frame which carries the forge-hearth, and connected with the frame is a system of shafts, speed-wheels, pinions, &c., to move the piece of metal which is to be acted on, and also the hammer. There is a blowing-fan making sixteen hundred revolutions in a minute. The boiler for the steam-engine is over the hearth. The forge-anvil is placed by itself on the floor, at the other end of the machine. The hammers are attached to levers on a horizontal shaft in the hearth-friend of mine, one M. Laurence Whitaker, who, in his merry humour, frame, and are set in motion by the steam cylinder, through the medium of a long sliding rod which strikes the tail of the lever or levers. Hand-gear is provided for working the hammers if steampower should not be available. FORGERY is the false making, counterfeiting, altering, or uttering any instrument or writing with a fraudulent intent, whereby another may be defrauded. The offence is complete by the making the forged instrument with a fraudulent intent though it be not published or uttered, and the publishing or uttering of the instrument, knowing it to be forged, is punished in the same manner as the making or counterfeiting.

It is by no means necessary to bring the offence within the legal meaning of the term forgery, that the name of any person should be counterfeited, though this is the most common mode in which the crime is committed; thus a man is guilty of forgery who antedates a deed for the purpose of defrauding other parties, though he signs his own name to the instrument; and the offence is equally complete, if a man being instructed to make the will of another, inserts provisions of his own authority. In truth the offence consists in the fraud and deceit.

At common law the crime of forgery was only a misdemeanour, but as the commerce of the country increased and paper credit became proportionally extended, many severe laws were enacted, which in most cases made the offence a capital felony.

The extreme severity of these laws tended to defeat their object, and parties very frequently chose rather quietly to sustain the loss inflicted upon them by the commission of the offence, than by a prosecution to subject the offender to the loss of life. This feeling, and the diffusion of the truth, that the object of all laws is to prevent crime and not merely to punish, has caused successive mitigations in the laws relating to forgery, and now by various statutes, particularly the 11 Geo. IV., and 1 Will. IV. c. 66; 2 & 3 Will. IV. c. 59, and 1 Vict. c. 84, the punishment of death is abolished in cases of forgery, and a punishment varying between transportation for life (now penal servitude) and imprisonment for one year is substituted.

(1 Hawk, P. C.: Russell on Crime; Deacon's Criminal Law.) FORK (Anglo-Saxon fore; the same as the Latin furca), an instrument divided at the end into two or more prongs for various uses, especially for the table. Addison speaks of a thunderbolt with three forks. It is sometimes used for an arrow, and in old English for a gallows or gibbet. Butler, in his 'Remains' (ii. 195), says, "They had run through all punishments, and just 'scaped the fork." The furca was an instrument of punishment among the Romans. Criminals convicted of serious crimes were fastened to it and then scourged to death; but it was also used for slighter punishments, and for some offences slaves were condemned always to carry it about with them: hence the use of the word "furcifer" as a term of reproach.

Italian cannot by any means endure to have his dish touched with fingers, seeing all men's fingers are not alike clean. Hereupon I myself thought good to imitate the Italian fashion by this forked cutting of meat, not only while I was in Italy, but also in Germany, and oftentimes in England since I came home: being once quipped for that frequent using of my fork, by a certain learned gentleman, a familiar doubted not to call me at table furcifer, only for using a fork at feeding, but for no other cause." Coryate's testimony is confirmed by Fynes Morison, in his 'Itinerary' (P.i., p. 208, fol., 1617), who, speaking of his bargain with the patron of the vessel which conveyed him from Venice to Constantinople, says, "he gave us good diet, serving each man with his knife, a spoon, and a fork." Ben Jonson, in 'The Divell is an Asse' (act v. sc. 4), makes Mere-Craft speak of his "pains at court" to get a patent for his "project" for "the laudable use of forks, brought into custom here as they are in Italy, to the sparing of napkins; and that they are to be "of gold and silver for the better personages, and of steel for the common sort." See also his' Volpone,' act. iv. sc. 1.

