The Secretary of the Treasury is authorized and directed to transfer to the credit of the reclamation fund, created by section 391 of this title, a sum equal to the difference between (1) 52½ per centum of the moneys which the Secretary of the Treasury shall determine to have accrued to the United States from lands within the naval petroleum reserves, except those in Alaska, from February 25, 1920, to June 30, 1938, inclusive, and (2) the total of all sums advanced to the reclamation fund under the provisions of sections 397 and 398 to 400 of this title, and under the provisions of sections 391a and 391b of this title, and not reimbursed by transfer from the reclamation fund to the general funds in the Treasury. The transaction provided for in this section shall be deemed to have effected a complete reimbursement to the general funds in the Treasury of all sums advanced to the reclamation fund under the provisions of such sections 391a, 391b, 397, and 398 to 400 of this title.