Instruction on the Fortification of Cities

...heavy items that are in the ditch and for other necessities. It shall be made thus: one should proceed from the ground in the angle of the other round walls upwards with a vertical line ten feet high. From the height of this line, one should proceed with a horizontal line at a right angle inward to the front curved wall; from there, the wall should be led with a vertical line straight down to the ground; thus this passage will be approximately fifteen feet wide.

After that, place one foot of a compass in the middle of the ground on the horizontal line, across the width of the passage, and with the other foot draw a circular arc original: "zirckelriß" from one vertical side of the passage to the other; thus the passage will be more than twelve feet high. This passage should be vaulted and led all the way around; but through the cross-walls, make the passages nine feet high and seven wide, so that one can easily pass through with equipment equipment: "zeug" refers to artillery pieces, their carriages, and necessary military materiel. These vaults should be closed everywhere with triple-layered long ashlar blocks ashlar: "quaderstucken," large square-cut stones set into one another, or walled with bricks nine feet thick, for it must carry the entire load that lies upon it.

If one wishes to close the vault through the cross-wall even more thickly, this should be done with another long ashlar. And of all the vaults made below in this building, none should be closed less than nine feet thick for safety's sake, for the powerful vibration of the shots that occur upon it will be mighty, as will be the enemy's battering original: "anklopfen," literally "knocking," referring to the impact of enemy projectiles or siege engines against the walls.

The vaults for the flanking defenses flanking defenses: "streichweren," defensive works positioned to fire along the face of a wall or ditch should be strongly joined into the vault of the circular passage; or, behind the vaults of the flanking defenses, one should make higher cross-vaults in the passage, closed as strongly as possible, and let the depth at those places extend into the wall. Note also that the vaults above the flanking defenses must incline inward with the course of the stone walls, and they should be made twenty feet high at the front on the inside, but lower at the back according to the slope of the stones.

However, so that the smoke may have its exit when one begins to shoot, it is necessary to make chimneys chimneys: "schlot," vents for smoke and air-holes below them, for without such things one cannot remain in the vaults; these, along with the chimneys, must have a good width; therein, these smoke-holes and chimneys should be made round and four feet wide, reaching out from immediately beneath the vault of the lower flanking defense. But the chimneys are to be built round, like one makes wells, straight through the vaults as high as is necessary to exit at the top of the walls, and this same exit should be very strongly protected; also, one should place grates over such smoke-holes.

How wide the flanking defenses may be and what their form shall be, I will indicate later when I take up the lowest ground plans again. Now, observe how the stairs in this building should be made. First, take note: if the ground within the city lies high against the building, the bastion bastion: "pastey," a projecting part of a fortification should nonetheless not be raised to a height of twenty-eight or twenty-nine feet. However, as one decides at each location and as necessity necessity: "nottorfft," the specific tactical and geographical requirements of the site requires; but from the depth of the ditch there should always be a great height up to the bastion, just as I have previously assigned a height of seventy feet by way of example; not because that exact height must be used in all places, but rather it may be determined according to each person's necessity.

But if the pavement in the city is high against the bastion, as previously mentioned, then one requires in the building—between the two nearest straight walls toward the city on each side—two broken stairs Dürer refers to "gebrochen stigen," which are stairs that turn or have landings, rather than a single straight flight. built one above the other. Thus, one flight will be approximately fourteen feet high and provide twenty steps steps: "stapfeln," the individual treads of a staircase. And if one has such high ground to cross from the city into the bastion, one must lead strongly vaulted passages from the two stairs on both sides between the two straight walls, nine feet high and five wide, as far as the side walls. From there, one leads three broken stairs down on each side to the flanking defenses; thus, one staircase will be about twelve and a half feet original: "drenzehthalben," an archaic way of saying 12.5 (half of the thirteenth). high; from this, one makes eighteen steps. If one desires a gentler gait original: "senfftern drit," a more comfortable or shallower climb, then one should divide it into more steps, or make the stairs so that they [continue] in the passage on both sides...