Metallographia, or, An history of metals [electronic resource] : wherein is declared the signs of ores and minerals both before and after digging, the causes and manner of their generations ... with the description of sundry new metals ... : as also the handling and shewing of their vegetability, and the discussion of the most difficult questions belonging to mystical chymistry, as of the philosophers gold, their mercury, the liquor alkahest, auram potabile, and such like : gathered forth of the most approved authors that have written in Greek, Latine, or High-Dutch, with some observations and discoveries of the author himself / by John Webster ...