PORT GLASGOW, a seaport, market-town, burgh of barony, and parliamentary burgh of Renfrewshire, Scot land, is situated on the south side of the Clyde, 2 j miles east of Greenock and 20 west of Glasgow. The elevated ridges to the back of the town are clothed with trees, their lower slopes being occupied with villas. The streets are wide, regular, and well-paved. The principal buildings are the court-house in the Grecian style, the town-hall, and the custom-house. On the adjoining slopes to the east are the picturesque ruins of Newark Castle, the ancient seat of the Maxwells. There are large and commodious harbours, a wet dock, and a graving dock. The port carries on an extensive trade with British North America, the United States, the Indies, and the Levant, the principal exports being iron, steel, machinery, and textile manufactures. The trade, though checked for a time by the rapid progress of Greenock, has been for some years on the increase. The shipbuilding-yards give employment to a large number of persons both in the town and the neighbouring burgh of Greenock. Connected with the shipbuilding industry there are manufactures of sail-cloth, ropes, anchors, and chain cables, also engineering and riveting works, and iron and brass foundries. The population of the police burgh in 1851 was 6986, which in 1871 had increased to 10,823, and in 1881 to 13,224. The population of the parliamentary burgh in 1881 was 10,802....