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Various substances, conventionally distinguished as simple, have several forms under which they present quite different properties. The semi-transparent, colourless, extremely active substance called phosphorus may be so changed as to become opaque, dark red, and inert. Like changes are known to occur in some gaseous, non-metallic elements, as oxygen; and also in metallic elements, as antimony.
Now vessels of glass, of porcelain, and of all non-metallic substances, are destroyed by the means we employ for that purpose, are acted upon by many acids, by alkalies and the alkaline carbonates. Crucibles of gold and silver would melt at high temperatures. But we have a combination of all the qualities we can desire in Platinum.
Even non-metallic surfaces could be reproduced in copper by taking a cast of them in wax and lining the mould with fine plumbago, which, being a conductor, served as a cathode to receive the layer of metal. It is by the process of electrotyping or galvano- plastics that the copper faces for printing woodcuts are prepared, and copies made of seals or medals.
Now, analysis has reduced all the products of this nature to four simple substances, namely: three gases, nitrogen, hydrogen, and oxygen, and another simple substance, non-metallic and solid, carbon. Is it probable that means should be more numerous where a lesser number of results are produced?
Other matters of serious moment in the electro-zincing process, apart from the slowness of the operation, were the uncertain nature, thickness, and extent of the coating on articles of irregular shape, and the formation of loose, dark-coloured patches on the work; the unhealthy and non-metallic look and want of brilliancy and the lustre prevented engineers and the trade from accepting the process or its results, except for the commoner articles of use.
Carbon was the first non-metallic element discovered in the sun. Messrs. Trowbridge and Hutchins of Harvard College concluded in 1887, on the ground of certain spectral coincidences, that this protean substance is vaporised in the solar atmosphere at a temperature approximately that of the voltaic arc.
The second is that since the envelope of the supposed spheroid would consist of the gases and non-metallic elements, compounds of these with the metals and with one another would continually accumulate on the molten shell; and the crust, consisting of oxides, chlorides, sulphurets, and the rest, having much less specific gravity than the molten shell, would be readily supported by it.
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