Page:Popular Science Monthly Volume 40.djvu/312

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298
THE POPULAR SCIENCE MONTHLY.

acres and including thirty-five ware and decorating kilns. The business was started in 1854 by Mr, Isaac W. Knowles and Mr. Isaac A. Harvey, who, with a single kiln, made yellow ware and, later, Rockingham, In 1870 Mr. Knowles, who had purchased the interest of his former partner, was joined by Messrs. John N. Taylor and Homer S. Knowles, and in 187:3 they commenced the manufacture of iron-stone china and white granite ware. The business of the company has had a phenomenal growth, and at the present time they employ about seven hundred hands in the production of extensive lines of white granite and vitreous hotel china, which they supply to the trade.

The Faience Manufacturing Company, of Greenpoint, Long Island, produces white ware artistically decorated and, we believe, a limited quantity of porcelain. The pieces are of ornamental rather than of useful shapes. The engraving (Fig. 26) represents a ewer vase from this factory with open-work handle and molded figure of bird. It is unfortunate that the secrets of this factory should be guarded so jealously as to deprive us of all knowledge concerning the processes employed and the qualities of the wares produced. Repeated inquiries have failed to elicit any reply.

To Mr. Thomas C. Smith, of Greenpoint, Long Island, belongs the honor of being the first American manufacturer who has been successful in placing upon the market a true hard porcelain as a commercial article. His experiments, which extended over a number of years, first commenced to bear fruit about 1865, when he perfected a plain white ware, and a year afterward he commenced to decorate his goods. The Union Porcelain Works, of which Messrs. Thomas C. Smith and C. H. L. Smith are the proprietors, have produced many decorative pieces in addition to their staple productions of true porcelain table ware.

This porcelain is composed in body of clay, quartz, and feldspar. It is fired in biscuit at a low temperature, in the second story of the porcelain kiln, using for its baking the surplus heat passing away after having done its greater work in the first story or gloss-kiln where the glazing is done. At this first burning the ware receives only sufficient fire to make it properly fasten together in form. It is quite fragile, easily broken with the fingers, and porous, not having yet had sufficient heat to commence vitrification. In this condition it is what is termed porcelain biscuit, and is ready for the glaze-tub. The glaze of porcelain is composed of the same material as the body, and so compounded that those elements which are soonest fluxed by the influence of the heat are in greater proportion than they are contained in the body. The porous, low-fired biscuit is dipped into a liquid puddle of glaze. Upon being withdrawn its porosity quickly absorbs the excess of water, leaving a dry coating of the glaze compound,