called La cunette out of the great ditch and with the earth that is taken out of it you are to erect the brest-werk of of your Contre escarpe with the foot-step of it the height of which is to be six foot high with the foot-step from the ground and foure foot and a halfe from the footstep and the top of it sloped to nothing and levelled with the firm ground leaving six places of twelve foot broad to place six Turn-Pikes right against the middle of the six Halfe-moons that are to be erected after the brest-works of the Contre escarpe are finished the distance between the brest-work and the brim of the great ditch is to betwelve foot at the least and these Turn-Pikes are all of them to be locked in the night and serve to retreat or releive the Out-guards in time of a siege And when all this is perfected you are to set out the six Out-guards that are six Halfe-moones in the form of six equilaterall Triangles that have all their sides equall of one handred and forty yards apiece their Base that lieth towards the Contre escarpe is to be open and the ends of it 20 foot or 24 foot from the slope of the Contre escarpe and the coming to the town and the going out is to be by the South and North Half-moon marked by the letter A. For by this means the gate and draw-bridge will be secured and covered by the Half-moones and the Horse Carts or Foot that come to town shall be inforced to wind about the said Half-moon and by it exposed if they be enemies to the musket shot of them that keep the brest-works of the Half-moones Now to secure these Half-moones from surptises besides the Sentinel Perdues there is to be a small Court of Cuard in the midst of them and strong Pallisadoes with Pallisado gates that extendeth from the Points or Angles to the very brest-works of the Contre escarpe The ditches of these Halfe-moones are to be nine foot broad and fix foot deep their brest-work 9 foot broad in the bottome with their foot-step and their height fix foot from the ground and foure foot and a halfe from the foot-step and their thicknesse at top six foot having a foot slope towards the ditch This Garrison thus fortified and manned with a thousand foot and three hundred horse and provided with 24 peeces of Ordnance Armes Ammunition Fire-works and Victuals and all other necessaries for a siege will be able to oppose an Army of twelve thousand men for 3 months For to conclude this method of Fortification is as convenient for us in these times of civill distraction as any for it is not of great charges and requires lesse men to man the same and yet is safer and stronger three-fold then our skare-crow Mounts small and ill flanked redouts and winding Angles CHAP. XXV Of the fourth and last method of Fortification by small Flankers in generall THis fourth and last method of Fortification is derived from the first composed of Flanks Courtines and Eastions without Orillons for they agree in their form but disagree in their dimensions the faces flanks and brests of these flankers being in a manner halfe as short again as those of the Bastions the extent of the Courtines of this method by * A Flanker is properly a bastard Bastion without Orâ—llons flankers longer by forty yards by reason of the narrownesse of their brests It was invented to save charges both in the erection of the works and in the manning of the Garrisons for I know no manner of Fortifications that will require lesse men to defend it nor smaller charges to erect it then this method and therefore the more convenient for us to make use of it in these times of civill distractions in which we want meanes and time to erect strong compleat and permanent Fortifications and men to man and defend them yet I will informe the reader of this truth that if this method of Fortification be set and lined out by a judicious Enginier and the dimensions of it here described carefully observed that it will be three-fold as strong againe and as permanent and regulary then the Mounts weak redoubts and slight winding Angles used In these dayes And that a valiant and experienced Governour in a Garrison thus fortified will be able to defend it with twelve hundred foot and three hundred horse although it be of three mile and a halfe circumference then he could doe one that I know fortified with Mounts and winding Angles with eighteen hundred foot and three hundred horse So much availeth the Art and the Method of Fortification in the defence of a corporation and yet I dare affirm for a truth that their charges have been greater then if they they had erected such works as these with the very same dimensions following 1 The extent of the sides or Bases of this Method are not to exceed two hundred and fifty yards 2. The neck of their flankers is neither lesse nor exceeds in extent fifty yards 3. The brest of their flankers neither more nor lesse then 60 yards 4. The flanks of their flankers neither lesse nor more then 25 yards 5. Nor the faces of their flankers lesse or more then fifty yards 6. The Courtines between two flankers is not to exceed two hundred yards 7. Their line of defence is to be taken in this method from the middle of the Courtine that it may not exceed one hundred and fifty yards Nor the exteriour Angle of their flanker be more acute then these are 8. The line of their flanks is not to be drawn upon a strait perpendiculary line as most men use to doe for this way is destructive to the flanks and they being reduced to dust the Garrison is lost But they are drawne one â…› part more slope toward the other flank opposite to it