Fortification or Military Architecture

A 2

A rectangular inset plate titled "Page 9" contains several geometric diagrams with labels translated from the original Latin:

• Top row: A curve, a plane surface (represented by a rectangle), and a line that is both straight and curved.
• Second row: Curved lines, mixed lines (combining straight and curved elements), and straight lines.
• Third row: An obtuse angle, an acute angle, and a right angle.
• Fourth row: A semicircle, a circle showing the diameter, and a circle showing the radius.
• Fifth row: Triangles categorized as scalene (unequal sides), isosceles (two equal sides), and equilateral (all sides equal), followed by a rectangle.
• Sixth row: An obtuse-angled triangle, an acute-angled triangle, and a right-angled triangle.
• Seventh row: A rhomboid, a rhombus (lozenge), and a square.
• Bottom row: Diagrams illustrating complements about the diameter, parallelograms, and parallel lines.

...has only two parallel lines
but they are irregular, namely of
e 16.
sides and angles equal to each other, like-
...and 26. Figures, and on plate 13.
sides and angles unequal.
the foundation of a triangle, of a...

...extremity of a straight line which,
until it is returned to where it [began]...

...of the circle, the line described by the [circumference], and all the lines drawn from the [center] called Radii original: Raids, an archaic French term for rays or radii.
...passing through the center, ending at the [circumference].
...made of two radii making an angle, [the line between the] radii is called the base of the sector, as [the minor sector].
...of the same circle, comprised of [an arc] and a straight line, which is called [a chord], greater and lesser section.

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Parallel circles are those which are concentric, that is to say, which have the same center; see figure 22.

An angle in the circumference is that which has its vertex on the circumference.

The oval and the ellipse are different things, for the oval is a figure made of several parts of the circumference of a circle, as in figure 34; but the ellipse is a simple Figure having no part of the circumference of a circle, such as the section of a Cylinder (33) and of a Cone (35). However, figures 35, 36, and 41 are poorly drawn, for they ought to be the same on one side as on the other, contrary to the opinion of Marolois Samuel Marolois (1572–1627) was a Dutch mathematician and military engineer whose works were standard texts in the 17th century. and many others.

A parabola is a section of a cone, created when the cutting plane is parallel to one side of it. See figure 37, 38. B G C.

An hyperbola is a section of a cone when the cutting plane can cut only one side, even if the plane and the cone were produced to infinity, without however being parallel to the side of the cone. 39. 40.

A spiral is a figure generated by the movement of a point along a radius while it describes a circle, with the whole movement being uniform and finishing at the same time. 42.