232
EXPOSITION AT VIENNA.
The earthy group includes faience, terra-cotta, bricks, etc. Faience is also a comprehensive term, taking in all varieties of earthenware stoneware, etc., and comprises two chief classes, the glazed and the unglazed. The objects may also • be grouped as hard faience, and soft faience, stoneware being an example of the former; but the classification according to the glaze, or superficial coating, is to be preferred. Of glazes, which consist of a composition much more fusible than the body of the ware, there are many varieties. All, however, have this in common, that they may become more or less fluid in the furnace, and cover the porous surface of the paste or body, giving a vitreous surface when cold. They are all more or less siliceous, but the substance giving the fusibility may be an alkali, or metallic oxide, usually oxide of lead, or of zinc, or oxide of tin. The alkalies and lead give a transparent glaze, and oxide of tin gives an opaque glaze or enamel, and objects covered with it are described as enamelled. A common and cheap method of glazing hard faience is by throwing salt into the kiln while the objects are‘hot. The soda combines with the silica in the ware, and a vitreous glaze, known as salt-glaze, results.
For this Report an arbitrary grouping is preferred, chiefly with a view to convenience of description. The objects are grouped according to their uses rather than by their material or manufacture. The faience and porcelains of the principal countries are first considered; next, the mural and floor tiles, as a distinct and largely represented branch of ceramic industry; third, terra-cotta, bricks, etc.; and-fourth, the materials used and their distribution. In each of these divisions there was a profuse representation in the Exposition ; and a thorough, critical, and explanatory description would have required much more space and time than have been at command. In general, only the salient feafures are touched upon. The writer has, as far as possible, brought prominently forward the names of the principal exhibitors, recognizing in this the discharge of a duty to them as well as to the public. Every exhibitor at a great exhibition, who makes a display worthy of the occasion, does so at no small outlay of time and mofiey, and he is justly entitled to all of the advantages