Even when Heylin published his Cosmography,' in 1652, forks for the table were still a novelty: see his third book, where, having spoken of the ivory sticks used by the Chinese, he adds, "the use of silver forks with us by some of our spruce gallants taken up of late, came from hence into Italy, and from thence into England." FORM. Everything that exists may collectively be termed the "something," in opposition to the " nothing." This " 'something" divides itself into four great divisions, namely, things, ideas, forms, and appearances. Form is the manner and mode in which a thing is presented to our conceptions. Things are of two descriptions: immaterial, as faculties and intellect; and material, as matter and bodies. The forms of the immaterial things are called categories; the forms of the material we may call figures; the form of appearances retains the name of form; and ideas are formless. The categories, according to the opinion of the writer (founded upon those of Aristotle, Kant, and many others), are the following:-1. Categories of position,-to be, not to be, and to become; 2. Categories of quality,-substance, accident, and mode; 3. Categories of relation,-cause, effect, and action and reaction; 4. Categories of quantity,-universality, multiplicity, and unity. The logical categories are possibility, actuality, and necessity. [CATEGORY.] The figures, on account of their variety, do not admit of being classified, yet we may divide them according to the senses, into shapes, colours, sounds, smells, and tastes, and into the different modes of feeling.

Form is distinguished from the real nature of things, and, considered in this point of view, the idea of form is practically used in common speech and in science. Thus we speak of a form of law, a form of government, a beautiful form, a logical form, &c. Whoever esteems the form of anything more highly than the thing itself, or through narrowmindedness confounds the one with the other, is a formalist, as many learned men and official persons are.

FORMA PAUPERIS. By stat. 11 Hen. VII. every poor person shall have original writs or subpoenas, without paying for writing or sealing the same; and the judges of all courts of record, where such suit shall be carried on, are authorised to assign clerks to write, and The agricultural or dung-fork, and a large fork for the flesh-pot, counsel and attorney to act for such person, without taking any were the only implements of this name apparently in use among our reward. It is discretionary with the court to grant this indulgence, early ancestors. The first mention of table or eating forks is probably but it is rarely refused upon petition, supported by affidavit that the found in the Chronicon Placentinum' of John de Mussis (Muratori,' petitioner is not worth 57. in the world after paying his just debts, vol. xvi., p. 584), a writer of the early part of the 15th century, who, exclusive of his wearing apparel, and the right to the matter in conwhen speaking of the luxuries of the people of Piacenza recently intro- troversy, and by a certificate by a barrister that he has good cause of duced, says, "they use cups, and spoons, and little forks of silver" action or suit. The Court of Chancery has from an early period ("et utuntur taciis, cugiariis, et forcellis argenti "). But the fork must permitted parties to sue and defend as paupers upon the same conhave been in use in some parts of Italy some centuries earlier, if ditions as the courts of law, though in that court, it seems, if the Alberti (Urbis Veneta Descriptio,' Venice, 1626, p. 221) be correct in party be in possession of the subject matter in dispute, and that should asserting that it was regarded as a mark of pride in the wife of the be worth more than 5l., he cannot except it in his affidavit, and thereDoge Domenico Silvio, who flourished towards the close of the 11th fore will not be regarded as a pauper. The privilege may be granted century, that she would not use her fingers, but employed a fork in either at the commencement of the suit, or at any period of its progress, eating (" cibum non digitis sed furcillis aureis caperet"). Coryate, in but if granted during the pendency of the suit, it has no retrospective his Crudities' (edit. 1611, p. 90), announces himself as the person effect, and the party is not relieved from the costs previously incurred. who introduced this Italian fashion into England. He says, "Here I will mention a thing that might have been spoken of before, in discourse of the first Italian town. I observed a custom in all those Italian cities and towns through the which I passed, that is not used in any other country that I saw in my travels; neither do I think that any other nation of Christendom doth use it, but only Italy. The Italian, and also most strangers that are commorant in Italy, do always at their meals use a little fork when they out their meat. For while with their knife, which they hold in one hand, they cut the meat out of the dish, they fasten their fork, which they hold in their other hand, upon the same dish, so that whatsoever he be that, sitting in the company of any others at meal, should unadvisedly touch the dish of meat with his fingers from which all at the table do cut, he will give occasion of offence unto the company, as having transgressed the laws of good manners, insomuch that for his error he shall be at the least browbeaten, if not reprehended in words. This form of feeding, I understand, is generally used in all places of Italy, their forks being, for the most part, made of iron or tel, and some of silver, but those are used only by gentlemen. The reason of this their curiosity is, because the

