In the construction of any future dam, steam plant, or other facility, to be used in whole or in part for the generation or transmission of electric power the Board is authorized and empowered to issue on the credit of the United States and to sell serial bonds not exceeding $50,000,000 in amount, having a maturity not more than fifty years from the date of issue thereof, and bearing interest not exceeding 3½ per centum per annum. Said bonds shall be issued and sold in amounts and prices approved by the Secretary of the Treasury, but all such bonds as may be so issued and sold shall have equal rank. None of said bonds shall be sold below par, and no fee, commission, or compensation whatever shall be paid to any person, firm, or corporation for handling, negotiating the sale, or selling the said bonds. All of such bonds so issued and sold shall have all the rights and privileges accorded by law to Panama Canal bonds, authorized by section 8 of the Act of June 28, 1902, chapter 1302, as amended by the Act of December 21, 1905 (ch. 3, sec. 1, 34 Stat. 5). All funds derived from the sale of such bonds shall be paid over to the Corporation.