Chap. VIII.

BRITAIN.

337

about 12, and at Newcastle 11 feet 6 inches. The velocity of the current of the flowingtides in springs al>ove Shields is about 3 knots an hour at half flood, but about half ebb itis increased half a knot.

Jarrai Slake , which is covered at half flood, contains nearly 350 acres.

Berwick-upon-Tweed , is on the left bank of the river, and has a pier, erected under thedirection of the late Mr. Rennie, at the end of which is a lighthouse. The harbour is byno means a convenient one; and the river, which is here crossed by a bridge of fifteenarches, is the second in point of importance to any in Scotland .

Fig. 333.

BERWICK-UPON-TWEED.

Here, originally, was a pier, constructed in the reign of Elizabeth, which afforded shelterfrom storms from the north-easterly wind. Spring tides rise here about 15 feet, and neapsabout 9 feet; and at high water of an ordinary spring tide, there is 19 or 20 feet water onthe bar, and from 14 to 15 feet at the quay; at neap tides there is not so much by 3 or 4feet.

Eyemouth Harbour , is advantageously situated at the corner of a bay, where ships canwork in and out at all times of the tide, and lie at anchor secure from all winds, except thenortherly or north-easterly.

Mr. John Smeaton , in the year 1767, who was consulted upon the best means of im-proving it, found that the mouth of the river being open to northerly winds, the vesselscould not lie secure without going beyond the elbow of the quay, where there was but veryshallow water, and the breadth was much contracted. At a full sea, the mouth of theharbour being wide admitted the waters with so much impetuosity, that they found theirway round the elbow and disturbed the quiet of the vessels which took shelter there. Toenlarge the harbour, and to increase its security, he advised the construction of a northpier to defend the mouth, and which was to be based upon a natural ledge of rocks.

The entrance to the harbour was at right angles with the direction into and out of thebay ; and at spring tides there was 20 feet of water; and between the pier heads, therewas several feet at low water, at the lowest ebbs; and at neap tides it was calculatedthere never would be less than 16 or 17 feet in the harbour, which would be capable ofreceiving vessels of from 300 to 400 tons burthen.

The length of the pier from the elbow and round the head into the flank was to be 240feet, its mean height 22 feet, and the mean thickness of the two walls 5 feet. The lengthwithin, from the elbow to the said flank, was 132 feet, and the mean thickness of the walls3 feet. The width of the base was 30 feet, and as the casing walls were built with falling-in faces, the interior was filled in with rough stones placed by hand, and well packed. Thefaces of the wall and parapets only were built in regular courses of freestone, which werelaid in mortar, hammer-jointed and faced.

Dunbar Harbour , though situated advantageously at the bottom of a bay, was withdifficulty to be entered, as the passage for vessels was extremely narrow ; and the slopingof the rocks on the starboard or north-west side, going in, contributed to increase the evil,for vessels being obliged to keep close to the pier were often driven on it by the recoil ofthe sea from the rocks. John Smeaton , in 1772, to remedy this inconvenience, recom-mended that the rocks should be sloped oft’, level with the bottom of the rest of the pas-

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