For the Purpose of the Erection and Repairs of Lighthouses, and of other extraordinary Expenses connected with the said Services or any of them, the Commissioners of Her Majesty's Treasury are authorized from Time to Time, upon the Application of the Board of Trade, to advance out of the growing Produce of the Consolidated Fund of the United Kingdom such Sums of Money, upon such Terms, and at such Rate of Interest as they may think fit, and to pay the same into the said Mercantile Marine Fund Account, so nevertheless that the whole Sum for the Time being due in respect of such Advances shall never at any One Time exceed Two hundred thousand Pounds; and upon any Advance being so made, the Sum so advanced and the Interest shall be a Charge on the said Mercantile Marine Fund, and upon the Tolls, Rates, Fees, and Payments so to be carried thereto as aforesaid; and the Board of Trade shall make such Provision for the Repayment thereof out of the said Fund, either by forming a Sinking Fund or otherwise, as the said Commissioners may require; provided that no such Advance shall prevent any lawful Reduction of any of the said Tolls, Rates, Fees, or Payments if such Reduction be assented to by the said Commissioners.