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A47731 The new method of fortification, as practised by Monsieur de Vauban, Engineer General of France with an explication of all terms appertaining to that art / made English. Vauban, Sébastien Le Prestre de, 1633-1707.; Swall, Abel. 1691 (1691) Wing L1116; ESTC R15758 87,678 223

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Feet into 10 others so one of these last 10 will make the hundredth part of your Line that is to say one Fathom of your Scale 2. To make the Scale well you must divide also one Fathom into six other equal parts to shew the Feet for a Fathom is six Geometrical Feet as have been already said And by this manner you will have a perfect Scale for to know all the Breadths Lengths and Heights 3. When you would make any thing tha● should be very exact you must likewise take a Foot and divide it into 12 other equal parts and so you will have the Inches for a Foot contains 12 Inches CHAP. II. How to make the Design of a Square IN France there are three sorts of Fortifications the Large the Middle-siz'd and the Small but at present they never make use but of the Middle-siz'd Nevertheless we will first shew the Difference before we speak of the Middle-siz'd The Square The Large Manner   Fathoms Feet 1. The Semi-diameter 141 00 2. The Side or Exterior Polygon 200 00 3. The Perpendicular 27 00 4. The Face 60 00 5. For the Complement of the Line of Defence take 38 00 6. The Flank 22 00 7. The Curtin 73 04 8. The Line of Defence 141 04 The Middle-siz'd   Fathoms Feet 1. The Semi-diameter 127 02 2. The Exterior Side 180 00 3. The Perpendicl●ar 22 00 4. The Face 55 00 5. For the Complement of the Line of Defence take 33 00 6. The Flank 18 01 7. The Curtin 64 04 8. The Line of Defence 1●6 00 The Small   Fathoms Feet 1. The Semi-diameter 113 01 2. The Exterior Side 160 00 3. The Perpendicular 21 00 4. The Face 45 00 5. For the Complement of the Line of Defence take 33 00 6. The Flank 18 04 7. The Curtin 64 00 8. The Line of Defence 115 04 The Explanation of the Middle-si●'d Table HAving seen the Difference between these three Manners we shall only speak of the Middle-siz'd as being the most in use at this Day and to begin we will examine the said Middle-siz'd Table 1. Take 127 Fathoms and two Foot between the Points of the Compass and make a Circle 2. Take 180 Fathoms and divide them with the Circle into four equal parts When they are joyned the one to the other they are called Exterior Sides or Polygons as A B C D. 3. Divide one of these four Sides into two equal parts with 90 Fathoms as E F G H. 4. Draw from the Points E F G H. streight Lines toward the Center which are called Perpendiculars to which must be allowed 22 Fathoms in length as I L M N. 5. Set the Rule to the Capital Points A B C D. and draw streight Lines through the end of the Perpendiculars I L M N. at pleasure 6. Take 55 Fathoms and place them upon the Lines drawn from the Capital Points to mark out the length of the Faces as a b c d e f g h. 7. Take 35 Fathoms and put them from the Point where the Perpendicular ends viz. from the Point I L M N. upon the Lines tha● have gone beyond the said Points to mark out the length that is to be taken for the Complement of the Line of Defence as JO. JP. LQLR MS. MT NV. NX 8. Draw the end of the Faces and these Points OPQRSTVX which terminate the Complement of the Defence and you will have the Flanks 9. Then joyn together the Feet of the Flanks and you will have the Curtins To make the Orillon MOnsieur de Vauban does not leave his Flanks as Monsieur Pagan has done or as the Dutch and Germans do at this Day but he conceals one part the better to cover the Cannon by means of the Orillon And for that Reason we will shew you his manner of raising it which is not very difficult 1. Divide the Flank into three equal parts 2. Divide the first of the three into two other equal parts to joyn from this Middle the two Extremities of the first part on the side of the Moat and this little Rounding makes the Orillon To make the Hollow Tower or Flank retir'd AS you have seen the Reforming of the first of the three parts placed upon the Flank now you shall see another of the two remaining parts the Form of which you must henceforward call the Hollow Tower the Constructure of which is thus 1. Draw from the Capital Points of the Bastions a small streight Line within side of the Bastion through the end of the Orillon 2. Put five Fathoms upon this Line which you have drawn as also upon that which is almost parallel to the lower part of the Curtin This is called the Brisure 3. Take the Extremities of the Brisure with the Compass and with that Distance draw two Arches which intersect one another toward the Moat in Figure 8. 