Stephen VI., by remarkable assertion that, Given the specimens of plants, some styled the VII., who having taken the part of Lam- you may find the latitude of a country, the elevation of its bert against Arnulph, instituted proceedings in a council surface, and the zones of vegetation upon its mountains. against the memory of Formosus, and had his body disin- from their foot to their highest peaks.' The 'Flora Ægypterred. Romanus however, who succeeded Stephen, in a tiaco-Arabica' is to this day the only good account we have council held at Rome, in 898, rescued the character of For- of the plants of those countries, and it may be even doubted mosus from this stigma, had his body honourably buried whether we have upon the whole so satisfactory a view of again, and declared the acts of his pontificate to be legal and the vegetation of any extra-European region. We have valid. 'Floras' with more systematic learning; we have works FORNAX (Constellation), the Chemist's Furnace, one much more complete in their details, more technical, more of the southern constellations of Lacaille. It is situated laboured, more diffuse, prepared with all the advantages of immediately below Cetus. leisure, experience, and the resources of rich herbaria; but if the botanist is asked to point out one as philosophical, as well contrived, as useful, as rich in valuable observations upon climate, air, soil, native names, and similar important matters, we know not to what other he could refer. Linnæus fixed the name of Forskal to his own Caidbeja adhærens, a worthless Arabian weed, under the title of F. tenacissima; but we are assured by a panegyrist of the great Swedish botanist, that in doing so he intended to compliment rather than satirize the character of his unfortunate countryman. No. in Catalogue of Magnitude. 99965 (73) 246 5 FORSKAL, PETER, a celebrated naturalist and orien tal traveller, was born in Sweden, in the year 1736. After studying at Göttingen, where he published a dissertation under the title of Dubia de Principiis Philosophiæ recentioris,' by which he gained some credit, he returned to his native country. In 1759 he wrote his Pensées sur la Liberté Civile, a pamphlet which did not prove agreeable to the ruling powers of Sweden. A fondness for natural history had brought him acquainted with Linnæus, then at the zenith of his fame, by whom he was favourably recommended to Frederick V., king of Denmark. In 1761 he obtained the title of professor at Copenhagen, and having been distinguished for his acquaintance with oriental languages, he was selected to join Niebuhr and others in an expedition to investigate Egypt and Arabia. After visiting Marseilles, Malta, some of the Greek islands, and Constantinople, he arrived at Alexandria. For about a year he remained stationary in Cairo and its vicinity; he afterwards visited Suez, and entering Arabia by Loheia, he penetrated by way of Beit el Fakih and Zebid as far as Mocha; thence crossing the mountains to Taas and Abb, he eventually and with difficulty reached Jerim, where he died on the 11th of July, 1763. In the course of this journey, although robbed and ill-treated by thieves near Alexandria and elsewhere, suffering from constitutional timidity, and often bowed down with sickness, he investigated with such extraordinary energy and perseverance the natural productions, especially the plants, of the places he visited, that although he never lived to arrange his papers, the account of the vegetation of Egypt and Arabia, compiled after the return of his companions to Europe, is a model of the manner in which such investigations should be conducted. From his friend and companion Niebuhr, to whom the care of editing Forskal's MSS. was intrusted, we have a Fauna Orientalis,' under the title of 'Descriptiones Animalium, Avium, Amphibiorum, Piscium, Insectorum, Vermium, quæ in itin. orient. observavit Petrus Forskal,' 1775, 4to.; and in the same year and form appeared a Flora Ægyptiaco-Arabica,' or an account of the plants found in Lower Egypt and Arabia Felix. This latter work is very remarkable as an illustration of the philosophical FORSTER, JOHN REINHOLD, was born in 1729, at Dirschau in Western Prussia, of which town his father was burgomaster. Having studied at Halle, he was appointed in 1753 to the cure of Vassenhoff near Danzig. In 1765 he accepted an offer to go to Russia to take the direction of the new colony established by Catherine at Saratof; but he soon left it in disappointment, and proceeded to England in 1766, where he became known to Mr. Banks and others for his acquirements in natural history. During his residence in England he employed himself for some years as teacher in a Dissenters' school at Warrington in Lancashire. Through Mr. Banks's interest he was appointed naturalist to the second