"Mercury as a liquid metal is capable of dissolving other metals and forming metallic solutions. These are generally called 'amalgams.' The formation of these solutions is often accompanied by the development of a large amount of heat—for instance when and sodium are dissolved... but sometimes heat is absorbed, as... when is dissolved. ...[T]he solution of metals in mercury is accompanied by the formation of definite chemical compounds of the mercury with the metals dissolved. ...[I]n many cases such compounds have undoubtedly been obtained, and their existence is clearly shown by the evident crystalline structure and characteristic appearance of many amalgams."