Trass, the local name of a volcanic tuff occurring in the Eifel, where it is worked for hydraulic mortar. It is a grey or creamcoloured fragmental rock, largely composed of pumiceous dust, and may be regarded as a trachytic tuff. It much resembles the Italian puzzolana and is applied to like purposes. Mixed with lime and sand, or with Portland cement, it is extensively employed for hydraulic work, especially in Holland; whilst the compact varieties have been used as a building material and as a fire-stone in ovens. Trass was formerly worked extensively in the Brohl valley and is now obtained from the valley of the Nette, near Andernach.
Trau (Serbo-Croatian Trogir; Lat. Tragurium), a seaport of Dalmatia, Austria. Pop. (1900) of town and commune, 17,064.17,064. Trail is situated 16 m. W. of Spalato by road, on an islet in the Trail channel, and is connected with the mainland and the adjoining island of Bua by two bridges. The city walls are intact on the north, where a 15th-century fort, the Castel Camerlengo, overlooks the sea. Above the main gateway the lion of St Mark is carved, and the general aspect of Trail is Venetian. Its streets, which are too narrow for wheeled traffic, contain many interesting churches and medieval houses, including the birthplace of the historian Giovanni Lucio (Lucius of Trail), author of De regno Dalmatiae et Croatiae (Amsterdam, 1666). The loggia, built by the Venetians, is a fine specimen of a 16th-century court of justice; and the cathedral is a basilica of rare beauty, founded in 1200 and completed about 1450. It was thus mainly built during the period of Hungarian supremacy; and, in consequence, its architecture shows clear signs of German influence. Among the treasures preserved in the sacristy are several interesting examples of ancient jewellers' work. Trail has some trade in wine and fruit. It is a steamship station, with an indifferent harbour.
Tragurium was probably colonized about 380 B.C. by Syracusan Greeks from Lissa, and its name is sometimes derived from Troghilon a place near Syracuse. Constantine Porphyrogenitus writing in the 10th century, regards it as a corruption of ayyvpiov, water melon, from a fancied similarity in shape. He states that Trail was one of the few Dalmatian cities which preserved its Roman character. In 998 it submitted to Venice; but in I r05 it acknowledged the supremacy of Hungary, while retaining its municipal freedom, and receiving, in 1108, a charter which is quoted by Lucio. After being plundered by the Saracens in 1123, it was ruled for brief periods by Byzantium, Hungary and Venice. In 1242 the Tatars pursued King Bela IV. of Hungary to Trail, but were unable to storm the island city. After 1420, when the sovereignty of Venice was finally established, Trail played no conspicuous part in Dalmatian history.
See T. G. Jackson, Dalmatia, the Quarnero, and Istria (Oxford, 1887); E. A. Freeman, Sketches from the Subject and Neighbour Lands of Venice (London, 1880; and G. Lucio, Memorie istoriche di Tragurio, ora detto Trail (Venice, 1673).
