Section, act Apr. 12, 1900, ch. 191, § 11, 31 Stat. 80, provided for redemption by Secretary of the Treasury of Puerto Rican silver coins known as the peso and all other Puerto Rican silver and coppers in circulation on Apr. 12, 1900, except those imported after Fespan. 1, 1900, at rate of 60 cents per peso and for recoinage of such coins into United States coins, and made United States coins sole legal tender in payment of debts, except those owing prior to Apr. 12, 1900, which were payable in Puerto Rico coins or their exchanged equivalents.