Gold parting of the salt cementation process. This mixture is then added to an earthenware pot and layered with thin sheets of gold fold. The pot is then sealed and heated in a furnace. It was during the medieval period that distillation was discovered and the first description of nitric acid production was given by Pseudo-Geber in the "Summa perfectionis", 1330. Nitric acid is able to dissolve silver. The addition of sal ammoniac to nitric acid creates Aqua regia and this acid is able to dissolve gold. Both acids are used in the acid method of parting but the acids were expensive
Acid perfusion test Acid perfusion test Acid perfusion test, also called the Bernstein test, is a test done to reproduce the pain when the lower esophagus is irrigated with an acid solution in people with GERD (gastroesophageal reflux disease). There will be a negative result in normal people, but a false positive reading may be seen in up to 15% of people. Bernstein test is obsolete nowadays. 24 hour pH monitoring is the gold standard for GERD. However, the initial management is with proton pump inhibitors. If the patient does not respond to it, and continues to have symptoms of GERD, i.e. heartburn,