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.

V. To turn a Prism or a Cylinder into a Py∣ramid or a Cone of the same height, or the contrary.

1. Enlarge the Base of the Cylinder three times as much as it is, by Prob. 1. Chap. 2. Book 1.

2. Upon its Center raise a Perpendicular as high as the Cylinder, and draw the ex∣tremities of the Diameter together to the top of the Perpendicular, and the Pyramid will be made: In like manner you may turn a Cylinder or a Prism into a Cone: On the contrary, when you would make a Prism or a Cylinder equal to a Pyramid or a Cone, you must make the Base of the Py∣ramid or of the Cone three times less, and

then upon this Base erect a Cone or Pyra∣mid of the height of the Prism or Cylinder given.