that the shoulders of the flankers may be thicker and jet or extend so much the more over the ditches to preserve the flanks 9. All the ditches are to be in this methed that hath no Contre escarpe or Out-guards thirty foot broad and twenty foot deep the slope of them is to be for every yard a foot on every side that the very bottome of them may be sixteen foot and â…” broad for it is a disparagement to make the ditches of Fortifications and Martiall works like the ditches of inclosed grounds besides they are not so safe because they are sooner filled in a storme and this manner of ditches savours over much of the ignorance and selfe-conceitednesse of our country surveyers 10. The brest-works are to be twelve foot high within side and nine foot without side their in-side is to be carried up from the firm ground as well as the out-side and the five foot-steps within side are to be carried up after the brest-work is finished on both sides they are to be two foot * Of the breadth and height of the five foot-steps and of the
allow them to be of 150. square yards that is a piece of ground of twelve yards and halfe square of all sides by which scantling the 41666. yards being divided there will appeare to be in this continent 277. dwelling houses and as many Inhabitants that may billet foure hundred Foot and two Troopes of Horse and this number is sufficient to maintaine this Fort against an Army of five thousand men three months so it be provided with sixteen piece of Ordnance Balls Ammunition Armes Victualls and all other necessaries fit for a Siege Object Some will wonder why so small a Fort should have sixteen pieces of Ordnance when many of our Garrisons that are of two or three miles Circumference have not so many Ans I answer the more is the pity they are no better provided But if this Method of Fortification were not better stored to what end should Forrainers be at the charges to erect upper and lower flanks and because I have not as yet spoken of these upper and sower flanks I will upon this occasion describe how they are made and for what use they are erected In the Ancient Fortifications by Bastions Of the upper and lovver Flanks of a Bastion there was formerly low Casamates to scour the dikes even with the water for they were built so low that a Cannon being mounted in them and pointed shot upon a levell Line even with the water of the dike and these Casamates were all vaulted with arches of free-stone having two Port-holer and two Demy-Cannons in every one of them their vault being some sixteen foot square and they had a slanting descent from the gorge of the Bastion with a door to come down to them but because they had no other light then the Port-holes nor no other evacuation for the smoke then the doore when the Cannoniers fired their Pieces they were so incumbred with the smoke in the vault that they could not suddenly charge their pieces againe but were inforced to sâ—ay till the evacuation of the smoke were past Whereupon the moderne Enginiers to prevent these defects have invented the upper and lower slanks where they alwaies place two pieces of Ordnance in everie one of them so that according to the Forrain Method every Bastion is to have ten pieces of Ordnance at the least two Demy-Cannons in everie flanke and two long Culverins to defend the faces and the point that is in all ten pieces of Ordnance these Flanks are made after this manner The wall of the flanks is brought up from the bottome of the dike with free-stone of two yards thick to the levell of the water of the dike and within and without laid with Tarris that the water of the dike may not pierce the same and upon this wall and the firme ground after another foundation of stone hath been laid twenty four foot from the brim of the first wall some five foot deep a Brest-work is brought up of earth and turfe of twenty foure foot thicke in the bottome and of twenty foot broad at top and six foot high having three Port-holes and beyond this Brest-worke the ground is digged lower the whole length of the flank that is ordinarily from thirteen yards to sixteen yards in length and in breadth eight yards and in depth five foot and this being laid with tracin and planked is the Platforme of the lower flanke open over-hâ—â—d in which they place two Demy-Cannons and these scouâ—â—â—â—d free the dikes from the assay lants galleries and from the scaling of the Rampiers Now to erect the upper flank they go eight and forty foot wider into the gâ—rge of the Bastion and upon the in ward foundation of the lower flanke wall and the earth of the Bastion they erect another Brest-work of the same height bredth and thicknesse of the former with three Port-holes in it and then they planke another platforme and place two Demy-Cannons more upon the same and these are the manner of their upper and lower flanks that have a slope coming downe from the upper to the lower some ten foot broad which being covered by the Orillons make the Bastions very strong and when these double flanks are taken out on both sides the gorge is not above fiftie yards broad that is narrow enough for the last re-intrenchment Now these flanks being all open over head the smoke of the Ordnance is suddenly evacuated the use of the upper Flank is to scoure the face and the points of the Bastions in the time of a storme and to beat all along the Courtine And so much will suffice once for all concerning the erection and use of these lower and upper Flanks Now I come to shew how you are to set out this Square in the field If men