Instruction on the Fortification of Cities

Now that the flat ground plans of these bastions have been shown, one must proceed with raising the building. First, look at it from the side through the cross-line i.h.k. Place this line as a base foundation with all its points, which indicate the thickness of the curved and straight walls, as well as the width of the spaces between them, together with their corresponding letters. Let i. come first, h. in the middle, then l.m. come to a point at the rear. Thereafter, draw an upright line upward from point h. at right angles, seventy feet The original term is "schuch" (shoe), a historical unit of measurement roughly equivalent to a foot. high; at that height, place an A. This indicates how high the building should rise to where the top level shall stand. This structure must be high because it stands deep in the ditch; it should also rise above the city wall so that one may shoot from it in all directions. However, circumstances may arise where such a bastion must be made higher or lower.

Next, take the line i.h.l.m. from the top ground plan with all its points, as it was drawn from the longer bottom line of the plan, and lay it transversely with its point h. at right angles at point A. Then draw straight lines from all points of the transverse line of the lower plan to all points of the transverse line of the upper plan, so that i. meets i., h. meets h., and l.m. meets l.m. From this, one finds the thickness of the walls and the width of the spaces between them, as they narrow toward the top.

But for the slanted walls, when viewed in section from the side, the stone angles should be cut correctly, just as the middle wall d.e. is cut through its layers. Therefore, in building upward, depending on whether the walls slant much or little, all stones should be laid at right angles upon their beds In masonry, the "bed" is the horizontal surface on which the stone rests.; thus all these things press into the reinforcement against the middle wall d.e. This is good against artillery geſchüß Dürer refers to heavy cannons and the projectiles they fire., for the wall cannot be easily knocked inward. But in the round walls, when viewed from the front, the stones should be cut so that their sides are directed toward point f., so that they fall correctly into a circle, along with their cross-reinforcing walls. These stones should be locked into one another very masterfully when set; skilled stonemasons know well how to do this, so it is not necessary to write further of it.

Also, if one wishes to make the battlements zinnen The defensive parapets at the top of a wall with gaps for firing., they should be set nine feet high. One may also cover the top of this building with sand and lay broad paving stones over it, so that the shot damages the building less. However, it is better to cover the top of the bastion with squared oak beams, one foot apart from each other, with thick planks nailed transversely across them. This must all be perfectly level Original: "wag recht," meaning horizontally level.. For if the wheels of the artillery do not stand level with each other, it is impossible to shoot accurately from them; such a wooden platform also holds up well and carries great weight. This plank-work takes up approximately two feet of the height; thus seven feet of height remains for the battlements. Behind these, any upright man may easily have cover for shooting.

But the battlements shall be made thus: draw the line of the forward round walls nine feet high inside, according to how it slants; there, place a 3. Then place a point on the transverse line i.h. nineteen feet behind the i., and draw a straight line from the 3. to this point. This is how far the battlement wall should slant backward into the building at the bottom, but at the top, it leans outward toward the ditch; thus it stands firmly. Then open a compass zirckel nineteen feet wide and place one foot of it on point 3. and the other inside on the line of the slanted walls; mark that spot with an x. Hold the compass steady there, and with the other foot, draw a curve down from 3. toward i. If, however, the battlements should be made two feet lower, so that the shot has even less chance of hitting the edge Original: "prellen," referring to the ricochet or impact of incoming projectiles., that may certainly be done. However, the compass for the arc must then be moved to point r., as I will show in the drawing. If one wishes to finish the battlements entirely flat according to a straightedge, as mentioned before, that may also be done. Whoever wishes to stand freely under the sky without any defensive walls may do so, provided that the breast-wall at his feet is below twenty-three...