The currency denominated United States notes and commonly known as greenbacks was issued in large volume during the late Civil War and was intended originally to meet the exigencies of that period.  It will be seen by a reference to the debates in Congress at the time the laws were passed authorizing the issue of these notes that their advocates declared they were intended for only temporary use and to meet the emergency of war.  In almost if not all the laws relating to them some provision was made contemplating their voluntary or compulsory retirement.  A large quantity of them, however, were kept on foot and mingled with the currency of the country, so that at the close of the year 1874 they amounted to $381,999,073.

Immediately after that date, and in January, 1875, a law was passed providing for the resumption of specie payments, by which the Secretary of the Treasury was required whenever additional circulation was issued to national banks to retire United States notes equal in amount to 80 per cent of such additional national-bank circulation until such notes were reduced to $300,000,000.  This law further provided that on and after the 1st day of January, 1879, the United States notes then outstanding should be redeemed in coin, and in order to provide and prepare for such redemption the Secretary of the Treasury was authorized not only to use any surplus revenues of the Government, but to issue bonds of the United States and dispose of them for coin and to use the proceeds for the purposes contemplated by the statute.

In May, 1878, and before the date thus appointed for the redemption and retirement of these notes, another statute was passed forbidding their further cancellation and retirement.  Some of them had, however, been previously redeemed and canceled upon the issue of additional national-bank circulation, as permitted by the law of 1875, so that the amount outstanding at the time of the passage of the act forbidding their further retirement was $346,681,016.

The law of 1878 did not stop at distinct prohibition, but contained in addition the following express provision: 

And when any of said notes may be redeemed or be received into the Treasury under any law from any source whatever, and shall belong to the United States, they shall not be retired, canceled, or destroyed, but they shall be reissued and paid out again and kept in circulation.

This was the condition of affairs on the 1st day of January, 1879, which had been fixed upon four years before as the date for entering upon the redemption and retirement of all these notes, and for which such abundant means had been provided.

The Government was put in the anomalous situation of owing to the holders of its notes debts payable in gold on demand which could neither be retired by receiving such notes in discharge of obligations due the Government nor canceled by actual payment in gold.  It was forced to redeem without redemption and to pay without acquittance.