A person allowed to sue in form¿ pauperis pays neither for stamps, nor fees to the officers of the court, but if he obtains a verdict with damages above 5l., the officers take the fees. In case of improper or vexatious conduct on the part of the pauper, the courts will deprive him of the privilege, which is called dispaupering him; but it seems that in such cases a pauper plaintiff is never ordered to pay costs to the defendant, though, according to Blackstone, a pauper, if non-suited in his action, formerly had his election either to be whipped or pay costs. FORMEDON (a compound of the two Latin words formam doni), one of the many writs in use under the old law for commencing a real action, before the more convenient mode of trying titles to land by ejectment was established. [EJECTMENT.] It was the peculiar remedy of a tenant in tail, who claimed per formam doni, and the highest he could have, and was therefore called tenant in tail's writ of right. The writ of right was granted to such only as claimed the fee simple, for which reason the statute De Donis (Westm. 2, 13 Ed. I.) gave this writ to tenants in tail. Together with all the others used for the commencement of real actions, it was abolished by stat. 3 & 4 Will. IV. c. 27, s. 36.

167

FORMEN.

FORMEN. [METHYL, Hydride of.]
FORMIC ACID. [FORMYL.]

FORMIC ETHER. [FORMYL]

FORMULÆ, CHEMICAL. [CHEMICAL FORMULE.]
FORMYL. This name was originally applied to a hypothetical
radical (CH) supposed to be contained in formic acid, chloroform, and
other bodies, but it is now exclusively used to denote the oxygenous

radical of formic acid (CHO). This radical is unknown in a
separate condition, but in combination with oxygen and water it
constitutes-
Formic acid, CHO,HO, which originally obtained its name from
having been found present in the red ant (Formica rufa). Hence also
the name of the radical formyl. This acid may be procured from
methylic alcohol, C2H,O+HO, by the loss of two equivalents of
hydrogen, and the addition of two of oxygen. It may also be pro-
cured by mixing starch or sugar with peroxide of manganese, water,
It is formed also under a
and sulphuric acid, and distilling.
great variety of other circumstances. It unites with lead, forming a
formiate of lead, and from this, formiate of soda may be procured by
the addition of carbonate of soda. It unites freely with most of the
metallic oxides, and many of the salts when heated in closed vessels
give off carbonic acid and carbonic oxide, leaving the pure metal.
It unites also with ammonia, the salt thus formed containing the
elements of hydrocyanic acid and water.

FORTIFICATION.

168

purposes of defence with relation to the arms then newly introduced; In these the and the result of their labours was the construction of numerous strong fortresses on the frontiers of those countries. bastion system, as it is called, was invariably adopted [BASTION]; and it is remarkable that, of the very numerous projects which have been offered to the world for fortifying places, so few should have been till in the details of the plans gave rise to the denominations of the latterly of a different kind. The variations however which occurred Italian, the French, the Spanish, and the Dutch methods, in speaking beginning of the 17th centuries; but it must be observed that those of the works proposed or executed at the end of the 16th and the variations consisted chiefly in the magnitude of the angle which the was called the second flank; that is, the portion of the curtain then two faces of a bastion made with each other, and in the extent of what The first bastioned fortresses of France appear to have been very generally left between the flank of a bastion and the place where the produced face of the collateral bastion intersected the curtain. 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 characterised by small bastions, scarcely capable of receiving artillery, and placed so far asunder as to defend each other desolated the country, the attention of the French government was very imperfectly. But after the termination of the civil wars which a member of the corps of engineers then instituted, was appointed to It is the first or lowest member of the important series of FATTY ACIDS. directed to the state of the military posts; and Errard de Bar le Duc, Formyl also enters into the composition of the following compounds :fortifications. The citadel of Amiens was built according to the plan may be obtained by distilling a mix-superintend the reparation of the old, and the construction of the new Formic ether ture of formic acid and alcohol; but it is much better procured by proposed by this officer, who, in 1594, published a treatise on fortificadistilling a mixture of 10 parts of concentrated sulphuric acid, 7 of tion, in which some effort is made to determine the principles which formiate of soda, and 6 of alcohol. The distilled product should be should regulate the forms and dimensions of the works; his method, mixed with water to separate the alcohol which it contains, then however, is only a faulty modification of the Italian. agitated with magnesia to saturate any excess of acid, and lastly, freed from water by distillation with chloride of calcium. This is Döbereiner's process.

