Page:Miscellaneous Papers on Mechanical Subjects.djvu/149

 tinued).—In a brickyard at Washington, Sawyer's machine, which had been in use for sixteen years, makes about 1,800 bricks per hour from dry clay by compression only.

The clay is obtained from a pit close by. As it is dug out it is carted up an inclined plane to the floor, over the room where the machinery is at work.

A roller weighing 1,600 lbs., and making sixty revolutions per minute, grinds it upon a grating through which the pulverized particles fall into the room below.

There it is shovelled into a hopper which supplies the brick moulds by feed-pipes. Three bricks are made at one time, being compressed by top and bottom pistons or pressers, which are connected together by long iron rods, and from the top part are suspended levers, with toggle joints worked by cranks. The bricks were sold at the rate of $6½ dollars per 1,000, and were of a medium quality between English seconds and stock bricks.