expedition under Captain Cook, and he sailed, together with his son George, on board the Resolution, in July 1772. A sum of 4000%. was granted by parliament for his expenses, besides which it was verbally understood between him and the Honourable Daines Barrington, in the name of Lord Sandwich, that Forster should be employed on his return to write the history of the voyage, and receive the profits of the publication. In the course of the voyage repeated disagreements took place between Forster and the officers of the expedition, and Captain Cook himself appears to have censured Forster's indiscretion and want of temper. After the return of the expedition in July 1774, a controversy arose between Forster and Lord Sandwich about writing the narrative of the voyage. It was at last settled that Forster should write the philosophical, and Cook the nautical parts of the work. Forster's MSS. were to be subject to Barrington's correction; but on presenting a specimen of his intended work, he was told that he must not write a connected narrative but only detached observations, and ultimately even these were rejected. The consequence was that Cook's journal appeared alone. Meantime Forster, the son, published a separate account of the voyage in 1777; a circumstance which indisposed the Admiralty still more towards his father, who was believed to have had the principal share in the work, and who thus lost all hopes that he might have entertained of remuneration. Forster's account of the transactions is given in the letters of his son George to Lord Sandwich, and to Mr. Wales, who had written strictures on Forster's narrative. In 1778 Forster returned to Germany, and was well received at Berlin by Frederic the Great, and was soon after made professor of natural history and mineralogy at Halle, where he remained till his death, in December, 1798. Forster was a man of vast information both in the natural sciences and in philosophy, and general literature. His principal works are -1. De Bysso Antiquorum, 1775;' 2. Characteres Generum Plantarum quas in insulis Maris Australis collegit J. R. Forster,' 4to., 1776; 3. Observations faites dans un Voyage autour du Monde, sur la Géographie physique, l'Histoire Naturelle, et la Philosophie Morale,' 4to. 1778. This work was translated into various languages, and forms a good supplement to Cook's journal, although the tone of Forster's observations is not always in accordance with sound criticism. 4. Zoologia Indica,' | 1781; 5. Histoire des Découvertes et Voyages faits dans le Nord, 1784; 6, Tableau de l'Angleterre pour l'année 1780,' a satirical work written under the influence of disappointment and animosity, and consequently with little discrimination. FORSTER, JOHN GEORGE, son of John Reinhold Forster, accompanied his father in the voyage with Captain Cook, and published an account of the same in 1777, which involved him and his father in an unpleasant controversy. This narrative does not differ materially in the facts from Cook's journal. Forster however has added to his work various observations, which he considered as philosophical, but which are often only declamatory. His book was translated into German, French, Swedish, and other languages. Forster having returned to the Continent, was made professor of natural history at Cassel, and afterwards at Wilna, from which last place he returned to Germany about 1788, and was appointed librarian to the elector of Mayence. After the French took Mayence in 1792, Forster, who had become enthusiastic in the cause of the Revolution, was chosen by the republicans of that city to proceed to Paris, as their representative, to request the incorporation of Mayence with the French republic. While he was at Paris on this mission, the Prussians re-took Mayence, and Forster lost all his property, including his books and MSS. This loss, and other domestic disappointments, made him resolve on leaving Europe, and he planned a journey to India and Tibet, preparatory to which he applied himself to the study of the Oriental languages; but he fell ill soon after, and died in January, 1794. He left several works; among others, Ansichten von Nieder Rhein, von Brabant, Flanders, Holland, England, und Frankreich in 1790,' in three parts, of which the last was published after his death, Berlin, 1794. This work was translated into French under the title of Voyage Philosophique et Pittoresque sur les Rives du Rhin, &c.,' 3 vols. 8vo., Paris, 1795-6. The last volume contains an essay on the history of the fine arts in Great Britain. Forster wrote also 'Herbarium Australe,' several memoirs on natural history, and various political and philosophical sketches and pamphlets. FORSTER, GEORGE, a civil officer in the service of the East India Company, is chiefly known by his journey in 1782 over-land from