Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . GLASS, MANUFACTURE OF. 47 in working and stirring the material while in a state of fusion, by means of a tool made of the samematerial as the crucible or glass-pot. He made a hollow cylinder of fire-clay of the same height asthe crucible, closed at its lower extremity and open above, with a flat ledge all round of severalcentimetres in width. Having heated this cylinder red-hot, he placed it in the melted glass; then,by means of a long bar of iron, bent to a right angle at a distance o
Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . GLASS, MANUFACTURE OF. 47 in working and stirring the material while in a state of fusion, by means of a tool made of the samematerial as the crucible or glass-pot. He made a hollow cylinder of fire-clay of the same height asthe crucible, closed at its lower extremity and open above, with a flat ledge all round of severalcentimetres in width. Having heated this cylinder red-hot, he placed it in the melted glass; then,by means of a long bar of iron, bent to a right angle at a distance of some centimetres from itsextremity, which he introduced into the cylinder of fire-clay, he worked and stirred the glass, by. giving the bar a horizontal rotary motion. For the manufacture of flint-glass, and of crown-glass,he adopted a circular furnace, in the centre of which is placed the crucible or glass-pot, all the partsof which are exposed to the same temperature; and covered crucibles are adopted, because withcrucibles of this form there is no danger of the glass being spoiled by particles of the fuel, or bydrops or tears from the crown or arch of the furnace. For the construction of this, sec Furnaces,Glass. Flint-glass, of the usual density, similar to that used for table-sets, decanters, etc., is composed,ordinarily, of 300 parts of sand, 200 of deutoxide of lead, and 100 of subcarbonate of potash. Thedensity of this flint-glass is from to The following composition, expressed in kilogrammes,gives the quantity necessary to fill the crucible: sand, 100 kilogrammes; deutoxide of lead, 100kilogrammes ; subcarbonate of potash, 30 kilogrammes. This composition gives a very white flint-glass, of
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Keywords: ., bookauthorbenjaminpark18491922, bookcentury1800, bookdecade1880
