320
EXPOSITION AT VIENNA.
to be strong. Some perforated curved bricks like the
figure, 16x4x2 inches, were also in the collection.
Curved channel tiles for open drains or gutters, by the same exhibitor, merit attention. These are
made in three parts, fitted together longi- tudinally, and are of several sizes, all of them with large openings in the body, effecting a great saving of material and giving lightness and strength.
Dovetailed Bricks.— France.
Mr. E. Pavy, of Chateau du Claveau, near Mezieres-en- Brenne (Indre), France, exhibited a novel invention, for which he has taken out a patent in France, consisting of bricks formed with dovetailed recesses in each end, so that two bricks may be locked together by a third piece which fits into the two opposite openings.
The dimensions of the ordinary bricks are stated as 0 m -25x0 m -12x0 m -06, which is about 9|x4|x2| inches. The locking-piece or dovetail is about five inches long.
The inventor claims for these bricks that they permit of the rapid construction of walls of a single course having not only lightness but great strength ; or of thick walls, of two courses of the brick, with an air-space between, giving greater strength than is obtained in ordinary constructions using two or three times as much material, and consequently requiring more carting, more time, labor and expense. The circular brick are designed for round towers and chimneys, and appear to be favored by the exhibitor as an attractive mode of finishing the corners of constructions, an ideal house being figured by him with a round tower at each corner.
Window frames of oak, or iron, are made with a dovetailed recess in the sides, into which the small locking-piece is fitted, thereby forming a tight joint and holding the