Thames (Temz), the most important river of Great Britain, flows ESE. across the S. portion of the country. Its four head-streams - the Thames or Isis, Churn, Coln, and Leach - rise on the south-east slope of the Cotswold Hills, the upper part of the main stream being often called Isis (a quasi-classical form of Ouse) and not Thames until after it receives the Thame near Dorchester. The Thames or Isis flows ENE. for about 35 miles, when, curving SE., it passes Oxford, and flows on to Reading. Here, after receiving the Kennet from the west, it again changes its course, and, winding eastward, passes Windsor, Eton, Ted-dington (the lowest of thirty-three locks between here and Oxford, and the highest point to which the tide ascends), Richmond, London, Greenwich, Woolwich, and Gravesend, below which it expands into a wide estuary, and enters the North Sea. On its tidal estuary, and on the fact that like most British rivers it has no delta, depends the river's importance as a navigable waterway; the navigation is, however, somewhat impeded by a ' submarine delta ' - banks formed of river sediment. From Lechlade to the Nore the direct length is 120 miles, and with the windings may be 250 miles (112 from Oxford to London Bridge); the area of its basin is 6100 sq. m. Its chief affluents are the Windrush, Cherwell, Thame, Colne, Lea, and Roding, on the left; and the Kennet, Lodden, Darent, Mole, Wandle, and Medway, on the right bank. At London Bridge its width is about 290 yards; at Woolwich, 490; at Gravesend Pier, 800; 3 miles below Gravesend, 1290; and at its mouth, between Whitstable and Foulness Point, about 8 miles below the Nore, it is 18 miles across. At the Nore Light, reputed the mouth of the Thames, the breadth is nearly 6 miles. The river is navigable for barges to Lechlade, and it is connected with several important canals. Vessels of 800 tons can reach St Katharine's Docks; much larger ones can ascend to Blackwall, 6 miles below London Bridge; and the largest sea-going steamers reach Tilbury Docks, 26 miles below. The part of the river immediately below London Bridge is called the Pool; and the part between the Bridge and Blackwall is called the Port. Two embankments have been formed, one since 1864 on the north shore from Blackfriars Bridge to Westminster, and one since 1866 on the south shore from Westminster Bridge to Vauxhall. The river supplies London with much of its drinking-water, and carries most of its sewage to the sea. Though the lower Thames has been converted into a sewer, in virtue of this same part of its course the river ranks as the chief commercial highway of the world. Above London the scenery is rich and beautiful, though not romantic, the numerous eyots or islands lending a peculiar charm. The Thames is the best beloved of English rivers for those who boat for pleasure. For boat-racing, it divides the honours with the Tyne; the Thames watermen are renowned in song and story. Since Spenser's days ' the silver-streaming Thames' has been sung by England's poets; Herrick calls it 'silver-footed Thamesis;' Denham's apostrophe is famous; and Pope has word-painted much of the scenery of its banks. It was (now alas ! long since) famous for its salmon, as it still is for other anglers' fish; below London flounders and eels are still plentiful, while the whitebait is almost peculiar to the lower Thames.

See works by Mr and Mrs S. C. Hall (1859; new ed. 1878), Robertson (1874), Huxley (1877), Farren (1881), Law (1881), George D. Leslie, R.A. (1881; new ed. 1888), Church (1885), Herring (1885), Cassell (Royal River, 1886), W. Black (Strange Adventures of a Hovse-boat, 1888), Justin M'Carthy and Mrs Campbell Praed (1890), Senior (1890), Mr and Mrs Pennell (1891), Wyllie and Allen (1894), Charles Dickens, junior (1880), and Sir Walter Besant (1903).