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Pitch for bond:

BRIQUETTING WITHOUT BOND.

As has already been stated, there are two entirely different methods in use for the manufacture of artificial fuel from brown coal without the use of a bond. The fuel produced by these is known respectively as nass-press-kohlen, or water-pressed coal, and darr-press-kohlen, or briquettes.

WET PRESSING.

The simplest of these is the manufacture of nass-press-kohlen, but the fuel produced, though more stable than the earthy brown coal of which it is made, is suitable principally for domestic purposes. The coal used in this is the earthy brown coal containing a variable amount of "schweelkohle." The presses are run only during the warmer months, as freezing would destroy the briquettes. The mining of the coal is continued through the winter, however, and the great piles of coal are kept wet to prevent spontaneous combustion. The coal is thoroughly mixed and carried, by either inclined plane or aerial cable conveyance, to the room above the press. Here it is again wetted and mixed, and passes into the hopper between two heavy rollers, which reduce it to fine powder.

The press, which is very similar to a brick machine in character and operation, is illustrated in Plate XVIII.

It has a compressive force equal to five atmospheres.

The bricks are cut as the moulded block comes from the press, and then arranged on shelves in long open sheds, where they remain until they are dry, which takes from four to five days to as many weeks. When they first come from the press the bricks have the following dimensions:

65x118x200 mm.; 2½x4¾x8 inches.
In drying they shrink to the following:
60x115x190 mm.; 2¼x4½x7½ inches.

Their weight, which is in the freshly formed bricks about five pounds, is reduced by drying fully one-half, so they do not exceed two and a half pounds each.