The success of Minton in majolica, tiles and porcelain led the Wedgwoods at Etruria to depart so far from their special black basalt and jasper as to take up similar lines of manufacture. Their brown majolica glaze, known as “rockingham,” perhaps the most permanently successful form of majolica, was introduced about 1860.[201] (This “rockingham” glaze had been first employed about 1796 near Rotherham on the Marquis of Rockingham’s estate in Yorkshire.)[202] Then, in 1872, they began again to make porcelain, and this time with great success. A Wedgwood china dinner service of 1296 pieces was selected by President Roosevelt for the White House in open competition with the whole world. From 1880 till 1902 Wedgwoods also made encaustic and white-glazed tiles, though without any financial success. This firm now employs about 700 people, and is carried on by Messrs Lawrence, Cecil and Francis Hamilton Wedgwood, the great-grandson and great-great-grandsons of Josiah Wedgwood, making altogether eight generations of master-potters from father to son, probably a unique example in any industry. While Mintons, Copelands and Wedgwoods were producing the most costly porcelain, the trade in the commoner china had centred more and more at the Longton end of the Potteries. Charles J. Mason with his “ironstone china” at Fenton between 1820 and 1850 was the precursor of this trade, and it was on this export trade that Longton grew so rapidly throughout the 19th century. The manufacture of cheap “jet” and “rockingham” has become of recent years an important branch of manufacture at this Longton end, and very opportunely, for the cheap china trade has suffered more than any other from the German and Dutch competition. Messrs Wileman’s factory at the Foley, now owned by Mr Percy Shelley, is the most important, but the Longton china trade generally is in the hands of small men. A great part of this china trade was formerly with America, and, apart from ornamental potting, it has always been the solid American trade which has made the fortunes of the Staffordshire potters. In the forties the chief exporters of earthenware to America were Enoch Wood of Fountain Place, and Samuel Alcock of the Hill Top Works, both in Burslem. Samuel Alcock had several factories in Burslem, and deserves mention for his “Parian” figures, but his great trade was in plain white and cream colour with the United States.[203] Alcock’s old Hill Top Works, where John Mitchell once used to entertain Wesley, belong now to Samuel Johnson, noted for his tea-pots.