Chap. VI.
FRANCE.
223
this was laid a second platform of timber of the same scantling, crossing the first, and securelypinned to it by barbed irons, 14 inches long and 1 inch square. These cross timbers wereplaced 21 inches apart, and the spaces filled up with brick laid in tarras, or mortar madeof lime and sand, with a proportion of one third of Dutch tarras. An oak floor, 3 inchesthick, was laid over the spaces between the intended walls, formed of planks, none of whichwere less than 20 feet in length, fastened by spikes, 7 or 8 inches in length, as well aswooden pins; after which the joints were caulked. In the passages was a range of longi-tudinal timbers, and three others under each of the three walls, care being taken that oneof these should be under the face of each wall : these longitudinal pieces were secured tothe cross timbers below them by barbed iron pins, 17 to 18 inches long, and 1^ inchessquare. Upon this third platform was another course of cross timbers, each in one length,placed immediately over those below : their length was only 4 feet more than the width ofthe passages. These cross timbers were united to the longitudinal ones below by similariron pins to those described, 18 inches in length. The spaces between were filled upwith brickwork to the level of the top, on which was laid a coat of mortar and a layer ofmoss over which was another floor of plank, 2 inches in thickness, but not extending beyondthe water-way.
As this work advanced, the main timbers for the pointing sills were laid down, and thetwo ends of the platform were secured by rows of sheet piling confined at the head bybinding pieces 12 inches square. The chief timbers under the pointing sills were 28 feet6 inches long, and nearly 2 feet square. Those of the smaller passage were of the samescantling, but less in length.
The sill which sustained the heel parts of the great gates was 28 feet long and 2 feetsquare. The pointing sills were 10 feet long and 24 inches square, all secured by ironpins.
The sill of the smaller passage was 23 feet long, and 2 feet by 1 foot 9 inches square;that of the turning gate w^s 25 feet 6 inches in length, and 2 feet square : to give it ad-ditional strength, two timbers of the same scantling were laid at right angles with it in themiddle of the water way. After the whole was carefully set out, and the site for the wallstraced, the masonry was commenced with stone from Landretun, which was laid in regularcourses 10 inches in height, and having their beds not less than 20 inches. These stoneswere cramped wherever there was any pressure, particularly where the turning gate wasplaced, and the reveal carried up to receive it. The walls were backed with brickworklaid in cement, to the thickness of from 2 to 3 feet, above which common mortar was used.The bricks were dipped in water previous to being laid.
The side and middle wall being carried up 4 feet above the level of the highest floodswere finished by a course of flat stones.
The turning gate was composed of two upright posts besides the middle, which had thepivot on which it turned. There was a bottom, a top rail, and two horizontal between,which were braced from the middle post; and at each mortice and tenon the joints weresecured by strong irons. The middle or turning post, 17 feet in height, and 18 inches by16 inches square, worked its gudgeon in a collar. The outer posts were 12 feet 9 inches inheight, 13 inches by 11 inches. The gate was 1 foot more in width than the water way,that it might rest securely agrinst the reveals prepared to receive it when closed.
One side of the turning gate was wider than the other, that the sea, at the time of flood,should have the power of shutting it: it was not quite at right angles, but presented aninclined face to the action of the water. A valet was contrived on the inside to keep thegate closed, and prevent the fresh water from running out of the canal at the time of lowwater. This valet or key to secure the gate was formed of a turning point, 11 feet inlength, and 12 by 7 inches, and a branch 15 feet in length of the same scantling, united bytwo ties framed into it and rendered secure by iron straps; when used, a rope or chainwas attached to the upper hook, which pulled it round on its pivot, and when broughtflat against the turning gate, it was secured to the middle post, and prevented the waterfrom the sea-side from forcing it open.
The Port of Cherbourg , in the department of La Manche , in 49° 38' north latitude, and1° 37' west longitude; it is situated on the most northern coast of the peninsula ofContentin in Normandy , and the bay between Cape de la Hogue and Barfleur, and has theform of a crescent. There are two harbours which communicate by means of gates, andat the entrance two piers have been carried out; that on the east side extends nearly halfa mile in length, and the other about half that distance, the width at the entrance being210 feet. The outer harbour is in length 360 yards, in width 250, and has a depth ofwater at low spring tides of 30 feet.
The quay, 200 feet in width, is built of stone, and extends in a straight line from Fort duHamet to Fort du Gallet: the inner basin is entered between two circular returns.
Napoleon expended vast sums of money in the construction of docks, slips, and quays,using the granite obtained from Barfleur.
This port is cleansed by sluicing, at the time the tide is low, or when there is not more than