:

Its sp. gr. is 0.915 at Formic ether is a colourless liquid, of a strong odour, resembling that of peach kernels; its taste is peculiar. It mixes with alcohol in all pro65°, and it boils at 132° Fahr. portions; but water takes up only th of its weight; and after some time the solution is found to be converted into a mixture of alcohol and weak formic acid: this ether burns in the air with a blue flame, the edges and point of which are of a bright yellow. A composite acid, which stands in the same relation to the benzoic series as lactic acid does to the acetic series.

Formobenzoilic acid (C32H18012).

Formanilide, Phenyl-formiamide (C,H,NO,). One of the products of the action of heat upon oxalate of aniline. [ANILIDES.]

FORMYLIA. An organic base so-named by Clöez, but which has since been proved by Hofmann to be ethylene-diamine (N ̧CH”H.). It is formed by the action of bi-bromide of ethylene upon ammonia. FORNAX (Constellation), the Chemist's Furnace, one of the southern constellations of Lacaille. It is situated immediately below Cetus. It does not contain any stars of conspicuous brightness. FORT is the term applied to any enclosed field work, or small permanent work. It is however often very loosely applied. FORTE (Italian strong, loud), a musical term, directing the performer to sing or play loudly, with strength.

Fortissimo is the superlative of Forte.

FORTRESS, a fortified city or town, the works of which are such as to require an attack in form, or are capable of resisting an attack de vive force.

FORTIFICATION is the art of constructing works for the protection of a town or military position; the object being to enable a lesser force to be a match for a greater from the advantages of its position. Or, as in the case of offensive fortification, such as siege works, to increase the power of the assailants. Fortification has, therefore, been divided into two parts, permanent and field, the former comprising such works as are intended to last for many years, and the latter such as are hastily executed for the defence of a position of an army in the field, or the attack of a fortress.

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 ancients, 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 ancient 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

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 This direction appears to have been length of each flank, which was very short, and formed an angle of two collateral bastions; an orillon occupied nearly two-thirds of the about 80° with the curtain. 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 flanks, laying their muskets perpendicularly to the lengths of the counter-battery; but it is evident that the defenders of the opposite parapets, according to the general practice, would almost inevitably, stationed on the curtain. especially in the dark, fire upon each other, or upon those who were

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 perchanges a better defence was obtained from the flanks, and the evil pendicular direction of the latter with respect to the curtain: by these above mentioned was diminished. But a still greater amelioration was the half-front of Fortification between F and G, fig. 1, BASTION] permade by Count Pagan, who, in 1645, proposed to make each flank [see defence which the works should afford each other is thus complete, and pendicular to the produced face of the collateral bastion; the reciprocal retains the orillons at the shoulders of the bastions, and he gives to the men are not in danger of being fired on by each other. Pagan the latter double or triple flanks; but the construction of these, and of many other works supposed to be modern improvements, such as Venice in 1564: they have, however, on account of their numerous the demi-revetment, are to be found in Castriotto's work, published in inconveniences, 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, which were exercised in devising and carrying into execution, the strengthening and improving 300 places and the building of 33 new ones, together with the merit displayed in the conduct of fifty-three sieges, have given that engineer so much celebrity. the outworks were entirely remodelled; and instead of assigning for Besides the changes made in the disposition of the parts of the enceinte, 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 appli cable 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, though many of his works are found in older writers; and from that time to the present scarcely any deviations have been made from them in the construction of great fortresses. A front of fortification between G and E, fig. 1, BASTION.] brief outline of the system will therefore be here given. [See the half

The length of each side, as FE, of a regular polygon supposed to surround the town or position, is made from 320 to 400 yards, say about 380 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, but more especially that the faces of the bastions

169

FORTIFICATION.

should be within range of the flanks. This for the old smooth-bored
musket would have required a range of 180 to 200 yards, but this being
impracticable from the relief required in the bastion, and from its
further rendering the bastion too small, the length is determined by
the range of rifles, wall pieces, and grape shot, which is about 300 yards.
Now these being supposed to be placed on the flanks, as at e orf,
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 covered-way (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 F 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 2-7ths of EF, in order
that, in the inferior polygons, the bastion may have sufficient capacity,
we obtain about 380 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 one-sixth 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 perpendicular 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 f 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 necessity of obtaining from it the earth for the formation of the ramparts and parapets, the depth being fixed by giving the escarp the least height which is considered quite secure from escalade. This for the main works should be about 32 feet, which gives a breadth of ditch at the flanked angles of the bastion of 38 yards. The counterscarp wall is rounded opposite the flanked angles at E or F, and is directed from thence towards the shoulder of the collateral bastion.