4. Put the Compass upon that Intersection and joyn the said Extremities of the Brisure together by a crooked Line and thus you will have the Figure which is made at this Day in France in stead of the Flanks as also the Design of the Entire Square See under B. Fig. 3. CHAP. III. Of the Structure of the Body of the Place of the Square WE are now to see what Largeness or Breadth is to be allowed to the Ramparts Parapets Moats Covert Ways and Glacis's of Squares and after what manner they are to be drawn Observe then what follows   Fathoms Feet 1. The Base of the Rampart 11 00 2. The Base of the Parapet 03 00 3 The first Banquet 00 1 ⅓ 4. The second Banquet 00 02 5. The Moat from 16 to 20 00 6. The Covert Way 04 00 7. The place of Arms 13 00 8. The Glacis 36 00 In case the Ground will give you leave to take more you may do it The Explanation of this Table 1. Take 11 Fathoms and carry them parallel to the Curtins Flanks Faces Brisures and Hollow Towers on that side toward the inside of the place to know after what manner you are to draw the Parallel to the Hollow Tower Put these 11 Fathoms before then open your Compasses to the Point from whence you drew your Hollow Tower and draw from the same Point through the said 11 Fathoms a crooked Line till it joyns the Basis of the Brisure and the Face 2. Take three Fathoms and carry them in the same manner parallel to the Design to the end the Basis of the Rampart may be opposite to it and parallel But you ought to make this Parapet or three Fathoms parallel also to the Orillon as far as the Brisure For there it is that the Parapet of the Orillon ought to end As for the Hollow Towers put as already has been said three Fathoms for that is the breadth of the Parape● before the Hollow Tower and open the Compass to the point from which you drew the Hollow Tower and the Base of its Rampart to draw from the same point
point G which touches the given Line only in K. 2. With the distance GK draw another Arch upon the given Line MN 3. The Line drawn by GN shall be parallel to the given Line HI III. To raise Perpendicular on a given Line from a given point 1. Take a distance from the given point what you please to the right as AB 2. Take the same distance to the lest as AC 3. Take BC and draw two Arches which intersect each other at D. 4. Joyn D and A together and you will have your Perpendicular IV. To raise a Perpendicular at the end of a given Line AB 1. Draw a Circle to the point B from the center C which may be taken at pleasure 2. From the point D where the Circle cuts the given Line draw a right Line through the Center C till it touches the Circle on the other side as at E. 3. Joyn E and B together and you will have your Perpendicular V. From a given point G to let fall a Perpendicular upon a given Line 1. Draw an Arch from the point G which may cut the given Line in two places as CD 2. From CD draw two Arches under the Line which shal● intersect each other at E. 3. Joyn E and G together and you will have your Perpendicular GF VI. To divide a given Line into two equal parts 1. From the points AB draw two Arches which shall intersect above the given Line at C and below it at D. 2. Joyn C and D together and you shall have your Line cut into two equal parts VII To divide a Line AB into several equal parts 1. Draw CD a Line at pleasure and mark as many parts as the given Line AB ought to have six for Example upon this Line as CE. 2. Take CE and draw two Arches which may intersect in F. 3. Draw all these six parts in F. 4. Take the given Line AB and lay it upon the Lines FE and FC as GH 5. Joyn GH together you will have your given Line AB divided into six equal parts VIII To describe an Angle equal to an Angle given 1. Let the given Angle be BAC 2. Draw the Arch ADE 3. Draw a Line IL and upon this Line an Arch with the distance AD as FG. 4. Set the distance DE upon the Arch FG as FH 5. Draw a right Line from the point I to the point H which will make an Angle equal to the given Angle IX To divide an Angle into two equal parts 1. Let the given Angle be BAC draw the Arch ADE 2. From the points DE draw two Arches which shall intersect each other at F. 3. The Line drawn from F to A will cut the Angle into two equal parts