India to Russia. He set off from Lucknow in December, 1782, and directed his route to the north by Ferahabad, Rampoor, and by the pass of Lall Dong into the upper regions of the Punjab, avoiding the country of Lahore, which was possessed by the Seiks. He then proceeded by Bellaspoor and Jombo into the great alpine valley of Cashmere, which had not been visited by any European travellers before him, Bernier excepted. Forster's account however proved much more full and satisfactory than that of Bernier. Quitting Cashmere, Forster proceeded to Cabul, crossing the Indus about twenty miles above Attock. From Cabul he followed the caravan road to Candahar, and thence by Herat to the southern coast of the Caspian Sea. From Oude to the Caspian he was nearly twelve months on his journey, the distance being 2700 miles, amidst all sorts of dangers and privations, which were much greater at that time than they would be at present. He embarked at last at Meshed Ser on the Caspian, and sailed from thence to Baku and Astrakan, from which last place he travelled to Moscow and Petersburg, where he arrived at the end of May, 1784. On his arrival in England he published some sketches of Hindoo mythology. He afterwards returned to India, and published in 1790 at Calcutta the first volume of his narrative-Journey from Bengal to England through the most northern parts of India, Kashmere, Afghanistan, and Persia, and into Russia by the Caspian Sea. On the commencement of hostilities with Tippoo Sultan, Forster was sent as envoy to the Mahratta court of Nagpore in Deccan, where he died in 1792. The MS. of the sequel of his journey was sent to England, where it was published by a bookseller in a second volume, but was edited without much care. The whole work was translated into French by Langlès: Voyage de Bengale à Petersburg,' 3 vols. 8vo., Paris, 1802. Forster added to his narrative two interesting notices of the Seiks and the Rohillas. FORSTERITE, a crystallized mineral, the primary form of which is a right rhombic prism. The crystals are colourless, translucent, brilliant, and small; they are harder than quartz. This substance occurs at Vesuvius accompanied by pleonaste and pyroxene. It has not been accurately analýzed, but contains silica and magnesia FORT, LE. [LEFORT.] FORT ROYAL. [MARTINIQUE.] FORTE (Italian strong, loud), a musical term, directing the performer to sing or play loudly, with strength. Fortissimo is the superlative of Forte. FORTESCUE, SIR JOHN, KNT., an eminent lawyer, lord chief justice of England in the reign of Henry VI, and afterwards chancellor. He was the author of a treatise De Laudibus Legum Angliæ;' a work which has been several times quoted with the highest approbation from the bench, illustrated by the notes of Selden, and recommended by such writers as St. German and Sir Walter Raleigh, in former times, and by every writer who has since given directions for the study of the law. It has been several times translated into English. It is in the form of a dialogue between himself and the young prince Edward, with whose education he appears to have been intrusted. The author undertakes to show that the common law was the most reasonable and the most antient in Europe, and superior to the civil law and the laws of other countries. He considers at length, in particular, the mode of trial by jury; and after examining some other points of difference between the civil and the common law, he concludes with a short account of the societies where the law of England was studied. This book, as well as the other works relating to English law of an early date, is written in a bold style, and displays many sentiments upon liberty and good government, which are very remarkable, considering the fierce and barbarous period at which they were written. We cannot,' says Chancellor Kent, but pause and admire a system of jurisprudence which, in so uncultivated a period of society, contained such singular and invaluable provisions in favour of life, liberty, and property as those to which Fortescue referred. They were unprecedented in all Greek and Roman antiquity, and being preserved in some tolerable degree of freshness and vigour amidst the profound ignorance and licentious spirit of the feudal ages, they justly entitle the common law to a share of that constant and vivid eulogy which the English lawyers have always liberally bestowed upon their municipal institu tions.' The English translation of the treatise De Laudibus Legum Angliæ,' and the original Latin text, together with some notes by Mr. Amos, were published in 1825 at the expense of the University of Cambridge. (Kent's Comms. Reeve's Hist. Eng. Law.) FORTH, a river in Scotland, which rises in the mountains separating the western extremity of Loch Cateran or Katrine from Loch Lomond. It is formed