could as soon and as easily set out a Superficie in the field as they may upon paper it were soone done but this last requires a greater labour and care You are then in the first place to make choyse of your Center and there to knock in a stake then you are to stand close to that stake and turne your face full South and then take your Demi-circle and set the sight of it upon the ray of 90 degrees that is the Angle of the Center of the Square then you are to have two men by you one with lines and the other with stakes and he with lines is to have a line of one hundred and * You are to observe that this line of 180 yards is the just demi-diagonall line and distance that is betvveen the Cent r-stake and the Angles of the Square fourescore yards the one end of which line he is to fasten to the Center-stake and when you have taken your Demi-circle and set the sight of it as afore-said you are to take with it having your face turned to the South the right hand ray of the Angle of 90 degrees and when you have it let the man straine the line fastened to the Center-stake along the said ray to the end of the line and when he is just against you and the ray of your Demi-circle let the other man knock in a stake at his feet then turne your selfe and set your Demi-circle to take the left hand ray of the angle of 90 degrees and when you have it let the man with the end of the line come to it and when hee is just against you and the ray of your Demi-circle let the other man with stakes knock in a stake at his feet at the end of the line and these two stakes represent the South-East and the South-West Angles of your Square then turne your selfe fall North standing close to the Center-stake and set out after the same manner the North-East and North-West Angles of your Square and let the man with stakes knock in two stakes as hee did in the South side and these foure utmost stakes will represent the foure Angles of the Square Now to avoyd errour you are to fasten the
knock in a stake at his feet and this stake will represent the North East Angle of the Poligon then turne your face to the North-West and with the ray of your demy-circle on the left hand the man with the line following the same and when he is just against you and the ray of the demy-circle being at the end of the line the man with the stakes is to knocke in another stake at his feet and this stake will represent the North West Angle of the Pentagon And after this manner set out the South-East and South-West Angles of the Pentagon and having knockt in stakes these five utmost stakes will represent the five Angles of the Pentagon and by these observations the gate and the draw-bridge of this Fort will be full South and in the midst of the South Courtine to be defended by the flankes of two Bastions when this is done you are to take the line of 250. yards having a loop in the midst which line you are to strain from stake to stake to prove whether your stakes are at an equall distance driving at everie middle of all the sides a stake as you will be directed by the loop fastened to the middle of the line now if any of your stakes be amisse you may easily amend them by the demy-circle and the line and when they are right you are to fasten lines from stake to stake as neare the ground as may be and set many Pioniers to trace the superficie of this Pentagon before you set out the Bastions And this is also the way how you ought to set out the equilaterall Triangle * Hovv to set out an equilaterall Triangle by the demi-circle spoken of in Chap. 12. by the Demy-circle spoken of in the 12. Chapter by driving a stake full North to represent the North Angle of the Triangle and by turning your face South after you have set the sight of the demy-circle upon 60. degrees as being the Angle of the Center of the equilaterall Triangle turning the ray of your demy-circle on the right hand and then on the left hand and driving at the end of the line of 250. yards two stakes for by this meanes the gate and the draw-bridge of the Triangle Fort will be full South and just in the midst of the South Courtine and defended by the flanks of two Bastions The Superficie of this Pentagon being traced you are to divide the five sides of it into six equall parts driving in everie division a stake then you are to fasten to the former line of 240. yards another line of 83. yards and a third that is the just distance from the Center of the Bastion to the utmost point of it and when you have done so you are to fasten the same to the Center stake and to straine it diagonall-wise 83. yards and one third part beyond the five Angle-stakes making the line as you straine it to touch the said stake and at the end of the line to drive in five stakes that will represent the five utmost points of the five Bastions And for the setting out of the rest I referre you to avoid repetition to the two last Chapters where you had large directions to set out the flanks and faces of the Bastions with their Orillons Dikes and Conterscarpes and will onely acquaint you with the demensions of this Pentagon since I did omit the same in the square yet I will give a hint of them in this place the flankes of the square were but forty yards and the flankes of the Pentagon are forty one yards and two third parts their Courtines are alike of 166. yards and two third parts the distance from the Center to the point of the Bastion in the square was 86. yards and in this Pentagon of 83. yards the gorge of the Square and of the Pentagon alike of 83. yards and one third part And