X. To draw a Circle through three given points ABC or to find the Center of a given Circle or to finish a Circle when there is but one part given 1. With the points AB make two Arches which shall intersect at D above and at E below the given points 2. Draw a right Line from the point D to G. 3. Do the same thing with BC so that they may intersect in FG. 4. Draw another right Line from F to G and there where this Line intersects the first as for instance at G you will find the Center by which you may draw the Circle through the three given points XI To make a Circle two three or four times bigger than the given ●ne c. 1. Divide the given Circle into four equal parts ABCD with the Center mark'd at E. 2. Take the distance AB and put it from E upon the Perpendicular as EF and with this distance draw a Circle as big again as that given 3. To make a Circle twice as big take AF and put it from E upon the first Perpendicular as EG and the distance EG will be the Semi-diameter of the demanded Circle 4. To make a Circle thrice as big put the distance AG upon the same Perpendicular as EH and the distance EH will be the Semi-diameter of the demanded Circle Thus you may enlarge a Circle for ever XII To make an Oval 1. Draw a Line and thereupon the Circle BAC 2. From C draw another Circle through B as CBD 3. Take care that these two Circles intersect each other as in EF. 4. From the point of intersection E draw right lines through BC which shall touch the two Circles in GH 5. From the point E draw an Arch from G to the point H. 6. Keep this distance and do the same thing from the other point of intersection F as IK and so your Oval will be compleat XIII To draw a Spiral Line 1. Upon a straight Line draw the Arch ABC 2. Take BC and fixing one point of the Compass upon B draw from the point C another Arch which shall touch the same Line in D. 3. Take the first Center A and draw another Arch from D that shall touch the line in E. 4. Return to the point B and from it as a Center draw from E another Arch to F. 5. Take A as a Center and draw an Arch from F to G and so on for ever XIV To divide a Circle into 360 equal parts 1. Divide a Circle into four equal parts as ABCD whose Center is E. 2. From A thro' E draw the Arch FG so also draw from B the Arch IH and from C draw and the third KL and at last from D draw the last Arch MN 3. Having by these Arches divided the Circle into twelve equal parts afterwards divide every one of these twelve into three other equal parts and then you will have thirty six equal parts 4. Divide afterwards every one of these thirty six into ten equal parts and your Circle will be divided into three hundred and sixty equal parts XV● To make an Equilateral Triangle Take a given line AB and from those two points draw two Arches which shall intersect at C from C draw two right lines to A and B these will make an Equilateral Triangle XVI To make a Triangle equal to a given One 1. Let the given Triangle be ABC draw a line at pleasure and mark thereupon the length AB as DE. 2. Take the distance BC and from the point E draw an Arch. 3. Take the distance AC and from D draw another Arch which shall intersect the first at F. 4. Joyn FE and FD together you will have a Triangle equal to the given one ABC XVII To divide a Triangle into several equal parts 1. Let ABC be the Triangle to be divided into five other Triangles first divide the longest side BC into five equal parts so that the fifth part marked at D may be joyned to A. 2. Divide the longest of the two other sides into four equal parts and let one of them marked G be joyned to D. 3. Divide the remaining part DC into three equal parts and joyn that marked F by a right Line to G. 4. Divide the
streight Line as also FR and FE 5. Divide the Lines EF into two equal parts from the middle of which set down a Perpendicular of 20 Fathoms GH 6. Draw the Faces ●s for the body of the place their length is 38 fathoms 7. For the Complement of the Line of Defence take 21 fathoms 2 feet which joyn together after the end of the Face and of the Complement to have the Flanks Draw the Curtin also 8. To make the Orillon and the Hollow Tower go the same way as is set down in Lib. 3. Chap. 2. only that you do not divide the Flank but into two equal parts Monsieur de Clermont would have allowed to the Orillon of the Square two fifth parts of the Flank 9. The Base of the Rampart is to contain 8 fathoms that of the Parapet 3 that of the Moat 12 that of the Covert-way 5 the first