The chief duty of the National Government in connection with the currency of the country is to coin money and declare its value. Grave doubts have been entertained whether Congress is authorized by the Constitution to make any form of paper money legal tender. The present issue of United States notes has been sustained by the necessities of war; but such paper should depend for its value and currency upon its convenience in use and its prompt redemption in coin at the will of the holder, and not upon its compulsory circulation. These notes are not money, but promises to pay money. If the holders demand it, the promise should be kept.