text: From classical times through the 19th century, the main source of this substance in Europe wasAlmaden in Spain.
full_question: From classical times through the 19th century, the main source of this substance in Europe wasAlmaden in Spain. This substance is at the bottom of cells in which the Castner-Kellner process isperformed, in which it serves as a cathode. This substance was used along with saltwater in vats for the"patio process" to extract silver ores at sites in New Spain such as Potosi. A bond between it and sulfurexists in each molecule of the preservative (*) thimerosal, and it also exists bonded to sulfur in the ore cinnabar.Qin Shi Huangdi allegedly died by taking pills of this substance to extend his lifespan. For 10 points, name thismetal, the only one which is liquid at room temperature.
first_sentence: From classical times through the 19th century, the main source of this substance in Europe wasAlmaden in Spain.
raw_answer: mercury [or Hg; or quicksilver; prompt on amalgam]