and second Banquet are to have the same wideness as has been mentioned above The TABLE   Fathoms Feet● The Capital QG 88 00 The Wing DE 118 00 The Perpendicular GH 20 00 The Face EL 38 00 The Flank LN 15 0● The Complement c. HN HM 21 03 The Curtin MN 38 05 The Line of Defence EM 84 04 The Base of the Rampart 08 00 The Base of the Parapet 03 00 The first Banquet 00 01 1 ● The second Banquet 00 02 The wideness of the Moat 12 00 To make a Ravelin before these Horns 1. FRom the Angle of the Moat of the Horns erect a streight Line of 24 fathom for the Capital OP 2. From the point B draw right Lines toward the Orillon of the two Bastions of the Horns terminating at the Moat as OQ OQ 3. Draw the Base of the Rampart and the other distances as in the working of the Horn-work only that the Moat ought not to be wider than 8 fathoms nevertheless it must have its Rounding 4. The Covert-way the places of Arms and Glacis are made as in the body of the place See the Plate C c. 4. l. 3. CHAP. VII To make a Horn-work before the Bastion 1. FRom the point of the Bastion draw a streight Line of 86 fathoms AB 2. From the point B draw to each side an Arch of 60 fath 3. Take from 118 to 120 fathoms and resect those two Arches in CD the Angles where the Moat of the Ravelin throws it self into the Moat of the body of the place as EF. 4. Joyn EC CD and DF together by streight Lines 5. Divide the Line CD into two equal parts from the middle of which draw down a Perpendicular from 18 to 20 fathoms as BH 6. Draw the Faces as usually their length is to be 38 fathoms as KI the Complement is 21 fathoms 2 feet as LN lastly all the rest is done as in the Horn-work before the Curtin the parts of which have the same distan●● See the Plate E Fig. VIII CHAP. VIII To make a Horn-work with Shoulders 1. PRolong the Flanks towards the Field to the length of the Curtin AB CD 2. From B and D draw a Perpendicular of from 25 to 28 Fathoms as BE DF. 3. From the Points EF raise other Perpendiculars from 118 to 120 Fathoms as EG HF. 4. Joyn GH together by a streight Line which you shall divide into two equal parts and from the middle of which you must bring down a Perpendicular of 20 Fathoms as IK 5. Draw the Faces as usually the length of which must be 35 Fathoms 6. The Complement of the Line of Defence is found by putting the Compass upon the Extremity of the two Faces and then keeping one Point of the Compass standing in its place let the other fall upon the Line of Defence Which is also to be done on the other side as LM NO 7. LM and NO are drawn together for the Flanks as also MO for the Curtin 8. To have the Orillion take two fifth parts of the Flank of this Work the rest is made as usually in like manner as the hollow Tower or Flank retired 9. The Base of the Rampart c. ought to have the same wideness as the rest of the Horn-works and to be drawn parallel as far as the Moat of the Body of the place 10. The Ravelin before this Work is made as already has been set down in Chap. 6. Lib. 3. See the Plate F Fig. IX CHAP. IX To make a Horn-work with a Crown 1. DIvide the Exterior Polygon of the Hown-work into four equal parts AB CD 2. Take three parts of these four and describe them with an Arch at the Angle of the Moat of the said Work E. 3. From the point H erect a Perpendicular as far as the Arch F. 4. Put the same three parts of the point F upon that Arch● as FG and FH and joyn FG and FH together by a Right Line 5. From the Line FG and FH bring down a Perpendicular of 16 Fathoms as IK LM then draw the Faces as usually of which let the length be 29 Fathoms 6. For the Complement of the Line of Defence take 15 Fathoms and then draw the Flanks and the Curtin as above 7. Prolong the Faces of the Horns to 27 Fathoms as AN DO and joyn GN and HO together by a Right Line 8. Put 24 Fathoms upon the Wing of the Horn on the side of the Place at the points AD as AP and DQ 9. From the Points N and O draw streight Lines towards the Points PQ which terminate on the side of the Moat of the Hornwork in RS. 10. To make the Orillion divide the Flank into two equal parts of which the one serves for the said Orillion and the other for the Flank retired You are to observe that the Flanks which joyn their Faces to the Moat of the Hownwork are left without an Orillion ● and a retired Flank as NR OS 11. The Base of the Rampart c. and all the other distances are formed as in the Horn-work See the Plate F Fig. X. CHAP. X. To make a Crown-work before the Curtin 1. FRom the Capital