BREAKWATER

An artificial bank of stones, or the hull of a ve el, sunk to break the sea before its entrance into a roadstead or harbour. The breakwater at Plymouth is a great work of this kind. It is built acro the sound, which it completely defends from a very heavy sea from the channel in south-westerly winds, and which formerly caused the lo of many ships. It is composed of large stones dropt from ve els constructed for the purpose. The sea, which for a time offers serious obstacles to the construction, works the stones together, and washes up shingle and sand, which, with the growth of sea-weed, consolidate the whole. The outer mole of the harbour of Civita Vecchia, still in good repair, was formed by the Emperor Trajan exactly in the same way as the breakwater at Plymouth. (Plinii Epist. lib. vi. ep. 31.) The breakwater at Cherbourg, constructed by Napoleon, is one of the greatest modern works of this cla . [s. 179]