the line of defence in the square 230. yards and in the Pentagon three yards lesse The faces of the Bastions in the square of 105. yards and in this Pentagon 100. yards and the brest in the square of 95. yards and in the Pentagon 100. yards CHAP. XV. Of the Fortifications of the Ovall by Bastions without Orillons demonstrated in Plate 8. THe Ovall is as irregularie as the Triangle and one of the most difficult superficies to set out in the field because of the circulary form and the variety of the Angles foure of them being of sixty five degrees and two of thirty seven degrees and a halfe the Angle flanking of 130. degrees and the Angle flanked of 72. degrees and a halfe her circumference is of 1500. yards and her continent from out to out of 118800. yards out of which the one third part being defalked for the bredth of the Rampiers the market-place and the streets there remains for the houses of the Inhabitants 79200. square yards that is to be divided by 150. square yards for a piece of ground of 12. yards and halfe square of all sides that is allowed to everie one of the Inhabitants that are found to be by this calculation 528. that are to billit 176. horse-men and 704. foot-souldiers A sufficient Garrison to oppose an Army of eight thousand men for three months so it be provided with Cannons Ammunition Armes Victualls and all other necessaries for a Siege It is also a convenient superficie to fortifie a well-compacted market-towne that may be reduced to this forme of three fourth parts of a mile Circumference Now to set out the Superficie in the field Note once for all that you are to have a Sea-compasse vvhen you go about to set out any kind of Superficies in the field to place your angle South North East and VVest rightly you are to make choice of your Center and to drive in a stake and to fasten a line of 80 yards to that stake and to straine the same full East upon a strait line and to drive in a stake then you are to wind the line about and to straine it full West and to drive in a stake and these two last stakes divide the length of the Ovall into three equall parts of 160. yards a piece and represent the two Centers of the two circles out of which the Ovall is formed then you are to fasten a line to the Center stake of 220. yards that is the extent of the demy-diagonall line of the South-East and North-East Angles and of the South-West and North-West Angles that are of 57. degrees and a halfe upon theray of which Angle you are to set the sight of your demy-circle and standing at the Center stake to turne your face full East winding the ray of the circle on the right hand the man with the fore-said line straining the same till he come just against you and the ray of the circle then is the man that carrieth the stakes to drive a stake at his feet then you are to winde the ray of your
demy-circle on the left hand and to do as you did at right hand and at the end of the line to drive in a stake and these two stakes will represent the South-East and the North-East Angles of the Ovall then you are to turne your selfe full West and to set out with your demy-circle and the fore-said line the South-West and North-West Angles driving two stakes at the end of the line Then you are to fasten a line of 160. yards * This is the extent of the demi diametricall line of the bredth of the Ovall to the Center stake and to straine the same full South upon a strait line and at the end of the line the man with stakes is to drive in a stake then wind the same line about and straine the same full North upon a strait line and at the end of the line drive in another stake and these two last stakes represent the South and North Angles of the Ovall then remove this line from the Center stake and fasten it to the East Center circle stake strain it full East upon a strait line and at the end of the line drive in a stake then remove the same line to the West Circle Center stake and straine the same full West upon a strait line and at the end of the line drive in a stake and between these eight circularie stakes consists the superficie of the Ovall Now because the six sides of it are circularie you are to remove the fore-said line of 160 yards to the Center-stake and to fasten your iron tracing-pin to one side of the line and the other side to the stake and to straine the same full South and to trace the ground as far as the line will give you leave on both sides of the South stake and then you are to do the like on the North side and that being done you are to fasten these lines one after another to the East and West circle Center-stakes and to trace the West and the East sides of the Ovall with the point of your iron pin as you did the South and North sides joyning the tracing of your pin on all sides and this being done you are to set many Pioniers to make the tracing deeper with spades or with the flat ends of their pick-axes And when this Superficie of the Ovall is sufficiently traced you are to divide the six circularie sides into six equall parts driving a stake in everie division then you are to fasten a line of 85 yards to everie Angle-stake one after another and to straine the same upon a strait Diagonall line from the foure Angle-stakes that represent the South-west and North-west and South-East and North-East Angles but upon a strait Diametricall line from the South and North Angle-stakes and at everie end of the line you are to drive in a stake and these six stakes will represent the six vtmost points of the six Bastions then you are to fasten a line of 