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Alloa, it winds in a most beautiful and pictu- dance of fish. Whales have frequented it during resque manner : so that, though it is but four several centuries : the porpoise is common. miles by land, it is twenty-four by water between Stirling salmon are exceedingly plentiful; cod those two places. Below Alloa the river ex- and haddocks are taken in great quantities; and pands itself to a great breadth between the coun- it is frequented by myriads of herrings. At ties of Lothian and Fife, till at Queensferry times these are so plentiful that they are sold at it is contracted by promontories shooting into the cheap rate of sixpence a hundred. Crabs it from both coasts; so that, from being four are caught in many places ; lobsters are not rare, to five miles broad, it becomes not above two but bear a much higher price; and oysters and miles. Here in the middle of the channel lies muscles are in great profusion. Valuable minea small island called Inchgarvy, and, a little rals are obtained from almost every part of the below that, those of Inchcolm and Inch-keith. environing shores. The beds of coal are inexThe north and south shores receding, below haustible, apparently lying under the whole bed Queensferry, the body of the water gradually en- of the river between Čulross and Borrowstownlarges till it becomes two or three leagues broad, ness. Lime is wrought on both sides, but chiefly affording several safe harbours on both sides, and at Charleston, in the county of Fife, about thirexcellent roads throughout, unembarrassed with teen miles north-west of Edinburgh. Along the latent rocks, shoals, or sands; and allowing se coast numerous petrifactions occur. Ironstone cure anchorage to the largest ships within a league is plentifully obtained from pits, or collected in of the coast in almost any part of the Frith, and scattered nodules ; and small portions of fine to vessels of a smaller size within a mile or less. jasper are frequently seen. The Forth contains The Forth was known to the ancients by the several islands, of which the chief are Inchgarvie, name of Bodotria, or, as Ptolemy calls it, Bode- Inchcolm, Inchkeith, the Bass, and the isle of ria, and has been ever famous for the number of May. Light-houses are erected on Inchkeith its havens. It is navigable for merchantmen as and on the Isle of May; and the ruins of castles high as Alloa, fifty miles from the sea ; and, for or religious houses appear on all the islands. coasters, as far as Stirling, twenty-four miles The towns connected with the river, though they, further by water, though only four by land in a' in general, drive a brisk trade, are principally direct line, as already observed. The tide flows small; for, excepting Stirling, Alloa, and Leith, only a full mile above Stirling. The direct few of them contain 3000 inhabitants. Batteries course of this river is scarcely less than 100 miles, have been erected on different parts of the banks, and its sinuosities do not occupy a shorter space as also on the island of Inchcolm, than 200. Its depth is from three to thirty-seven pose of protecting the channel. fathoms, or more; the bottom, in many or per- 1774 it was proposed to render the Forth navihaps most places, covered with sleach, especially gable from Stirling bridge to Gartmore, and to above the ferries. The principal tributary rivers cut a canal in a straight line from Stirling to of the Forth are the Goodie, Teith, and Allan, Alloa, whereby the navigation would be shortened above Stirling bridge; and, below it, the Devon, from twenty-four miles to six. At a later period, Carron, Avon, Almond, Leith, Esk, Leven, Tyne, namely, in 1806, a project was entertained of and others: these chiefly flow into the river on excavating a tunnel under the bed of the river, the south shore. A navigable canal, com- to obviate the interruption which passengers mencing near Grangemouth, communicates with experience at the two ferries, and elsewhere, from the Clyde.
occasional storms; but, after an elaborate survey, In the Forth are found great variety and abun- the plan was abandoned.
the purIn the year
FORTIFICATION. The origin of fortification exercise : they afforded sufficient space for the was doubtless that principle of rapacity, which defenders to use them as stations for attack, and has infuenced too many of mankind in all ages they were crowned by other and smaller works, and nations to invade the rights and properties through which they discharged missiles. Long of those whom they considered weak or defence- before Rome was founded, the ancient Grecians less. In the first ages of the world men were used brick, and rubble stone, with which they dispersed over the earth in separate families, as built a vast wall, joining Mount Hymettus to the appears in the records of the Jews and Scythi- city of Athens. The Babylonian walls, built by ans, and they wandered from place to place in Semiramis, or, as others state, by Belus, were search of pasture for their cattle. But families thirty-two feet thick, and 100 feet high, with soon became numerous, and formed large com- towers ten feet higher built upon them, cemented munities which settled in one place; even with bitumen or asphaltus. Those of Jerusalem before the deluge - the earth was filled with vio- seem to have come but little short of them, since, lence,' and towns and cities arose. It was now in the siege by Titus, all the Roman batteringfound necessary, for the common security, to rams, joined with Roman art and courage, could surround these towns with walls, and the first, remove but four stones out of the tower of of course, were of the simplest construction; Antonia in the assault of a whole night. they were single, and perhaps perforated. Then The square towers at first used would suffi. they were built of more solid materials; the ciently protect every part of the wall, adjacen best arts of masonry were here called into to the sides of these towers. But, as there al.