Point of your Ravelin erect a Perpendicular of 100 Fathoms and if there be no Ravelin take the Cur●in● of the body of the place with the Brisur● to draw two Arches which cut one the other before the Curtin From which Point of the Intersection you must do as I have already said concerning the Capital Point of the Ravelin as AB 2. Take the same 100 Fathoms and make an Arch from the point B to each side 3. Take 113 Fathoms and resect those two Arches as the beginning of the Orillon CD and EF. 4. Joyn EB and BF together by right Lines and draw streight Lines from the points EF towards the Orillion of the place terminating upon the side of the Moat GH 5. Divide the Line EB and the other BF into two equal parts from the middle of which bring down Perpendiculars each from 15 to 16 Fathoms as IM LN 6. You are to
the Place of an equal bigness to the Line DE that is to say of five Fathoms as KI to the end that you may have the Brisure where you may place the piece of Cannon that points towards the Half Moon cannot be batter'd from the Field because it is as it were covered by the Ravelin Lastly To make the Rounding of the Flank retir'd take the Distance KE between the Points of the Compass and make Sections toward the Moat in L from whence afterwards draw the Arch from K to F. It cannot be said but that these Orillons are very good for these Roundings give less advantage to the Enemies Cannon and enlarge the room as well for placing the Cannon as for the Musketeers If you object That the Distance from that part where the Enemy may pass the Moat is too great I answer That the principal Defence of the Small Shot to hinder the Passage of the Moat consists in the Ten●ille where you may set a Body of Musketeers to fire continually Upon this Method Monsieur de Clermont observes That the Orillon of the Square would be too little if you allow it no more than the Third Part of the Flank as to the Polygons and therefore he requires Two Fifth Parts of the same Flank for the Orillon See the Plate P. Fig. XXII at the end of the Third Book CHAP. V. Of the Curtain IN regard that the Curtain ought to cover the greatest part of a Work it is requisite that it should be of a reasonable Length that is to say that it should never be shorter than Sixty Fathoms and never longer than an Hundred M●rsh●user allows it 72 Fathoms and Freittag as much Goldman would have the Length to be of 96 Fathoms Anthony de Ville 100. Tieu makes it 74 Fathoms in Length Himsel 84. Monsieur de Clermont allows it Three Fifth Parts of a Polygon The Count de Pagan 60 Fathoms Monsieur de Vauban forms it according to the Plurality of the Bastions As you may see Lib. 3 c. 17. As to the Figure of the Curtains there are some Engineers who will have them ●o be as is mark'd at the Letter A of which the Construction is such See the Plate P. Fig. XXII at the end of the third Book 1. Divide the Line AB into ● equal parts as AD DM NC and CB and take ● for the Demi-Gorge as BC AD. 2. Divide the same Line AB into three equal parts and take one for the Capital as BE A● 3. Where these three Parts are marked as at R and G bring down from the Points R G two Perpendiculars of which se● each have the third part of the Capital Line for its length as RH and GI and then joyn H and I together by a Right Line 4. Make upon the Points D and C the Angle of the Curtain of 100 degrees and allow to the ●lank the length of the Demi-Gorge ●● DP and CQ This being done joyn EQ and DP together to have the Faces The defects of the Curtain are 1. That it is too short 2. That the ●ortification takes up too much room 3. That it renders the Bastion too Acute Others there are that form an Angle without side as that which is marked with the Letter B. The Construction of which is after this manner 1. Divide the Line AB into five equal parts as AC CD DE EF and FB 2. Divide the first Line AB into three equal parts and allow one for the Capital as AI and BK then join HI and BK together to gain the Faces 3. Divide the Curtain CF into two equal parts and up●n the middle marked with the Letter L erect a Perpendicular which has the half of the Face GK as LM 4. Draw from CF two streight Lines to the Point M and your Curtain will be made See the Plate P. Fig. XXIV ●●hers make the Curtain of a C●rcular Figure within●s●de like that which is marked C The Construction of which is as follows See the same Plate Fig. XXV Having observed what has been said touching the three first Points of the Preceding Curtain take the