240 yards to everie third stake of your six sides to set out by it the faces and the line of defence of the Bastions by straining and fastning this line to everie Angle stake twice to set out the twelve faces then you are to fasten a line of 45 yards to everie second stake of the six sides or bases and to straine this line not perpendicularie-wise as you have done formerly when you did set out the Bastions with Orillons but five yards more bevell toward the next Bastion then strait and where the Line cuts the other that sets out the faces of the Bastions and the Line of defence you are to drive a stake and after this manner set out all the rest till you have gone round Now let me informe you once for all that the safest and the most frugall way to set out your Bastions after your maine Superficie is set out is to set out one halfe Bastion at a time and to have it * A generall observation to be noted presently traced before you remove your Line for these two Lines one long to set out the faces and the Line of defence and a short one to set out the Flanks will serve turne and besides it will prevent all confusion and mistakes Now when all the Bastions are traced you are to set out the dike and when all is finished the Counterscarp as you have been directed Chap. 12 and 13. The Line of defence of this Ovall is of 240 yards the distance from the Center to the point of the Bastion of 85 yards The gates and dravv bridges of this Ovall fortification are to be placed in the middest of the East and VVest courtine that represents the length of the Ovall and not South and North as other Forts are and the length of the Courtine because of her circularie Line of 170 yards the brest of the Bastion 110 yards the Gorges of 83 yards and one third part and the faces of the Bastions of 100 yards and others of 90 because of the winding of the Ovall and her Flanks of 45 yards three yards longer then ordinarie because of the circularie line of the Courtine that it may the better defend the inward Angle of the other Flanks CHAP. XVI Of the Fortifications of the Sexagon by Bastions with Orillons demonstrated in Plate 12. THe Sexagon is regularie and a most compleat Superficie the Angle of her Center is of 60 degrees the Angle flanked of 80 degrees * See in Chap. 18. vvhy these sides have been set out fiftie yards longer then any other formerly have been This Sexagon is composed of six equilacerall Triangles equall on all sides containing everie one of them 39000 yards vvhich being multiâ—lied by six containe 234000 square yards and the Angle flanking of 135 degrees her sides are of 300 yards a peece her circumference of 1800 yards her whole continent of 235000 square yards out of which the one third part being deralked for the bredth of the Rampiers the extent of the Market-place and the streets there remaineth 156000 square yards for the houses of the Inhabitants to whom wee will allow in this greater continent 200 square yards that is a peece of ground some thing more then fourteen yards square on all sides And after this allowance the fore-said number of 156000 square yards being divided by two hundred square yards it will appeare that this continent will containe 780 houses and by consequence so many Inhabitants that are according to the rules of war to billet in everie third house a Horse-man and in all the rest two Foot-Souldiers a peece And after this accompt there will be 260 Horse-men and 1040 Foot-Souldiers a verie compleat Garrison to defend a place not much above an English mile in circumference so it be stored with Ordnance Armes Ammunition victuals and all other necessaries for such a Siege I have in this Superficie as being the last of this Method of Fortification set out the broad streets that go round
about the Rampiers and from the Rampiers to the Market-place that are to be ten yards broad and the Market-place of an hundred yards in her Diametricall Line and of the same forme of the Fortification of the Sexagon for you are to observe in all new erected Forts * The Market place of a nevv erected Fort Citadell or Garrison is to be of the same forme of the out-Superficie of the vvorks Citadels or Garrisons to reduce the Market-place after the forme of the out-side works to be the more compleat viz. if it be an equilaterall Triangle or a Square or a Pentagon the Market-place is to be of the same forme of a Triangle or a Square or a Pentagon Moreover you are carefully to observe to line out in everie one of them broad streets of thirtie foot broad round about the Rampiers and from the Rampiers to the Market-place and these broad streets that run from the Rampiers to the Market-place are alwayes in this Method of Fortification to be upon a strait Diagonall or Diametricall Line from the Center of the Bastion to the Center of the Market-place as these are drawn in this Figure for these reasons 1 The streets round about the rampiers serve for all manner of carriages to be brought to the works and for the Horse-men to ride to the releef of any of the rampiers in the time of a siege or storm 2 The great streets that run from the * For vvhat use broad streets lined round about the Rampters and the Market-place are erected Market-place to the Bostions serve for a Troop of Horse of five of a brest or for a Company of Foot with five or six men on a brest to come to the releefe of any of the Bastions that are stormed 3 The Market-place is always to serve as the Randezvouz for Souldiers to gather themselves together to be sent by the Governour where occasion requires