ways remained one of the faces of the towers tance from each other, as are those still to be seen which fronted the field that could not be seen at Antwerp, their gorges narrow, and their flanks from any other part, the circular form was early and faces short. For the invariable practice preferred. This had also the recommendation then, and for some time after the introduction of presenting a better resistance to battering of them, was to attack the curtains and not the engines. Still there remained parts of these faces of the bastions. But since that time they towers unseen and incapable of being defended; have been considerably improved and enlarged, which caused a second change in their figure, and are now arrived to that degree of strength, i. e. they made them square as before; but, that it has been a received opinion, that the art instead of presenting a face to the field as for- of fortification is at its height, and incapable of merly, they presented an angle, the origin of our being carried to greater perfection. This, howmodern bastion ; and thus was effected such a ever, Mr. Glenie, p. 9, Military Construction, disposition of the works, that no part could be disputes, and M. Carnot seemed resolved, a few attacked without being seen or defended from years since, to confirm his opinions as to all some other part. Ditches were added; and past methods. thus remained long stationary the art of fortif Offensive fortification is a term improperly cation : indeed until the invention of that terri- applied to the besieging and taking fortified ble assailant gunpowder. This entirely changed places; it is said further to teach a general how the mode of attack, and by consequence that of to take all advantages for his troops ; the manner defence.
of encamping, and method of carrying on either In the history of fortification we find this a regular or irregular siege, according as circumobvious division, and we need not take back the stances may direct. It may with much greater modern reader beyond the period of this cele- propriety be called the war of sieges. See brated invention.
SIEGES. When the besiegers began regularly to use Fortification has been sometimes treated of artillery, it became requisite that the besieged under the terms regular and irregular. should also employ it; and, to furnish room for Regular fortification is that which is erected this, a rampart was first raised behind and close according to the rules of art, and is particularly to the main wall of fortresses: the towers were applied to a construction made from a figure or enlarged; and the smaller walls were thickened polygon, which has all its sides and angles equal. by parapets of earth behind, so as to secure the The Hanked or salient angles in such a fortificabesieged from the fire of the enemy.
tion are equal to one another, equally distant For a length of time fortified towns were from one another, and are each of them at the placed, by these means, in a situation to take distance of about that of serious musket shot their full advantage of the new art of war. from the flanks which defend it. For an irreSieges were by no means diminished in their gular fortification having the flanked angles, as ordinary length: a wall of Magdebourg is re- also the flanks and lines of defence, unequal, corded to have received 1550 cannon-shot, in the may be constructed from the sides of a regular early part of the seventeenth century, without polygon, as well as from those of an irregular injury to it. If the siege of an important place polygon, by drawing the perpendiculars to the was not early successful, it generally terminated regular polygon from points different from those in the loss of the major part of those who as- of their bisections. See Glenie's General Rule saulted it.
for Irregular Construction. But the great modern proficient in this art, M.
Irregular fortification, on the contrary, is Vauban, now appeared, and effected at the end of that where the sides and angles are not uniform, the seventeenth century a complete revolution in equi-distant, or equal; which is owing to the it. He invented a method of attack, against which irregularity of the ground, valleys, rivers, bills, no mode of defence hitherto adopted has been &c. able finally to stand; and though, during the Most fortifications are a mixture of regular latter part of his life, he applied his great talents and irregular works. The position of waters, also to a system of defence, upon which hills, and other principal geographical features Coehorn, Cormontaingne, and others as of a site of ground, previous plans adopted, shall see have improved, nothing has as yet fully and various other considerations induce the counteracted the mode of ricochet firing intro- ablest engineer to be content with arriving only duced by this celebrated commander at the at the utmost practical regularity. In this arsiege of Ath. We shall not fail, in the sketch ticle, therefore, we shall pursue the main divisions of this art that follows, to include every princi- .of permanent and field fortification, as embrapal suggestion that has been made on this sub- cing all the principal topics we need discuss; ject, and, among others, the plan of M. Carnot, and shall present under each a brief sketch of the so justly celebrated for his mathematical skill and
most approved systems from that of M. Vauban military talents. But we have completely satis- downwards. We shall subjoin a few observafied ourselves that the vertical fire on which he tions on the mode of attacking fortified places. mainly relies is a chimera. Modern fortification treats of the plan.of de
