Engineering Wonders of the World
Volume I

176 ENGINEERING WONDERS OF THE WORLD. MAP OF TILBURY DOCKS, SHOWING WET DOCKS, LOCK ENTRANCE, DRY DOCKS, AND TIDAL BASIN. diamond shape to the Empress, an open basin or tidal dock, with plenty of deep water both in it and around it. The case of Southampton is, however, exceptional. To enable Atlantic liners to embark and land their passengers and baggage at Liverpool at any state of the tide a landing stage, 2,063 feet long and 80 feet broad, has had to be provided. This rests on floating pontoons, and is connected with the land by means of half-a-dozen bridges. The stage rises and falls with the tide. An essential to the effective use of docks is, of course, a suitable approach. The channel leading into a port must be adequately pro- tected from the sea. The breakwater at Mar- seilles represents one kind of provision. But as the majority of ports have natural protec- tion, the chief trouble is to make and maintain adequately wide and deep and straight ap- proach channels. The Clyde has had to be deepened at enormous cost in order to main- tain the accessibility of Glasgow from the sea. Manchester has had to spend many millions on a canal. Liverpool, although distant but a MAP OF SOME OF THE LIVERPOOL DOCKS. and the Huskisson at Liverpool, and the Prince’s at Glasgow. At Marseilles there are jetties carried right out from the shore, and protected from the sea by a breakwater. At Southamp- ton the object is achieved partly by giving a mile or two from open water, has to keep some of the most powerful dredgers in the world continually employed sucking sand from the Mersey Bar. On the Thames dredging is nearly always going on with the object of keeping the