Where it shall be made to appear to the satisfaction of the Secretary of the Interior with reference to any lawful pending desert-land entry made prior to July 1, 1925, under which the entryman or his duly qualified assignee under an assignment made prior to March 4, 1929, has in good faith expended the sum of $3 per acre in the attempt to effect reclamation of the land, that there is no reasonable prospect that he would be able to secure water sufficient to effect reclamation of the irrigable land in his entry or any legal subdivision thereof, the Secretary of the Interior may, in his discretion, allow such entryman or assignee ninety days from notice within which to pay to the officer designated by the Secretary of the Interior of the United States land office 25 cents an acre for the land embraced in the entry and to file an election to perfect title to the entry under the provisions of this section, and thereafter within one year from the date of filing of such election to pay to such officer the additional amount of 75 cents an acre, which shall entitle him to a patent for the land: Provided, That in case the final payment be not made within the time prescribed the entry shall be canceled and all money theretofore paid shall be forfeited.