by two branches, which after a course of sixteen and twelve miles respectively, unite at Aberfoyle: this united river receives the name of Forth. At Aberfoyle the river issuing from between the mountains, enters a wide valley, which is surrounded by hills rising to a moderate elevation and generally with a gentle slope. From the north it is joined by three tributaries of some note, the Teith, which drains the mourtainous country north of Loch Cateran, the Allan, which runs through Strathmore, and the Devon, which brings down the water collected in the greater portion of the Oehill Hills. No considerable river joins it from the soul.. At the place where it unites with the Devon, the river. which higher up is only a stream of moderate size, begir:s to widen, and gradually assumes the appearance of a gulf especially after having passed Kincardine. This gulf, called the Frith of Forth, increases in width in its progress to the east, and joins the North Sea between Fifeness and the rocks of Tantallan Castle, where it is about fifteen miles across. The source of the Forth is not much more than thirty miles from the mouth of the Devon in a straight line, but as it flows in the valley with many sinuosities, its real course is stated to exceed considerably twice that length The length of the Frith from west to east rather exceeds fifty miles. The Forth is by no means a rapid river below Aberfoyle, and may be navigated by vessels of seventy tonburden as far as Stirling; but as its course is extremeis tortuous between Stirling and Alloa, it is not much nav.gated in this part. To Alloa, which may be regarded as i principal port, ships of 300 tons burden may ascend. On the southern shores of the firth, near the mouth of the river Carron at Grangemouth, the canal commences, which joins the Forth and the Clyde; and contiguous to it on the east, between Grangemouth and Queensferry, is good and 38cure anchoring ground in the bay. The countries along the northern and southern shores of the Frith comprehend the most fertile and best cultivated parts of Scotland. (MacCulloch's Highlands, &c.; Sinclair's Stat. Account.) FORTIFICATION is the art of constructing works for the protection of a town or military position. The principles which regulate the general plan of the works constituting the fortifications of a town or great military post, have at all times been nearly the same. Among the antients, with scarcely any exception, the polygonal wall surrounding a place was provided with towers projecting from it at intervals towards the front; and a barbacan, or outwork, consisting of two or more towers, connected by walls like those of the fortress itself, was generally constructed on the exterior side of the ditch and opposite a gate of the town, in order to protect that entrance and the bridge leading to it. The towers and walls about an antient town correspond to the bastions and curtains forming the enceinte of a modern fortress, and the barbacan may be considered as the counterpart of its ravelin, or principal outwork. The necessity which the nations of Europe were under of remodelling their fortified towns in consequence of the change produced in the art of war by the invention of gunpowder, gave occasions for the engineers of Italy, France, and the Netherlands to emulate each other in devising the most advantageous methods of disposing the works for the purposes of defence with relation to the arms then newly introduced; and the result of their labours was the construction of numerous strong fortresses on the frontiers of those countries. In these the bastion system, as it is called, was invariably adopted; and it is remarkable that, of the very numerous projects which have been since offered to the world for fortifying places, so few should have been of a different kind. The variations however which occurred in the details of the plans gave rise to the denominations of the Italian, the French, the Spanish, and the Dutch methods, in speaking of the works proposed or executed at the end of the sixteenth and the beginning of the seventeenth centuries; but it must be observed that those variations consisted chiefly in the magnitude of the angle which the two faces of a bastion made with each other, and in the extent of what was called the second flank; that is, the portion of the curtain then generally left between the flank of a bastion and the place where the produced face of the collateral bastion intersected the curtain. The first bastioned fortresses of France appear to have been very inferior to those which were executed in the Netherlands by the Italian engineers; and there still exist some remains of these last in which the bastions are sufficiently capacious, and at distances from each other within the effective range of musket-shot. The others, on the