The red and black bodies made by Elers are still in fashion, but even more valuable than the doubtful invention of the particular ware was his careful method of refining and mixing the clay body, and the exact turning of the pieces to extreme thinness and precision of outline. On the excellence of his work, rather than on inventions which were not really new, his fame deserves to rest. He may not, for example, have been the first to introduce the method of sealing on the clay ornaments, but the ornaments themselves were for the first time in really good taste. It was this refined taste and precision of execution—and the proof that it paid financially—which taught the Staffordshire potters the most valuable lesson. Thus it was that, when Queen Anne and tea drinking came in, North Staffordshire had not only the clay and the coal, but also the tradesmen to make the ware required. CHAPTER IV. THE SALT-GLAZE POTTERS. The successors of Elers—Robert Astbury, Joshua Twyford, and especially Dr Thomas Wedgwood—built up the reputation of the salt-glazed stoneware, which for fifty years was the glory of North Staffordshire; and, in the improvements they effected, the first two atoned for anything that to the modern mind was irregular in the manner by which they got their start. It was to Dr Thomas Wedgwood (1655-1717), and his son Thomas (1695-1737), who made stoneware at “Ruffleys” in Burslem, that local tradition ascribes most of the improvements in salt-glazed wares. Mr Burton writes of the younger Dr Thomas: “It has never been suggested that Dr Thomas Wedgwood, like Twyford or Astbury, learned anything directly from Elers, but as he was a man of intelligence and commercial aptitude, as well as one of the best practical potters of the day, he would naturally adopt such new ideas as were brought in his way. Judging by the fragments of drab salt-glazed stonewares that have been found on the site of his old works in the centre of the town of Burslem, collectors are in the habit of attributing to him, with some show of justice, the finest pieces of this type.”[28][29] The secret of the salt-glaze process consists in firing the ware, specially composed of clay mixed with some siliceous sand or flint, to a temperature higher than ordinary earthenware will stand, and then, when red hot, shovelling common salt on to it through the top of the furnace. The salt fumes, passing through large holes in the saggars, cover the ware with a fine coat of colourless soda glaze. This glaze can always be distinguished from lead glazes by its peculiar pock-marked roughness, which indeed makes it somewhat unsuitable for plates or dishes for ordinary use; and, although for fifty years salt glaze did more than hold its own in public estimation, improvements in the old earthenware finally drove it out. By the end of the eighteenth century salt glazing had ceased to be practised.