 ... lay fragments of sulphur in it, according to the quantity of the scraping, and carefully stir it with a thin piece of charcoal until its fumes cease; and immediately pour it into an iron mould. Then gently beat it upon the anvil, lest by chance some...  Diversarum artium schedula - Pàgina 319per Theophilus (Presbyter) - 1847 - 447 pàginesVisualització completa - Sobre aquest llibre
 | John Percy - 1880 - 758 pàgines
...gently beat it upon the anvil, lest by chance some of that black may fly from it which the sulphur has burnt, because it is itself silver. For the sulphur...will carefully keep. Again melt this gold in the same vessel as before, and add sulphur. This being stirred and poured out, break what has become black and... | |
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