contrary, were characterized by small bastions, scarcely capable of receiving artillery, and placed so far asunder as to defend each other very imperfectly. But after the termination of the civil wars which desolated the country, the attention of the French government was directed to the state of the military posts; and Errard, a member of the corps of engineers then instituted, was appointed to superintend the reparation of the old, and the construction of the new fortifications. The citadel of Amiens was built according to the plan proposed by this officer, who, in 1594, published a treatise on fortification, in which some effort is made to determine the principles which should regulate the forms and dimensions of the works. In the method proposed by Errard the bastions are much larger than those of the earlier time, the length of their faces being, as at present, about one-third of the distance between the salient angles of two collateral bastions; an orillon occupied nearly two-thirds of the length of each flank, which was very short, and formed an angle of about 80° with the curtain. This direction appears to have been given to the flanks in order that the guns behind their parapets might be as much as possible concealed from the view of the enemy in his counter-battery; but it is evident that the defenders of the opposite flanks, laying their muskets perpendicularly to the lengths of the parapets, accordng to the general practice, would almost inevitably fire upon each other, or upon those who were stationed on the curtain. De Ville, who composed a treatise on fortification in 1629, made several improvements on the method proposed by Errard, the principal of which were an augmentation of the length of the flanks and a perpendicular direction of the latter with respect to the curtain: by these changes a better defence was obtained from the flanks, and the evii above mentioned was diminished. But a still greater amelioration was made by Count Pagan, who, in 1645, proposed to make each flank [See the half-front of Fortification between Fand G, fig. 1, BASTION] perpendicular to the produced face of the collateral bastion: the reciproca. defence which the works should afford each other is thus complete, and the men are not in danger of being fired on by each other. Pagan retains the orillons at the shoulders of the bastions, and he gives to the latter double or triple flanks; but the construction of these, on account of their numerous inconveniences, has ever since been discontinued. During the reign of Louis XIV. a general reparation or reconstruction of its fortresses was ordered by the French government; and the talents of Vauban were exercised in devising and carrying into execution those improvements in the art of fortification which, together with the merit displayed in the conduct of fifty-three sieges, have given that engineer so much celebrity. Besides the changes made in the disposition of the parts of the enceinte, the outworks were entirely remodelled; and instead of assigning, for the delineation of the plan, numerous arbitrary rules which varied with the nature of the polygon, Vauban adopted the length of the side of the polygon as a base, and took certain aliquot parts of this line for the dimensions of the several divisions of the rampart; thus reducing the construction to a few simple precepts which were applicable to places of all magnitudes. These precepts being founded on the uses of the works may be justly considered as constituting a system of fortification; and from that time to the present scarcely any deviations have been made from them in the construction of great fortresses. A brief outline of the system will therefore be here given. [See the half-front of fortification between G and E, fig. 1, BASTION.] The length of each side, as FE, of a regular polygon supposed to surround the town or position, is made equal to 360 yards, in order that all the parts of the rampart on each front of the enceinte might be within the range of the arms employed in the defence. Those arms are generally large muskets, whose point-blanc range is estimated at about 300 yards. Now these being supposed to be placed on the flanks, as at e or f, might be employed to oppose the formation of the counter-battery at H, or at the corresponding point on the left of F; therefore, if we assume the length of the line from e to H to be 300 yards, and deduct from it the estimated breadth of the main ditch and coveredway (40 yards), we have 260 yards for the length of e E or f F, which is called the line of defence. This is also the distance of E or F from the shoulder of the collateral bastion; and if we add to it the length of the face of the bastion, which is 103 yards, or two-sevenths of E F, in order that, in the inferior polygons, the bastion may have