Of the Dutch Method, as it is abridged by the Emperor Ferdinand the Third; with an Account of the Construction of the Fortifications at the Grave in Holland. Plate 1 Figure 3.
THe Dutch have been as famous for their experience in Fortification, as their Coun∣trey at present is for their fortifyed Towns; and by their Engineers, as Dogen, Marolois, &c. have filled the World full of their Books, and ways of Fortifying; altho they might have saved them∣selves the trouble, and laborious pains in cal∣culating Triangles, and other Mathematical Learning, more for curiosity than use in this mat∣ter. For which reason the Emperor Ferdinand the Third found out Rules approved of, by turn∣ing their Fortifications out of the way of calcula∣ting Angles into Lines. He sets down this univer∣sal way of drawing the Lines of any Fort.
'Tis to be taken as a Rule, That if the Interior Polygone be 66 of any Measure, the Gorge must be 15, the Flank 12, and the Capital 24.
Now in proportion according to the second Maxim, If the Polygone be 720 Feet, the Capital will be 261 Feet, 9 Inches, the Gorge 163 Feet 7 Inches, the Flank 130 Feet 10 Inches, which is to be set at right Angles with the Curtain; thus by taking of these proportions from the Sector, you may fortify any Figure according to this Method.
This is an abridgment or Epitomy of all the Dutch Fortifications, except the Square, which hath no second Flank.
See Schottus Edition of Amussis Ferdinandea.