Memoir of the Geological Survey of the State of Delaware; Including the Application of the Geological Observations to Agriculture - Softcover
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1841. Excerpt: ... the last named substance is essential, as it acts by cementing the clay and sand or alumina and silica. Hence the white clay, containing but little oxide of iron, can never form a strong brick, while the yellow alone containing too much ferruginous matter, is apt to enter into semi-fusion and become glazed. These effects can be ascertained practically by the ring of a brick; for if it produces very little sound on being struck, it is either not burned sufficiently or there is too little iron in its composition; if it produces a very sharp and quick tone, it is burned too much or there is an excess of oxide of iron in the clay. It follows from what has been said that the excess or deficiency of iron may be remedied by adding more white or yellow clay. Where the two clays are not found in juxtaposition or conveniently near together, if we have white or lead colored, a yellow loam is added; if a yellow clay alone, we add sand and use a less intense heat in the kiln. It is frequently advisable to try the mixtures on a small scale, preparatory to burning a kiln, on a smith's hearth or other convenient place, for even those skilled in the art cannot always judge of the fitness of a clay by its external characters. Of the geological formations many have been and are employed in this manufacture; the red clay of New Castle county, §§ 47, 52, and the yellow clay of Appoquinimink hundred, §§ SO, 81, the intermediate clays of Kent, §§ 87, 88, the lower clays of Sussex, §§ 89, 94, as at Causey's, § 89, and Parker's, § 90, the more recent argillaceous deposites near tide-water throughout the state, the clay of the ridge, as at Georgetown in Sussex, and numerous local clayey beds or loams scattered through the three cou...
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