sufficient capacity, we obtain about 360 yards for the distance between the salient points F and E of the two bastions; and it may be observed, that a few yards more or less in the dimensions need not be regarded. The directions of the faces of the bastions on each front coincide with lines drawn from the angles E and F of the polygon, through the extremity of a perpendicular let fall from the middle of the line EF and made equal to onesixth of that line; and each flank is the chord of an arc, described either from the opposite angle E or F of the polygon, or from the nearest shoulder of the collateral bastion, as a centre. By this construction the flank is rather greater in length than the enemy's counter-battery, which is necessarily limited by the angle of the glacis and the prolonged face of the nearest bastion; and it is nearly perpendicular to the direction of that face: the reason why it is not made exactly so is, that a man on the flank, placing his musket perpendicularly to the line of parapet, will thus be able to fire into and defend a breach which may be made in the face of the collateral bastion. The curtain is determined by a line joining the interior extremities, near e and ƒ of the flanks; and, with the height, which Vauban assigned to the rampart of the enceinte, this length will permit the fire of musketry from each flank to defend the opposite half of the ditch between the flanks. The line which on the plan indicates the directions of the faces, flanks, &c., of the works, is called the magistral line; it forms the exterior side of the ramparts in fig. 1 [BASTION], and coincides with the cordon, or projection, at the top of the revetment N, fig. 2. The dimensions of the ditch are determined by the ne- | towers, or orillons, containing casemates. In the interior cessity of obtaining from it the earth for the formation of of each bastion is another, on a higher level, and on the the ramparts and parapets, care being taken that it be not exterior is a counterguard, or detached work, consisting of so wide as to allow the enemy, from a battery situated as at two faces. A large ravelin, inclosing a smaller one on a K, fig. 1, on the crest of the glacis, to see, and consequently higher level, is placed before the curtain, and the whole is to batter, the escarp wall near the foot of the latter. surrounded by a broad covered-way, whose places of arms [BREACH.] The counterscarp wall is rounded opposite the are retrenched by brick redoubts. The ditches are full of flanked angles at E or F, and from thence tends towards the water; and the terrepleins, as well of the bastions and shoulder of the collateral bastion. ravelins as of the covered-way, are sunk below the natural surface of the ground, so that it would be impossible, in the marshy soil on which the fortifications are supposed to be constructed, for an enemy to dig trenches there in order to form covered approaches. The terrepleins of the principal works are also well defended by fire from the covered galleries which cross them, or which are formed within the masses of the ramparts. The improvements made by Vauban in the ravelin are described under that word: Q represents one-half of that work; and it will be necessary here to say, merely, that its plan is determined by using the angular points near e and f, formed by the magistral lines of the flanks and curtain, | as centres, and with radii equal to the distances from thence to points taken on the faces of the collateral bastions, at 10 yards from their shoulders, describing arcs; the intersection of these arcs determines the salient angle of the ravelin; the magistral lines of its faces tend from that intersection to the points just mentioned, and terminate on the counterscarp of the main ditch. The traverses in the covered way were proposed by Vauban, in order to diminish the effect of the ricochet; and he was the first engineer who formed the spacious places of arms, as they are called, at L, in the re-entering parts of the covered-way, in order to obtain room for assembling troops, and to afford a good crossing fire of musketry from their faces for the defence of the glacis in front of the bastions and ravelins. An attention to the reliefs of the several ramparts of a fortress is no less necessary than to the plans; for, as it would be advantageous, when the approaches of the besiegers are near the foot of the glacis, that a fire of artillery should be made from the ramparts of the enceinte or ravelin, and of musketry from the covered-way at the same time, the reliefs of those ramparts should be determined by imagining a line to be drawn from the foot of the glacis through a point three or four feet vertically above the crest of the latter, that is about 11 feet above the ground, and to be produced through the parapet of the said