Gold parting in 1860's Australia. It is able to refine gold up to 99.5% purity. The process involves blowing a stream of chlorine gas over and through a crucible filled with molten impure gold. Impurities in the gold form chlorides before the gold does and these insoluble salts are removed from the melt by skimming the surface. Invented by Emil Wohlwill in 1874, this produces the highest purity gold (99.999%). It is an electrolytic process using pure gold for the cathode (or titanium as a starter cathode) and chloroauric acid (gold chloride-hydrochloric acid) as the electrolyte; this is made by dissolving gold
Commodity (Marxism) of socially necessary labor have the same exchange value. By contrast, prices are normally measured in money-units. For practical purposes, prices are, however, usually preferable to labour-hours, as units of account, although in capitalist work processes the two are related to each other (see labor power). The seven basic forms of commodity trade can be summarised as follows: The hyphens ("-") here refer to a transaction applying to an exchange involving goods or money; the dots in the last-mentioned circuit ("...") indicate that a value-forming process ("P") occurs "in between" purchase of commodities and the sales of different commodities. Thus,