The improvements made by Vauban in the ravelin are described under RAVELIN: Q represents one-half of that work; and it will be merely necessary here to say, 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 fire of the besiegers, which Vauban was the first to employ in the attack, in which he was even more famous than in the defence, being the first to give it that decided superiority which it has ever since maintained, and one of the principal He was the first engineer who means of which was the ricochet fire. formed the spacious places of arms, as they are called, at L, in the reentering 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 3 or 4 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 coveredway. 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 tenuille, 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.

His

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 fortified Neu Brisach, some few modifications which he was led to the denomination of his second system; and when, subsequently, he 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 This great engineer died in 1707, at the age of 74 years; and, from formed casemates to contain artillery for the defence of its ditch. his time, the French fortification has been to a great extent that of all It would be improper in this place to omit the name of Minno, Europe. Baron of Coehorn, who was born in the year 1641, the year preceding the birth of Vauban, and who in the service of the United Provinces acquired a reputation scarcely inferior to that of his great rival. In the year 1692 they were directly opposed to one another, Coehorn defending Namur against Vauban, who conducted the attack. system, or systems, as he in his treatise describes three, are essentially adapted to aquatic sites, such as those of Holland, and he applied them, with the modifications required by the ground, to Nimeguen, Breda, Manheim, Namur, and Bergen-op-Zoom. Tilbury Fort is also on his system. The outline of the plan differs but little from that of his rival's great system, but the shoulders of the bastions are strengthened by large towers, or orillons, containing casemates. In the interior of each bastion is another, on a higher level, and on the exterior is a counterguard, consisting of two faces, parallel to those of the bastion. A large ravelin, inclosing a redoubt on a higher level, is placed before the curtain, and the whole is surrounded by a broad covered-way, whose places of arms are retrenched by brick redoubts. The plane of which allows the system to combine the advantages of wet and dry site of the works is assumed to be 4 feet above the level of the water, ment is saved, and the dry ditches which separate the unrevetted ditches. When the wet ditches are employed the expense of the revetportions from the principal works afford the garrison a great advantage in resisting the besieger while defiling from his bridge across the wet ditch to attack the inner works, which have a sufficient revetment to resist an assault without ladders, but are still low enough to be proravelins as of the covered-way, are sunk below the natural surface of tected from distant fire. The terrepleins, as well of the bastions and the fortifications are supposed to be constructed, for an enemy to dig the ground, so that it would be impossible, in the marshy soil on which 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.

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 the glacis before the former works will also connect that which is centre of the place, the trench executed by the besiegers to connect before the latter; and that, in consequence of this construction, and outworks. With the view, therefore, of preserving the former breaches may be formed, and assaults made, at one time, in the enceinte 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. faces on the faces of the collateral bastions, at 22 yards from the Thus the magistral line of his ravelin is determined by directing its shoulders; and its salient or flanked angle by the intersection of the perpendicular produced of an arc described from one of these points as a centre, and the shoulder of the opposite bastion as a radius. By the glacis of a bastion till he had got possession of the two collateral this construction it would become impossible for an enemy to crown his approaches between them; and the fall of the place would be ravelins, on account of the fire which, from these, might be made upon delayed by the time spent in conducting the approaches from the ravelins to the intermediate bastions.

In order that this benefit might be obtained in the highest degree, Cormontaingne suggested the propriety of fortifying places on polygons more fronts of fortification on one straight line; this practice would of the superior kind, and even, when possible, of constructing two or bastions very obtuse, by which, not only would the increased capacity have the additional advantage of rendering the flanked angles of the 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 completely secured from the enfilading fires of the besiegers.

Besides the above general modifications, Cormontaingne made several

Plan of a Front of Fortification according to the Method of Cormontaingne.

A. Solid Bastion; B, Hollow ditto; x, Retrenchment; P, Tenaille; o, Caponnière; a a, Ravelin; y, Redoubt in ditto; L L, Re-entering places of Arms; w w, Redoubts in ditto; R R, Covered-way; t t, Traverses; s s, Glacis; z, Barbette battery.