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EXPOSITION AT VIENNA.
is alone used. This, I believe, is already known in America. Its essential features consist in the feeding of the fires from above, and in a strong draught produced by a tall chimney. It is said to occasion a great saving of fuel, estimated at as high a rate as three-quarters of that required for the old methods of burning ; but the bricks do not seem as hardly burned as our own. Among the conspicuous Austrian structures at the International Exhibition was a triumphal archway, erected of the products of this factory. Under its shelter were exposed various models of furnaces,—terra-cotta objects, such as vases, brackets, etc., of very exquisite design,—and many varieties of brick. The bricks used generally for building purposes in Vienna are slightly less than 12x6x3 inches, the full size being made up by the joints ; others are to be seen here eighteen inches and two feet in length, used, as previously described, for cornices, window-cappings, etc., in connection with mastic ; others used for similar purposes have one edge bevelled to avoid the necessity on the part of the workmen of chipping them with the trowel. In addition are hollow bricks used in the construction of fire-proof floors, firebricks, perhaps six inches square and two inches thick, used in paving cattle stalls ; wedge-shaped bricks for arches and vaults ; and hollow conical bricks, in shape much like a small flower-pot closed at both ends. Some of the latter have been employed in the construction of the dome which surmounts the centre of this triumphal arch. Nearly all of these varieties are, I believe, if not novel in America, still limited in their use there. While here upon the continent generally, and especialy in Austria, the arch and vault play a prominent part in every house, in America only our most important public buildings are constructed with them. In Vienna the law requires that the cellars shall be, with few exceptions, vaulted throughout, while in the basement story, the ceiling is in general supported upon iron girders or beams upon which are sprung vaults of hollow brick. These measures are taken in part to secure the solidity of the building and in part as a precaution against fire. A valuable and costly w r ork upon the subject of terra-cotta and form-bricks, containing numerous colored illustrations, by Gruner, appeared some years ago in London, and is recommended to all especially interested in the subject.