THE CLAYS OF WISCONSIN.

6 to 8 ft. of yellowish clay, mixed with pebbles and lime-
stone, all of which should be stripped.
10 ft. of shale. Does not stand much heat.
3 layers of limestone.
3 ft of shale. Shrinks more than other shale beds and
is used mainly in the manufacture of tile.
1 1-2 ft. of limestone.
15 ft. of shale. Shrinks very little in burning.
This plant is equipped with four machines, an Andrews
Dry press, a Wellington soft mud machine, and two, stiff
mud brick and tile machines, an intermediate Wonder and
a 9-A Brewer. The clay is weathered before using. For
the manufacture of soft mud brick the shale is ground be-
fore being transferred to the machine. For the manu-
facture of tile the clay is ordinarily screened after being
ground. The brick and tile are dried in a Wolff drier
which has a capacity of about 30,000 per day. The tile
are burned in a Eudaly down draft kiln and the brick are
-brned in permanent up draft kilns. About one-third of
a cord of wood is consumed for each thousand brick
burned.
The brick have a straw yellow color but owing to the
sand used in moulding they are usually finely speckled.
The brick do not melt around the arches and give evidence
of standing a moderate heat.

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