Metal-Colouring and Bronzing

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: FUNDAMENTAL CHEMICAL RELATIONS 10. Before proceeding with the description of the production of the various colours produced on bodies by different bronzes, it will be necessary to give a general idea of the physical and chemical properties of the metals, and to explain the nature of chemical change which...
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: FUNDAMENTAL CHEMICAL RELATIONS 10. Before proceeding with the description of the production of the various colours produced on bodies by different bronzes, it will be necessary to give a general idea of the physical and chemical properties of the metals, and to explain the nature of chemical change which plays such an important part in bronzing. With about seventy exceptions all known substances, by various chemical processes, may be decomposed, and are therefore termed chemical compounds; while the seventy known bodies which have never been resolved into simpler parts are termed chemical elements. Of the latter more than three-fourths possess metallic properties, and are distinguished by the name of metals, in contradistinction to the remainder which are termed non-metals. The chemical elements possess almost every shade of physical character, and if we include the infinite variety of metals which can be produced by the process of alloying, the significance of this statement is still more marked. Among elementary substances we have oxygen, nitrogen, hydrogen, chlorine, and fluorine, which are gases under all ordinary conditions. Bromine and mercury are liquids. With regard to the solids it may be stated that some are readily volatile, such as iodine and arsenic, some easily fusible, such as phosphorus, and some which require thevery highest temperatures to effect their fusion, such as platinum. Hydrogen is the lightest and osmium the heaviest of all known bodies. Many elements occur in nature in the free state, such as oxygen, nitrogen, sulphur, gold, silver, copper, etc.; but by far the larger portion only exist in combination with other bodies, and those which occur in the free state, with three or four exceptions, only do so in comparatively small quantities. ...