Period 6 element also dissolves in alkaline solutions of cyanide, which have been used in mining. Gold dissolves in mercury, forming amalgam alloys. Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to confirm the presence of gold in items, giving rise to the term "the acid test." Gold has been a valuable and highly sought-after precious metal for coinage, jewelry, and other arts since long before the beginning of recorded history. Gold standards have been a common basis for monetary policies throughout human history, later being supplanted by fiat currency starting in
Metal Gear Acid forces team to investigate, but the team is obliterated by armed resistance. With no other options and time running out, the US government calls Solid Snake to infiltrate the laboratory, discover the nature of Pythagoras, and to rescue Senator Hach. According to an interview originally published by "Electronic Gaming Monthly" with the game's producer, Masahiro Hinami, the 'Acid' part of the title actually has three different meanings. The first meaning refers to "Acid's" departure from the previous "Metal Gear" games in terms of style, which is an analogue to acid's ability to dissolve metal. The second is a reference to