I have also set out the order that is to be observed in the erecting of the houses for the Inhabitants that are to be lined out with strait double ranges that gardens or back-sides may joyne one against another that houses may have the more aire and light and that all their doores may open to the streets that are to be fifteen foot broad for narrow lanes are dangerous in Garrison Towns The Store-houses or Magazines of Powder Bullet Fire-works Engins Ladders Pioniers tooles and provision of victuals as Corn Meale Oat-meale Oats Malt Hay Salt Powder Beefe Bacon Dry fish Butter Cheese Rice White Pease and all such necessaries are to be in those houses seated round about the Market-place as the most safest seat of the Towne All these observations are carefully to be regarded if in case the State should erect any new Forts Citadels or Garrison towns where there never was any habitation before for such a new erected Hold would ten times be more serviceable then any old erected Towne in this Kingdome provided all the dimensions of this Method be observed that shall clearly be described in the Ichnography of this Chapter because they are for the greater part of deformed shapes and of a vast extent and not compacted together nor their streets well lined nor ranged in order nor their houses well contrived some of them being verie high and some verie low but these of this new * Of the height of the nevv-erected Houses in a nevv Fort Cittadell or Garrison tovvn erection are to be all alike and not above two stories high that may not exceed with with their roofe thirtie foot high at the most that the ridge of the top of their houses may be lower then the top of the Rampier Brest-work by nine foot Now to set out this Sexagon in the field you are to make choice of the Center and to drive in a stake and to fasten to that stake a line of three hundred yards and a foot over which line the two men that are alwayes to be with you to carrie your instruments lines and stakes are to straine full East after you have taken with a good * An Enginier is never to be vvithout a demi-circle and a good Sea-Compasse sea-compasse the East and West points But if by the long extent of the line the line swags and cannot be drawne strait they are to straine it but one hundred yards verie strait and stiffe and to drive in the ground verie deep a strong stake and to wind the line about it then to strain the line againe another hundred yards and to drive in another stake as before and to * Observe to vvinde the line alvvaies of one and the verie same side of the state to avoid breaks observe to wind the line alwaies of one and the same side and to make it come to be strained againe on that very side you did first wind it upon the first stake to avoid all breakes then you are to straine the line again for the third time and to drive in a stake and this last stake will represent the East Angle of the Sexagon Then your men are to untwist the line from the stakes and to wind it about to the West point and to straine it and to drive in three stakes as they did before and the last stake will represent the West Angle of the Sexagon Then you are to stake your demi-circle and to set the sight of it upon the ray of 60. degrees and to stand at the Center-stake and to turne your face and demi-circle to the East stake winding the ray of the demi-circle East and by South then are your men to follow that ray with the line driving at every hundred yards a stake and when they are at the end of the line just against you and the ray of your demi-circle of 60. degrees let them drive in a third stake and it will represent the East and by South Angle of the Sexagon then turne your selfe and your demi-circle East and by North and set out after this verie manner the East and by North Angle and when that is done turne your felfe full West and set out after this manner the West and by North and West and by South Angles and when all the six angle stakes are driven in Note that a good line of three double vvhip-cord vvound together of 300 yards and a foot having loops fastened at everie fiftie yards and another coloured loope at everie hundred yards vvill suffice to set out all this great superficie then you are to remove your line from the Center stake and to straine the same from Angle-stake to Angle-stake to try whether your Angle-stakes and sides be equall and to amend them if any be amisse by the demy-circle and your line and when they are all equall then you are to fasten this three hundred yard line one after another from Angle-stake to Angle-stake as neare the ground as may be and to set Pioniers to trace that fide before you remove the line and
the Avant-guards is taken from the middle of the Courtine whereby the Line of defence cometh to be from two hundred and fortie to two hundred and fiftie yards but the long Angle Flanks cannot sufficiently be defended by the Musket-shot alone without foure Drakes and foure Sacres one Sacre and one Drake mounted upon everie one of the long Flanks and with them this Fortification will be of great defence The short Flanks are of 60 yards a peece and the faces of the Avant-guards of 120 yards a peece uniforme with the long Flanks To set out this Superficie in the field you are to knock a stake in your Center and to stand close to it and to set your selfe East after you have set the light of your Demi-circle upon the ray of 45. degrees to set out the East and by South and the East and by North Angles as you have been directed for merly and then to turn your selfe West