PUBLIC LAWS-CHS. 382-384-JULY 30, 1947 Appropriations au- thorized. Authority of Secre- tary. 45 Stat. 1057; 54 Stat. 774. 43U. .S . i 617- 617t, 618-418o. July 30, 1947 [S. 13s] [Public Law 273] Public lands. Sale of Isolated, etc., tracts. July 30, 1947 [IS.1463] [Public Law 274] Immigration Act of 1917, amendment. predicating the repayment obligations of the various lands within said project on their respective ability, as determined by the Secretary, to share the burdens thereof, he may provide for the equitable appor- tionment of said general repayment obligation to the lands benefited on a unit basis in accordance with the extent of the benefit derived from the project, the character of soil, topography, and such other factors as he deems relevant, and he may provide for a system of variable payments under which larger annual payments will be required during periods of above-normal production or income and lesser annual payments will be required during periods of subnormal production or income. SEO. 6 . There are hereby authorized to be appropriated, from time to time, out of any money in the Treasury not otherwise appropriated, such moneys as may be necessary to carry out the provisions of this Act. SEO. 7 . The Secretary is authorized to perform such acts, to make such rules and regulations, and to include in contracts made under the authority of this Act such provisions as he deems proper for carrying out the provisions of this Act; and in connection with sales or exchanges under this Act, he is authorized to effect conveyances without regard to the laws governing the patenting of public lands. Wherever in this Act functions, powers, or duties are conferred upon the Secretary, said functions, powers, or duties may be performed, exercised, or discharged by his duly authorized representatives. SEC. 8 . This Act shall be deemed a supplement to and part of the reclamation law. Nothing in this Act shall be construed to amend the Boulder Canyon Project Act of December 21, 1928, as amended by the Boulder Canyon Project Adjustment Act of July 19, 1940. Approved July 30, 1947. [CHAPTER 383] AN ACT To amend section 2455 of the Revised Statutes, as amended, to increase the size of isolated or disconnected tracts or parcels of the public domain which may be sold, and for other purposes. Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That section 2455 of the Revised Statutes (43 U. S . C., sec. 1171), as amended, is hereby amended by striking out the words "seven hundred and sixty" and inserting in their place the words "one thousand five hundred and twenty". The said section is further amended by striking out the words "one hundred and sixty" in the second proviso and inserting in their place the words "seven hundred and sixty". Approved July 30, 1947. [CHAPTER 384] AN ACT To amend section 12 of the Immigration Act of 1917. Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That section 12 of the Act entitled "An Act to regulate the immigration of aliens to, and the residence of aliens in, the United States , approved February 5, 1917, as amended (39 Stat. 882; U. S . C., title 8, sec. 148), is amended to read as follows: [61 STAT.