Page:Miscellaneous Papers on Mechanical Subjects.djvu/148

 through the bars, while the large stones pass out at the lowest end.

The clay is next raised by elevators, which are fixed to an endless leather belt about a foot wide, to the height of about 12 feet, and conveyed to rollers. It is ground and shovelled into hoppers which feed the moulds; these are 8 inches long, 4 inches wide, and 4 inches deep.

The clay is dropped into the moulds, which are placed six in a row, to the depth of 3 to 3½ inches, according to the quantity of moisture it contains, and is afterwards compressed to the thickness of 2 inches in the following way:—

Six presses or rams, fixed in a heavy frame, are raised by a cam, and being allowed to fall, exert very great pressure by their impact on the clay. The blow is repeated, and then the bricks are powerfully compressed above and below by revolving cams; thirty-six bricks are made per minute. They are at once convened to the kiln, which is under the shed at a short distance from the machine.

After being burnt, they are separated into three shades of colour, of light and deeper reds. The best burnt bricks are equal in quality to the best English stocks, and were selling at $12 per 1,000.

41. Brickmaking from Dry Clay—(con - tinued).''—In