Nature's Miracles (volume 1); Familiar Talks On Science by Elisha GrayNature's Miracles (volume 1); Familiar Talks On Science by Elisha Gray

Nature's Miracles (volume 1); Familiar Talks On Science

byElisha Gray

Paperback | January 10, 2012

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This historic book may have numerous typos, missing text or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1899. Not illustrated. Excerpt: ... CHAPTER IV. SLATE AND SHALE. Slate is one of the great commercial products of the world. As far back as the year 1877 the output of slate was not less than 1,000,000 tons per annum. The chief use to which slate is put is for covering buildings, and for this purpose it is better than any other known material. It is also used in the construction of billiard tables and for writingslates; these latter uses are very insignificant as compared to its use in architecture. Slate, like building-stone and limestone, is quarried from the earth's crust and is found in the strata close above the Metamorphie rocks, near the beginning of what is called the Primary, or Paleozoic period. As compared with the coal formations it is very, very old. There are different substances called slate that are not slate in the scientific use of that word. In general all stone formations are called slates that split up into thin layers. But the true slate is a special material which is formed by special processes of nature. The difference between slate and shale, for instance, is not one of ingredients, but of the process by which the ingredients are put together. All of the sedimentary rocks are formed by a deposit of sediment from the water on the bottom of the ocean. At one period the floods have brought down a certain kind of material in greater profusion than at others, and this is deposited in thin layers, and as it hardens there will be seams in it and the stratifications will be differently colored, the color depending upon the deposit at any particular time. A bed of shale, like a bed of coal, has lines of cleavage in it, and if it is examined under a microscope it will be found that the sedimentary particles, like the twigs and leaves in the coal veins, lie with their longest dimensi...
Title:Nature's Miracles (volume 1); Familiar Talks On ScienceFormat:PaperbackDimensions:52 pages, 9.69 × 7.44 × 0.11 inPublished:January 10, 2012Publisher:General Books LLCLanguage:English

The following ISBNs are associated with this title:

ISBN - 10:021702498X

ISBN - 13:9780217024983

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