TERRA-COTTA, BRICK, ETC.
339
He observes that the clay pits about South Amboy furnish a large amount of this useful substance every year, and that the market is continually widening. It sold for from $1.50 to $5.00 per ton. Any needed amount of clay can be had from the pits along the Delaware and its branches. Clay suitable for making water-pipes is dug near the Woodmansie Station on the Raritan and Delaware Bay Railway. Light colored clays of the tertiary formation are found at many points in the southern part of the State, suitable for making a common quality of fire-brick and for other purposes.
Coarse clays, superior to brick clays, occur in inexhaustible quantities over and under the fire-clays. They are well adapted to the manufacture of coarse pottery, sewer-pipes, drain-tiles, etc., for which they are already, to some extent, utilized.
For the manufacture of glass-pots, which require a peculiar and excellent quality of clay, it was formerly thought that none of a suitable composition existed in the United States, and that only English and German clays could be relied upon. Experiments were made at Wheeling, Virginia, on clays obtained at the Mt. Savage Iron Works, and the measure of success attained encouraged the belief that the glass-works might become independent of foreign sources for this material. Soon after, a clay was obtained from Missouri which proved to be equal to, if not superior, to any other known clays for such purposes.
The fire-clays of St. Louis, according to Dr. Litton, have the following composition :—
Silica,
Alumina,
Oxide of iron,
Lime,
Magnesia,
Potash,
Soda,
Sulphur, .
W ater,
1 .»
2.t
61.02
59.60
25.64
26.41
1.70
1.61
.70
1.00
.08
.07
.48
.29
.25
.16
.45
.38
10.00
10.36
Raw clay.
t Prepared, probably washed.