f a work entitled _The Locomotive Engine_ (1851).

COLBY, THOMAS FREDERICK (1784-1852), British major-general and director
of ordnance survey, was born at St Margaret's, Rochester, on the 1st of
September 1784, a member of a South Wales family. Entering the Royal
Engineers he began in 1802 a life-long connexion with the Ordnance
Survey department. His most important work was the survey of Ireland.
This he planned in 1824, and was engaged upon it until 1846. The last
sheets of this survey were almost ready for issue in that year when he
reached the rank of major-general, and according to the rules of the
service had to vacate his survey appointment. He was the inventor of the
compensation bar, an apparatus used in base-measurements. He died at New
Brighton on the 9th of October 1852.

COLCHAGUA, a province of central Chile, bounded N. by Santiago and
O'Higgins, E. by Argentina, S. by Curico, and W. by the Pacific. Its
area is officially estimated at 3856 sq. m.; pop. (1895) 157,566.
Extending across the great central valley of Chile, the province has a
considerable area devoted to agriculture, but much attention is given to
cattle and mining. Its principal river is the Rapel, sometimes
considered as the southern limit of the Inca empire. Its greatest
tributary is the Cachapoal, in the valley of which, among the Andean
foothills, are the popular thermal mineral baths of Cauquenes, 2306 ft.
above sea-level. The state central railway from Santiago to Puerto Montt
crosses the province and has two branches within its borders, one from
Rengo to Peumo, and one from San Fernando via Palmilla to Pichilemu on
the coast. The principal towns are the capital, San Fernando, Rengo and
Palmilla. San Fernando is one of the several towns founded in 1742 by
the governor-general Jose de Manso, and had a population of 7447 in
1895. Rengo is an active commercial town and had a population of 6463 in
1895.

COLCHESTER, CHARLES ABBOT, 1ST BARON (1757-1829), born at Abingdon, was
the son of Dr John Abbot, rector of All Saints, Colchester, and, by his
mother's second marriage, half-brother of the famous Jeremy Bentham.
From Westminster school Charles Abbot passed to Christ Church, Oxford,
at which he gained the chancellor's medal for Latin verse as well as the
Vinerian scholarship. In 1795, after having practised twelve years as a
barrister, and published a treatise proposing the incorporation of the
judicial system of Wales wi