The National Labor Union centered on the passage of an eight-hour law for employes of the Federal government. It was believed, perhaps not without some justice, that the effect of such law would eventually lead to the introduction of the same standard in private employment--not indeed through the operation of the law of supply and demand, for it was realized that this would be practically negligible, but rather through its contagious effect on the minds of employes and even employers. It will be recalled that, at the time of the ten-hour agitation of the thirties, the Federal government had lagged about five years behind private employers in granting the demanded concession. That in the sixties the workingmen chose government employment as the entering wedge shows a measure of political self-confidence which the preceding generation of workingmen lacked. The first bill in Congress was introduced by Senator Gratz Brown of Missouri in March 1866. In the summer a delegation from the National Labor Union was received by President Andrew Johnson. The President pointed to his past record favorable to the workingmen but refrained from any definite promises. Finally, an eight-hour bill for government employes was passed by the House in March 1867, and by the Senate in June 1868. On June 29, 1868, President Johnson signed it and it went into effect immediately. The result of the eight-hour law was not all that the friends of the bill hoped. The various officials in charge of government work put their own interpretations upon it and there resulted much diversity in its observance, and consequently great dissatisfaction. There seemed to be no clear understanding as to the intent of Congress in enacting the law. Some held that the reduction in working hours must of necessity bring with it a corresponding reduction in wages. The officials' view of the situation was given by Secretary Gideon Wells. He pointed out that Congress, by reducing the hours of labor in government work, had forced upon the department of the Navy the employment of a larger number of men in order to accomplish the necessary work; and that at the same time Congress had reduced the appropriation for that department. This had rendered unavoidable a twenty percent reduction in wages paid employes in the Navy Yard. Such a state of uncertainty continued four years longer. At last on May 13, 1872, President Grant prohibited by proclamation any wage reductions in the execution of the law. On May 18, 1872, Congress passed a law for the restitution of back pay.