PART I. fence now used, i.e. turning the walls into ram OF PERMANENT FORTIFICATIONS. parts, and square and round towers into bastions,
Sect. I.-M. VAUBAN'S FIRST SYSTEM. defended by numerous outworks; all which are made so solid that they cannot be beaten down, M. Vauban was clearly indebted to his predecesbut by the continual fire of batteries. These sor in this art, the count de Pagan, for his general bastions at first were small, and at a great dis- definitions and dispositions, especially in his first
system. The former has the same divisions of arcs, their parts ab, bc, &c., together with these the art into little, mean, and great fortifications, arcs, will represent the outline of the ditch. &c. But his line of defence was too long to It will be now necessary to attend to the folallow the musquetry fire of the flanks to bear lowing, Definition of Terms:-1. The part, properly, and his ravelins were tuo small. The FEALN, is called the bastion. 2. A E, A L, farge size of his orillons was also objectionable, the faces of the bastion. 3. E F, LN, the flanks. and the faces of his cavaliers were not flanked. 4. FG, the curtain. 5. F N, the gorge of the Vauban also materially improved his covert bastion. 6. AG, B F, the lines of defence. 7. way. His first system adopted, as we said, Pagan's A B, the exterior side of the polygon. 8. CD, divisions of little, mean, and great fortification; the perpendicular. 9. Any line, which divides a by the first he intended the construction of ci- work into two equal parts, is called the capital tadels; by mean fortification, that of all sorts of of that work. 10. abc, the counterscarp of the towns; and by great, that of particular and im- ditch. 11. A, M, the flanked angles. 12. H, portant places. We shall give the construction E, L, the angles of the shoulder, or the shoulder of the mean as being most useful; and refer only. 13. G, F, N, the angles of the flank. 14. to the table hereafter inserted for those dimen- Any angle whose point turns from the place is sions which are different in other fortifications. called a saliunt angle, such as AM: and any
Inscribe in a circle a polygon of as many angle whose point turns towards the place, resides as the fortification is designed to have entering angle, such as b, F, N. 15. If two fronts ; let A B, fig. 1, FORTIFICATION, plate I. be lines be drawn parallel to the principal or outone of the sides of half an hexagon, which bi- line, the one at three toises distance, and the sect by the perpendicular C D; divide half of other at eight from it; then the space yr init AC into nine equal parts, and one of these cluded between the principal one and that farthest into ten others; then these divisions will serve distant, is called the rampart. And the space as a scale to construct all parts of the fortifica- rf, contained by the principal line, and that tion, and each of them
is supposed to be a toise near to it, and which is generally stained black, or fathom, that is six French feet; and, there- is called the parapet. 16. There is a fine line fore, the whole side A B is supposed to be 180 drawn within four feet of the parapet, which extoises. As the dividing a line into so many equal presses a step called banquette. parts is very troublesome, it is much easier to N. B. All works have a parapet of three have a scale of equal parts by which the works toises thick, and a rampart of eight to ten, bemay be constructed.
sides their slopes. If, therefore, in this case, the rauius is taken 17. The rampart is elevated more or less above equal to 180 toises, and the circle described with the level of the place, from ten to twenty feet, that radius be divided into six equal parts, or according to the nature of the ground and the the radius be carried six times round, we shall particular constructions of engineers. have an hexagon inscribed; A B being bisected 18. The parapet is a part of the rampart eleby the perpendicular C D as before, set off thirty vated from six to seven feet and a half above toises from C to D, and draw the indefinite the rest, in order to cover the troops which are lines A DG,BDF; in which take the parts A E, drawn up there from the fire of the enemy in a BH, each equal to fifty toises; from the centre siege; and the banquette is two or three feet E describe an are through the point H, meeting higher than the rampart, or about four feet lower A D in G, and from the centre H describe an than the parapet ; so that when the troops stand arc through the point E, meeting B D in F; or, upon it, they may just be able to fire over the which is the same, make each of the lines EG, parapet. H F, equal to the distance E H; then the lines 19. The body of the place, is all that which is joining the points A, B, F, G, H, B, will be the contained within the first rampart; for which principal or outline of the front.
reason it is often said to construct the body of If the same construction be performed on the the place; which means, properly, the construcother sides of the polygon, we shall have the prin- tion of the bastions and curtains. cipal or outline of the whole fortification. If, 20. All the works which are constructed bewith a radius of twenty toises, there be de. yond the ditch before the body of the place are scribed circular arcs, from the angular points, called outworks. B, A, M, T, and lines drawn from the oppo M. Vauban gives the following Table of Disite angles, E, H, &c., so as to touch these mensions:
Sides of polygons . 80 90 100 110 120 130 140 150 160 170 180 190 200 260 Perpendiculars 10 11 15 16 20 21 | 23 25 30 31
0 160 170
110 120 13
Faces of bastions
22 25 28 30