Notwithstanding the provisions of section 65 of this Charter, the Special Reserve Fund of the Light Department therein provided for shall not be increased in any one year by more than 10 percent of the net earnings of said Department for the previous year, unless a majority of the legal voters of the City present and voting thereon at the annual City meeting to be held on the first Tuesday in March, 1950, shall vote favorably upon the following question, to be voted upon by ballot: "Shall the City Council, with the approval of the Board of Light Commissioners, be authorized to increase the Reserve Fund of the Light Department by such part of the Department earnings as it may deem advisable?"