Discourses on Fortifications

To speak even more minutely of the flanks, I am forced to discourse first upon the following particulars.

A geometric diagram showing a cross-section of a fortification wall with labels N, O, P, Q.

It was customary in the past, and not long ago, to make bastions hollow on the inside, even though metal artillery had been invented; and in each of them, two or three levels were made. If one wanted two, a vault was built over them which came to be level with, or a little higher than, the plane of the ditch. If one wanted three, the middle one was covered with another vault, which made the third level above. And in each of these, two bombardiere embrasures for artillery were adapted for each flank, making use of those that were covered by the depth of the ditch to clear the enclosure of the fortress, the ditch, and the counterscarp outer wall of a ditch; and of those that were higher up, to uncover the countryside outside the ditch as well, just as I have demonstrated in the past discourse. A short time later, even though the bastions were made large and with thick walls, they nevertheless seemed to remain weak, for being, as I have said, hollow. Indeed, it was clearly recognized that they were almost entirely useless, because one could not make a retreat there, nor stand in battle; and while they were under fire, the trouble caused by the stones, which bounced when struck by enemy artillery, and by the vaults, which were deafened and shaken by them, and even by the weight and tremor caused by the artillery that was used inside, was such that one could not safely stand either above or below. Besides this, in the levels covered on the top side, the smoke would become trapped in such a way that the vents established for this purpose did not suffice to allow any person to stay there, except with great difficulty; and not making orecchioni orillons/rounded projections, the entire length of the flanks remained completely uncovered, which gave the defenders great convenience with their fire to make them useless. Wherefore, to avoid so many inconveniences, now commonly the bastions, and the curtain the wall between two bastions which comes between them, are made large and completely earth-filled up to the level of the upper plaza. In these, they leave off making embrasures for the face from the cordon downwards, not only for less expense, but to make the shelter more unified, and consequently stronger; and for each flank, as much hollow space is left as suffices for the low plazas, as is seen by the space marked A in the following bastion; and these are made open at the top, and as high from the plane of the ditch as the counterscarp, or a little more or less. And because the part marked B, called the spalla shoulder, is also earth-filled like the rest of the bastion, and parallel with the curtains that come between the bastions, it follows that from the greater part of the length of the high flanks, one can clear the opposite bastion with less impediment.

A geometric diagram showing a cross-section of a fortification wall with labels A, B, C.

And yet, by providing for this in such a way, many have believed that it would not be necessary to make orecchioni orillons, since the low flank seems to be covered by the ditch and the embankment. But since the enemies can cut the embankment and uncover the length of the flank even from the side, it seems to me that to cause other good effects in the second plazas, which I will demonstrate hereafter, the orillon is necessary. Even if many cannot deny this, there are nevertheless many disagreements among them. Some would want it, but not parallel with the curtains between the bastions, so that the shots do not have to come from further inward, and consequently the ability to harm, or to give more trouble to those enemies who persuade themselves to stay safe within a battery, however small, is not taken away from them. Others say that it should be made in such a way that, as I have said, it better secures a part of the low flank, and that it does not matter if the defenses originate from further inward, especially those above, which would come from further inward every time the orillon followed the line of the shoulder. For they say that, with the bastion standing, every shot is enough to clear it, even if it came from far inward; and that space of the flanks which is hidden will serve when a battery is made in the other bastion, or when that part of the flanks which is uncovered from the outside is brought to an end by the enemies, so that it can no longer do its duty. For then, by striking with the artillery from that space into the face of the bastion near the demolished part, one would harm the enemies as much as possible. Others then labor to oppose this, saying that if a battery, however large it has been made, is not accustomed to penetrate more than six rods, it should be enough that both the shoulders and the orillons are made in such a way that their inner part goes in line with those six rods; and thus the defenses would not have to originate from so far inward. But because one could say much about this, and it would help little, I will leave it for now in consideration for whoever