Extremities of the Curtain BC and make two Arches to cross or cu● one another underneath and from this Point of the Intersection draw an Arch from one end of the Curtain to the other Lastly There are others that form the Curtain of a Circular Figure without side like that which is mark'd D. The Construction of which is like to that which we have already describ'd only that here you make the Intersection above the Curtain in E From which Point you afterwards draw the Arch from one end of the Curtain to the other The Breast Curtains are those which are drawn streight out-right from one Flank to another See the same ●lank P● at the end of the third Book Fig. XXVI CHAP. VI. Of the Parapet IN regard that this Work is raised to cover the Cannon and the Soldiers which defend the Place it must be allowed a rea●onable heighth and breadth Cellarius allows it six Feet in heighth with a Foot of sloping within side● to the end the Soldiers may be able to stand the better when the Parapet is reared after that manner The heighth without side from the Cord●n ought not to be above four Feet because the ●loping which is made by those different Heights inward and outward gives the Soldier an easier view of the Covert-ways and the Moats that are before him As for the Thickness of the Parapet Monsieur Clermont allows it for the Basis the third part of the Basis of the Rampart The Count de Pagan makes it three Fathoms broad Of which opinion are several others as Goldman Fr●ittag and Monsieur Vauban himself So that we may boldly say That the Thickness of the Parapet is good when it is not less than 18 Feet nor broader than 24. For being weaker the Parapet cannot long resist the force of the great Shot which would soon level it with the Earth● and being thicker it would hinder the Soldiers from the sight of the Moat and the Covert way If you would line the Parapet it must be allowed a little ●loaping that the Soldiers may have the better footing The best Lining of Parapets is with Turf As for the Earth or Mould which you are to make use of in erecting a Parapet it is very requisite to mix it with Withy Twigs or Brambles and to sow it with any Weeds that take a deep root to bind the Earth together so that the Cannon may not easily crumble it down Hay of Burgundy is also very good for this purpose in regard that there is no Plant that puts forth more or deeper Roots CHAP. VII Of the Banquets AT the foot of the Parapet upon the Plat-form are usually made two little Steps or small Banks of which the first is about two Feet broad Goldman makes it four Feet Fr●ittag 3. the Count of Pagan 2. Monsieur Clermont the same and one Foot and
but little expos'd so neither do they not survey very far and it is impossible to make good Embrasures upon a Parapet ordered after that manner For to play the Cannon above the Parapet is to make it impossible to preserve it in a good condition besides that a Flank disposed after that manner can never defend the Passage of the Moat nor flank the Breach nor in the last place uncover the covert Ways As for Monsieur le Chevalier de Ville who makes the Flank perpendicula● to ●he Curtain he has more Reason for what he does than Erbard though his Fla●ks are less than those which Monsieur Vauban makes use of and that they do not batter the Moat sufficiently nor the Counterscarps which is the most essential part of the Defence Besides it is but too well found by Experience that when the Counterscarp is gained the rest holds out but a short time the Reason of which if it be demanded is because the disposing of the Places is so disadvantageous that one Day sees them reduced to D●st and the Embrasure● made upon these Parapets perpendicular to the Curtain are too acute especially if it be required that they should clear the covert Ways I know it may be said that it is easie to m●ke an Orillon or Ear and a retired Flank in a circular fashion But the Orillon will be too feeble unless you allow it the half of the Flank and the remainder will not suffice for its Defence not having room enough for several Pieces to be placed upon it besides that there must be a mixture of great and small Shot which will cause an inevitable Trouble Monsieur Pagan a Person experienced to perfection in the Art of War and one who has jus●ly acquired the Reputation of being one of the most skilful Engineers of our Time was the first that alter'd the disposing of Flanks perpendicular to the Curtain by allowing them much more overture for he makes