and to set out the West and by South and the West and by North Angles and these bâ—ing rightly set out and stakes knockt in them your two broad sines North and South cannot be amisse But if it be an erected Town take the just length on the broad and end-side of it with a line of 100 yards and set out your Angles with the Demi-circle accordingly and divide your end-side into five and your broad side into ten equall parts and then set out your Avant Guards thereafter CHAP. XXI Of the Fortifications of the Equilateral Triangle fortified by Avant Guards demonstrated in Plate 15. ALL the sides of this Equilateral Triangle are equall and contain 520 yards apiece so that her circumference is of 1560 yards that is an English mile wanting 64 foot the Angle other Center is of 60 degrees I omit her continent because of her large extent that is fitter to fortifie a well compacted town that may be reduced to this form then for a new Fort. Her sides are divided into eight equall parts two of which are allowed for the two brests of the Avant Guards that contain 65 yards apiece and the other six pares are divided equally for the three Courtines that containe 130 yards apiece Her long flanks are 100 yards apiece and her short flanks of 50 yards apiece and the faces of her Avant Guards are uniform to her long flanks whereby they are also of 100 yards apiece And by these dimensions it is apparent that this Superficie is a compact and compleat Fortification because all her Faces Flanks Courtines and Angles can be easily defended by the Musquet shot her line of defence is taken from the middle of the Courtine and by this meanes of 160 yards Yet let me inform the reader that if he had occasion to fortifie a town that might be reduced into this Triangle for me although her sides were from 520 yards apiece to 750 yards apiece that he may boldly fortifie the same after this manner so he divide his three sides into 8 equall parts and doth preportion his Flanks Faces Brests Courtines and line of defence after this extent for notwithstanding this addition of 230 yards to every side of the Triangle all the dimensions of his fortification will be defensible by the Musquet shot Now to set out this Superficie in the field you are to make choice of your Center and to knock in a stake and after to set the sight of your Demi-circle upon 60 degrees and to follow the same directions given you in plate 9 for the setting out of a Triangle fortified by bastions And because these sides are as long againe as they were I referre you to the directions given you in chap. 19. for the straining of a long line by knocking in at every hundred yards of it a stake But if it be an erected town that you are to fortifie after this manner goe up to the end of the town where you intend the North Angle of the Triangle shall be and turn your face South and with your Demi-circle when the sight of it is set upon the ray of 60 degrees set out the South-East Angle of the Triangle cauâ—ing the man with lines to strain a line from the North Anglestake where you stand to follow the ray of your Demi-circle the man with stak s knocking at every hundred yards a stake and by this plurality of stakes you may lengthen your line as you please twisting the same alwayes of one and the same side of the stake till he come to the just distance of your side of the Triangle whether it be five hundred and twenty yards or 720 yards and at the side of the distance knock in a stake and that last stake will represent the South-East Angle of the Triangle then set out after this manner the South-East Angle and knock in a stake at the same distance that it may represent the South-West Angle then measure with a line of 100 yards whether the distance between the South-East and South-West Angle stake is equall with the two other sides and finding it to be equall then is the Superficie of the Triangle perfected that you are presently to have traced by many Pioniers but if there be any errour you are to amend the same by your Demi-circle and your lines The Superficie of the Triangle being traced you are to divide the sides into 8 parts and at every division to knock 8 stakes knocking in also a stake in the middle of every side for it will serve to set out the faces of the Avant guards and the lines of defence allowing two parts to every Courtine and two parts to the two brests of the Avant guards and at every third stake of every side you are to fasten a line of 32 yards and ½ and to strain it first on the right hand along the side traced and at the side of the line you are to knock in a stake and then you are to wind the same line on the left hand and to straine it along the side traced and at the end of the line you are to knock in a stake and these two stakes will represent the breadth of the brest of the Avant Guards the exteriour stake toward the Angles of the Triangle representing the beginning of the long flank and the inward stake toward the middle of the side representing the beginning of the short flank and as you have set out this first brest of the Avant Guard you are to set out the other five after the same manner That being done you are to fasten a line of one hundred * If you can strain a line from the middle stake of the side of 320 yards that is the just distance from the side opposite to every long flank it would â—e the better if not this way will serve turn so you stand with your Demi-circle At the middle stake of the side â—o guide the end of the line of 100 yards to the very out most Point or Angle of the Avant Guard