ON FORTIFICATION

from the top of the frameoriginal: "chaffis"; the structural timber or stone casing that holds the gate.. Now, when the interior water is higher, it presses against the inner side of the gate, and since the iron barrier on the outer side is closed with its latch, the gate E F G H then possesses great stability throughout, enabling it to withstand the pressure of the water without moving. This is because the three sides I F, F G, G H rest against the rebatesoriginal: "feuilleres"; the grooves or notched recesses in the frame that the gate fits into to create a seal. of the frame, as mentioned above, and side E H rests against the post L M. Furthermore, reinforcement is provided by the two bars M N, O P of the barrier, which press against the outer side of the gate. What I have said here regarding one of the pointed gatesoriginal: "portes poinctues"; a type of sluice gate that meets at an angle or pivots to manage water flow. applies equally to the other: namely, that it has a similar frame, a gate turning on a pivot needleoriginal: "efguille"; a vertical rod or spindle that allows the gate to rotate., and an iron barrier.

It should also be noted that these pointed gates on pivots should be no higher than the high-water level intended for deepening the harbororiginal: "Havre"; refers to the process of "scouring" or using a rush of water to wash away silt and sand from the harbor floor., such as from D to A. However, because the entire pointed gate structure must be a little higher—specifically at the height of the Dikeoriginal: "Dicque"; the main embankment or levee.—to resist any extraordinarily high waters that rarely occur, the remainder of the section above A is closed with supports, as seen near S and T. This provides stability to the frame A B C D so that it does not become displaced, which could easily happen if this reinforcement were not there.

To speak now of its use: suppose that the interior water is at its highest and the exterior water at its lowest, and one wishes to open the gates to create depth This refers to the "flushing" or "scouring" action where trapped water is released at low tide to wash out sediment.. For this, nothing more is required than to lift the latch N and turn the barrier as one opens other barriers. Once this is done, and the side F G is free from the barrier L M, the gate E F G H turns very gently on the pivot needle I K until it has made about a quarter-turn. When this occurs, the water held in the reservoir gushes out from both sides of the pivot, deepening the harbor. Then, once both gates and their frames are open, ships with upright masts can pass through. It should also be noted that the flow of water is somewhat obstructed by the two sides A D and Q R, as well as by the thickness of the two gates, which narrow the opening of the Sluiceoriginal: "Efclufe"; a water channel controlled by a gate. by that much. This obstruction can be removed by pulling the frames (when the water is flowing) against the current; this can be done easily because the water is then of equal height in front and behind.