them perpendicularly upon the Line of Defence and he gives very good Reasons for it in his Book of Fortifications where he says That his being present at above twenty Sieges convinc'd him that Flanks perpendicular to the Curtains were of little dura●ce And he wonders that the Reputation given to the Holl●nders for their Perfection in the Art of Fortification should be so great ●ince the Places fortified according to their Method make so little Resistance and for that there is not one which is well defended from the Canon Nevertheless● we may presume to say that Monsieur Pagan'● 〈…〉 altogether without defects for the Enemy 〈…〉 nk so dispos'd before he comes upon the covert 〈…〉 ●efore to make the best of all the Advantages wh 〈…〉 one and the other produces in his defence Monsieur Vauban allows an Overture to this Angle from 98 deg to 106 as may be seen Book IV. C. ● Sect. 3. For by this means the Embrasures made in the Pa●rapet in this Flank perfectly uncover the Moat and the covert Way And though Monsieur Vauban should not have made this Flank in a crooked Line by means of the Orillon and the retired Flank however it ought to be preferr'd before others because the Ravelin covers the Overture which is allowed it above the Perpendiculars to the Curtain and consequently it is not too much exposed b●●ides that it considerably enlarges and diminishes the Faces which are the weakest Parts of a Fortification CHAP. II. Of the Flank HERE we must repeat what we have already said That though the largest Flanks are the best nevertheless it is a Thing disputed among the Engineers Morsheuser made th● Flank to a Square of 16 Fathoms to a V of 18 to a VI of 20 to a VII of 22 to an VII as far as a Dodecagon of 24. Freittag made it to a Square of 12 to a V of 14 to a VI of 16 to a VII of 18 to an VIII of 20 to IX of 22 to X of 24 which Length he retains also in Polygons of 11 and 12 Bastions Goldman made it a Square of 12 to V of 16 to VI of 1● to a VII of 20 to an VIII of 22 to a IX ●ll he came to Polygons of 12 Bastions of 24 Fathoms In general the H●llande●s make their Flanks to a Square of 16 Fathoms 2 Feet to a V of 18 Fathom 2 Feet to a VI of 19 Fathom 2 Feet to VII 19 Fathoms 5 Feet to an VIII 2● Fathoms 1 Feet● to a IX of 22 Fathoms 1 Foot and a half to a X 23 Fathoms 2 Foot to XI of 24 Fathoms 2 Feet Monsieur the Count of Pagan allows the Flank in a Square 19 Fathoms 1 Foot● to a V 24 c. as you may see L. 3. C. 16 17. CHAP. III. Of the Faces AS the Face is the most dangerous Part of a Fortress and for that it is ex●reamly expos'd to the view of the Enemy 't is requisite that it should be as short as may be for that by how much it is the more advanced towards the Field by so much it is the more liable to be at●ack'd Whence it c●mes to pass tha● the Enemy of ●●●e generally makes choice of that Part to begin his Breaches As to the length of the Faces the Engineers differ as much one among another as they do about the Flanks Adrian M●tins would have the Face to carry two third parts of the Curtain Monsieur the Count of Pagan allows it in a Square 55 Fathoms and permits the same Length for the Polygons Freittag would have the Face to be always 48 fathoms according to the practice of all the Hollanders As for the Length of the Faces after Vauban's Method● see Chap. 16. of the Third Book CHAP. IV. Of the Orillon and Flank retir'd together with the Brisure or Place where the Great Guns are to be planted AS for what concerns the erecting of the Orillon and Flank retir'd according to Monsieur de Vauban's Method there needs no more than to read what he has written thereupon in the Second Chapter of his Third Book But here is a new Method which though it be not better however it is as good 1. After the Out-Lines of the Fortress are drawn divide the Flank of one of the Bastions into three equal parts and the Face of the opposite Bastion into two as A ● B C. 2. Draw from the Point B which makes the middle of the Face a Line through the third part of the Flank which is the nearest to the Angle of the Shoulder D prolonged in the Body of the Bastion of 5 fathoms as DE. 3. Divide this same Third part of the Flank into two equal parts as FG and GD● from which Point G erect a Perpendicular of about two fathoms as GH Lastly Set the Compass upon the Point H and so draw the Rounding of the Orillon joyning FD together 4 Draw from the re-entring Angle of the Moat P a streight Line through the Angle of the Curtain L prolonged in the Body of