David Thomas was born in Cadoxton, near Neath, in 1794. He was the only son of David and Jane Thomas, who gained a poor livelihood at farming. Both parents were deeply religious, belonging to the "Independent" community at Maesyrhaf Chapel, and they gave David strict training.
He attended school first at Alltwen, but his progress was so rapid that he was sent to a more advanced school at Neath at the age of nine.
Beginning in 1812, he was employed at the Neath Abbey iron works, where he acquired a thorough knowledge of blast furnaces as well as technical training in building mining machinery and Cornish pumping engines. After five years here he was made general superintendent of the Yniscedwyn Iron Works, which three years later was acquired by George Crane. This plant was erected on the only bed of anthracite coal in Great Britain, but no method had yet been devised to use this fuel in the smelting of iron ore.
For years both Crane and Thomas tried to utilize the anthracite without success, two expensive experiments terminating in absolute failure. In 1836, however, their opportunity came when they read about the hotblast invention of James Beaumont Neilson. As a result Thomas went to Scotland, where the hot-blast method was already being employed, and returned with permission to use this patented process. Work was started immediately on the construction of a furnace and it was blown in February 1837 with such successful results that world-wide attention was at once focused upon the plant.
Within a short time the Lehigh Coal & Navigation Company of Pennsylvania reached an agreement with Crane and Thomas by which the latter signed a generous contract to construct and operate similar furnaces on the Lehigh River, the plant to be called the Lehigh Crane Iron Company. Thomas was hesitant about going to the United States, but his ambitious wife urged him to accept the position. In May 1839, after he had spent four months in purchasing machinery, he set sail with his family from Swansea to Liverpool and thence to New York. They arrived in Allentown, Pa. , July 9, 1839. Construction of the blast furnace was begun almost immediately and was carried to completion in the face of great odds. It was necessary to have the blowing cylinders built in the United States, and none of the few foundries in existence had ever made machinery of such large size.
Thomas suffered a severe illness in the autumn of 1839 which prevented him for a time from overseeing the actual construction. He found it hard to secure experienced labor, and the ores and fuels with which he was supplied were of unknown and varying constituents. Nevertheless, his indomitable energy, activity, courage, and tenacity enabled him to overcome all these difficulties and on July 4, 1840, the first furnace of the Lehigh Crane Iron Company produced four tons of good foundry anthracite iron.
Small amounts of anthracite iron had been manufactured a year or two earlier, but Thomas' Catasauqua furnace was the first of all the early anthracite-iron manufacturing establishments to be permanently successful from both the engineering and the commercial standpoint. For this reason and because he subsequently became identified with the manufacture of anthracite pigiron on a more extensive scale than any of his contemporaries, he has been justly called "the father of the American anthracite-iron industry. " While Thomas did not develop any new basic principles in the smelting of iron ore, he was directly responsible for many improvements, among which were the erection of higher and larger furnaces and better and more powerful blast machinery, and the use of steam instead of air for making the blast.
In 1854, he and several others organized the Thomas Iron Company at Hokendauqua, Pa. Although he did not take an active part in the management of this enterprise for several years, because he maintained his connection with the Lehigh Crane Company, he took an active interest in its affairs even to the extent of indorsing and filing a personal bond guaranteeing the money borrowed by the Company during the financial panic of 1857. He was principally interested in other manufactories, including the Lehigh Fire-Brick Company and the Catasauqua Manufacturing Company, and for a great part of his declining years was president of the latter concern.
He took much interest in the political, financial, religious, and charitable affairs of Catasauqua, where he lived until his death. He was president of the Catasauqua & Fogelsville Railroad and a director of the Lehigh Valley Railroad Company. He was elected first president of the American Institute of Mining Engineers because it was felt that he was "the man whose name would do more than any other name to unite in support of our new enterprise the enthusiasm of science with the experience of practice".
Thomas' wife was Elizabeth, daughter of John Hopkins, a native of Gilvendre, South Wales. Five children were born of this union; the three sons all became connected with the iron industry.
