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EXPOSITION AT VIENNA.
is safe to burn them, but the machine-made bricks, it is claimed, do not contain more than one-eight this amount of water. This permits expensive sheds and drying floors to be discarded, and renders it possible to manufacture continuously throughout the year.
In Chicago, in 1872, there were some 400,000,000 of bricks made and used, and about half that number in 1873. The clay for the common brick is obtained from the excavations made for docks and slips along the river in the city. Fine front or facing bricks are made from clay procured at Gregg Station, eighteen nffles from the city, on the Chicago, Burlington and Quincy Railroad. Brick made from this clay in the Excelsior Press are surpassed in color only by the finer grades of Philadelphia and St. Louis brick, but are as strong as any.
Chambers’ Continuous Delivery Machine.— There were brick-making machines exhibited, belonging to the class of tempered clay continuous delivery machines, in which the clay, being properly mixed, is forced through a rectangular die in a continuous stream or column of clay, of the breadth and thickness required for brick. From this column of clay, bricks are cut olf at proper intervals, by wires, stretched in a frame, or by knives. The principle is the same as that of the machine invented and patented in the United States, by Cyrus Chambers, Jr., of Philadelphia. These machines have been in operation for several years, and have produced many millions of brick.
The machine is constructed almost wholly of irou, and is made very strong. It receives the clay direct from the bank, tempers it with water, and forms it into bricks, with well- defined corners, and smooth, straight surfaces, at the rate of from fifty to eighty per minute, or from twenty-five to thirty- five thousand per day for ten hours.
The tempering portion of the machine consists of a strong iron case, in which revolves a horizontal shaft, into which are set spirally, strong tempering knives, or blades of steel, so that, as they pass through the clay, they move it forward their thickness, or whatever distance they may be set to do. The clay being stiff, and not having much water on it, is not