Discourses on Fortifications

does what is appropriate, as by another means one can penetrate a bastion much more than six rods with batteries; and the usual flanks do not suffice to defend a fortress in such a way that the enemy cannot get underneath it. Nor will I bother to discourse any further, because even though there are many other opinions, some of which want the orillon to open so much that it goes to the line of the low part of the exterior angle of the opposite bastion, and some of the upper parts of said angle, which comes further inward due to the scarpa slope; others of some part of the faces of said bastion; and others, that it is formed in such a way that from the entire length of the flank the counterscarp can be cleared. Nevertheless, the more they seek to refine themselves to reach defenses, the more they subject themselves to new defects. Therefore, to say briefly what I think, I would resolve to make the shoulder parallel with the curtain that comes between the bastions, so that the high flanks would not be seen much even from the side, and I would make the orillon only so open that it would not force the high defenses to come from further inward. I would want it to protrude outward enough to ensure that, on this side, if it were struck, the defenders would not be hindered or disturbed by some ruin of it in the low plazas and those open at the top. And in this manner, a large part of the low flank would not be seen much from the side. Furthermore, I would want all the parapets to be made of earth, to make them even less subject to being enfiladed or ruined. And even if it were true, as it seems to many, that that little space of the flank of the high plaza which is hidden by the shoulder could not serve, I would not only acquire it in another way but add more and better defenses with less expense. And this can be considered in the plan and elevation, where I will treat the new way of fortifying. Now, leaving aside the effect of the orillons regarding the covering of more or less of the length of the flanks or the void of the embrasures that are made there, one must know that the orillons have been made in different ways, as is seen in the following plans. Round ones are praised by many to avoid corners. Others, for less expense, would want them in the way marked A, and I would make them either round or as seen in the plan B. Because that inner corner being reduced to a round shape, the enemies will have less hope of being able to make the struck stones fly by beating on that part, in order to trouble the defenders of the plazas. And if the other corner remained, I would care little for it, being able to contribute little more expense and no harm because of it, since it is obtuse and capable of making much resistance, especially since in such a part, when the shoulder is thick as is fitting, the enemies are not accustomed to, nor should they, strike; of which I do not want to give a reason now, as it is not to the purpose of what I am treating in this place. Nor do I want to refrain from saying how some are of the opinion that the orillons should be made as high as is enough to cover the low flanks, perhaps for less expense and because they are not necessary in the high flanks, since the shoulders have the same effect in them. But since the enemies can, by striking the shoulders at the angles that come above the second plazas, disturb the defenders who are standing there, it seems to me that the orillons should be made as high as the bastions.

A geometric diagram showing two bastion designs labeled A and B, illustrating the angles of the flanks and the shape of the orillons.

Now, even if from the above-mentioned things one can easily understand that every flank is divided by common practice into two parts, namely, the plaza and the shoulder, it is nevertheless to be known how much space should be given to each of them. For some have divided the length of the flank into three equal parts, and some into two, and some of the four parts have left only one for the shoulder, and some have given it half, and some two-thirds. Wherefore, having finally considered how important it is to secure the plazas, whose principal security arises from the thickness of the shoulders, almost all observe this last way. But because the plazas could still suffer other disturbances, for which it was not so easy to find the remedy, to avoid many inconveniences and cause that good which I have said elsewhere, even if the opinions of the majority have been in agreement in making three plazas per flank, they are then different in arranging them and forming the results. For some, by raising the low plaza from the plane of the ditch by ten to fourteen palms, and adapting two or more cannoniere gun ports in it to make the smoke exit more freely, have covered only that half above which joins with the face of the flank, leaving the other half on the back side open; which displeases me. Because besides the smoke that would come from the second plazas, the smoke of this plaza would also doubly impede the view of the higher flanks, which already have too much to do to secure themselves so that they are not uncovered by those outside, without new impediments being added to them. Wherefore, because in the middle plaza, due to the little recoil space they give it, one could not use large pieces, and the low defense, due to its lowness and the ruins