Briefings • Gold Gains in London as Weaker Dollar Spurs Investment Demand - Gold gained in London as a weaker dollar increased demand for the metal as an alternative investment. The U.S. Dollar Index, a six-currency gauge of the greenback's strength, fell as much as 0.4 percent on speculation European offcials will agree to help Greece tackle its budget gap. Gold typically moves inversly to the U.S. currency, which climbed for a third week last week as concern about the Greek dificit weighed on the euro.