Minutes of Proceedings of the Institution of Civil Engineers Volume 94
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1888 edition. Excerpt: ...consist mainly of metallic oxides, notably oxide of iron; organic substances also affect the colour. A red colour in clay in its natural state indicates the presence of peroxide of iron. A yellowish or brown colour denotes the presence of hydrated peroxide of iron in the clay, which becoming anhydrous on burning imparts a red colour to the clay. The Dorset and Devonshire clays, being free from iron, are white when burnt, which renders them especially valuable for pottery. Clays containing manifest impurities to a considerable extent are designated by the terms shaly clay, sandy clay, loamy clay, and marly clay. Any soft admixture of clay and lime is termed a marl--clay-marl when the clay is in excess, and marl-clay when the lime predominates. Many clays are known by the name of the neighbourhood from which they are obtained, such as London clay, Oxford clay, Grinstead clay, Wadhurst clay, Weald clay, Kimmeridge clay, Gault clay, Poole clay, and others. Puddle is of considerable importance in engineering works for arresting the passage of water. Some clays, such as the London, Kimmeridge, and Oxford beds, are practically impervious to water in their natural condition; whilst others offer more or less resistance to its passage in proportion to the absence of impurities. Springs at faults or at the outcrop of clay-beds furnish evidence of the impermeability of these beds.. Most clays, when free from coarse gritty impurities, contain sufficient alumina to become practically impervious to water when worked up into puddle. When puddle is protected from evaporation, as is generally the case, the admixture of impurities has the disadvantage of diminishing its cohesiveness, and consequently its impermeability. If, however, puddle is placed so near...
- Paperback | 160 pages
- 189 x 246 x 9mm | 299g
- 13 Sep 2013
- Illustrations, black and white