enceinte or ravelin; then, if the soles of the embrasures, which are necessarily 4 feet below the crest of the parapet, be made to coincide with such imaginary line, the fire of artillery from them may be directed to the enemy's trenches without incommoding the defenders of the covered-way. The crest of the enceinte thus determined will be about 18 feet above the ground, and that of the ravelin about 3 feet less. The tenaille, P, fig. 1, [BASTION,] will be described under that word; but it may be mentioned here that the relief of this work is determined by the consideration that, while it should be high enough to mask the postern in the curtain behind it, the men stationed on it to defend the ditch should be below the lines of fire from the flank of one bastion, when directed to the foot of a breach supposed to be made near the shoulder of that which is collateral to it, in order that they may not be injured by that fire. As Vauban had occasionally to adapt works constructed according to the principles above mentioned, to the old fortifications which then existed, the particular method employed in disposing them acquired the denomination of his second system; and when, subsequently, he fortified Neu Brisach, some few modifications which he was led to make gave rise to a new distinction, the works of that place being considered as forming a third system. In both these systems the bastions V, fig. 3, [BASTION] are separated by a ditch from the enceinte; and this circumstance is so far advantageous, that the place would not be compelled to surrender immediately upon those works being taken by the besiegers. The enceinte consists of a long curtain, either quite straight or broken by two short flanks; and at the angles of the polygon are small bastion-towers of masonry (T, fig. 3), in whose flanks are formed casemates to contain artillery for the defence of its ditch. This great engineer died in 1707, at the age of 74 years; and, from .his time, the French fortification has been that of all Europe. It would be improper in this place to omit the name of Coehorn, who was a contemporary of Vauban, and who is also distinguished by the invention of three methods of fortifying places; of which however the first only, and that partially, has been put in execution. The outline of the plan differs but little from that of his rival's first system, but the shoulders of the bastions are strengthened by large It should be observed that the salient points E, F, &c., of the bastions and ravelins in Vauban's system being nearly equally distant from the centre of the place, the trench executed by the besiegers to connect the glacis before the former works will also connect that which is before the latter; and that, in consequence of this construction, breaches may be formed, and assaults made, at one time, in the enceinte and outworks. With the view, therefore, of preserving the former untouched till some time after the ravelins may have been taken, the French engineer Cormontaingne proposed, about 30 years after the death of Vauban, to advance the salient points of the ravelins as much as possible, by increasing the length of the faces to the utmost limit which a regard to the due magnitude of the flanked angle will admit. Thus the magistral line of his ravelin is determined by the sides of a triangle whose base is a line joining two points on the faces of the collateral bastions, at 30 yards from the shoulders, and whose opposite angle is equal to about 70 degrees. By this construction at would become impossible for an enemy to crown the glacs of a bastion till he had got possession of the two collater ravelins, on account of the fire which, from these, might be made upon his approaches between them; and the fall of the place would be delayed by the time spent in conducting the approaches from the ravelins to the intermediate bastion. In order that this benefit might be obtained in the highest degree, Cormontaingne suggested the propriety of fortifying places on polygons of the superior kind, and even, when possible, of constructing two or more fronts of fortification on one straight line; this practice would have the additiona advantage of rendering the flanked angles of the bastions very obtuse, by which, not only would the increased capacity of those works permit stronger retrenchments to be formed in them, but the faces being produced outwards, would tend to points on the faces of the ravelins, and thus would be cotapletely secured from the enfilading fires of the besiegers. Besides the above general modifications, Cormontaing made several improvements in the details of the works. He made the flanks exactly perpendicular to the prolonge faces of the collateral bastions, for the sake of a more e plete flanking defence. He made the terrepleins of the ravelins merely wide enough to contain the artillery of the defenders; in order to increase the capacity of the redou in the ravelin, and to deprive the enemy of the space necessary for a battery on the ravelin, by which he might brear. that redoubt. He also gave large casemated flanks to the latter work, in order that a powerful fire might be directed from them against the enemy, if he should attempt :mount the breach in the face of either bastion before had got possession of the redoubts as well as of the ravelte themselves. A further improvement was made by the engineer in adding to each of the re-entering places of arc a spacious redoubt, which would render the defence of tha place more obstinate, and cover the passage between the tenaille and the flank of the bastion. As early as 1640, Dillichs, in a work published at Frank fort, proposed a method of fortifying places, which cons in surrounding them by lines of rampart forming with e. other a series of angles alternately salient and re-enterin and, subsequently to the time of Vauban, a few other; jects of a like nature have been suggested. The E remarkable of these is that which was published in 1775 the French General Montalembert, who entitles his me Fortification Perpendiculaire. Its outline on the plan > series of the sides of equilateral triangles formed on the of a dodecagon inclosing the place; the re-entering ang being consequently right angles and, as the general has During the existence of the French empire, the celebrated Carnot proposed to restore the balance between the attack and defence of fortresses, which the inventions of Vauban had made to preponderate greatly in favour of the former, by means of powerful sorties from the place and an abundant discharge of stones and balls from mortars fired at considerable angles of elevation; thus annoying the besiegers in their trenches, and either putting great numbers of their men hors de combat, or compelling them to recur to the slow process of blinding their approaches. Adopting, in his method of fortifying places, the proportions of Cormontaingne for the plan of his bastions, but making the whole length of his front of fortification equal to 480 yards, he detached the bastions from the enceinte, which he made to consist of a simple polygonal rampart of earth In real of the tenaille between the bastions he placed a faussebraye, whose exterior side was to be protected by a case mated tower at each extremity; and, behind the gorge of each bastion, he formed a row of casemate vaults, in which the mortars were to be placed for throwing stones, &c. into that work when gained by the enemy. Adopting also the ideas of Montalembert respecting detached walls, he proposed to surround the enceinte by one, which was to be loop-holed in order that a fire of musketry might be made from it, and to construct a similar wall before the faces and flanks of the bastions. The bastions were to be covered by narrow counterguards; a cavalier, or lofty redoubt, in front of the tenaille, was to defend the collateral faces of both bastions and counterguards; large ravelins were to cover the central parts of the fronts of fortification and afford crossing fires on the ground before the bastions; while mortars placed on the faces of the work and on the barbettes at the angles were to discharge their missiles over the parapets. A ditch surrounds the whole, and its exterior side is made with a gentle slope from the bottom to the level of the natural ground in front, for the purpose of facilitating the sorties; the corresponding facility which the enemy might have for descending into the ditch being dis regarded on account of the supposed impossibility of maintaining himself there under the hail of stones and shot from the works. It was supposed that the detached wall, being covered as before mentioned, would present an impassable obstacle to the assailants; but an experiment made at Woolwich in 1824 has proved the possibility of breaching it by a fire of shot and shells, directed over the parapet of the counterguard, from artillery of great calibre, at the distance of 400 yards from the latter work. The efficiency of the vertical fire, as it is called, of stones and shot from the works has also been controverted; and experiments have been made which seem to prove that the momentum acquired by the missiles in their descent would not be sufficient to do serious injury to a man on whom they might fall, if he were pro tected by a proper head-piece. Plan of a Front of Fortification according to the Method of Cormontaingne. A Boid Baston. B, Hollow ditto. X, Retrencament. P. Tenaille. G, Caponniere. QQ, Ravelin, Y, Redoubt in ditto. L L, Ke-entering places o Arms. WW, Redoubts in ditto. RR, Covered-way. tt, Traverses. SS, Glacis. 7. Barbette battery. P. C., No. 642. VOL. X.-3 C |