In subsequent years the earnings of the portions of the Central and Union Pacific which had received no bond subsidies were credited, in so far as they arose from government business, as a part of the 5 per cent of net earnings which these companies were required to apply to the eventual retirement of the government debt. This meant a considerable amount of bookkeeping, which was increased by other claims of the companies of which no detailed mention is here made. Indeed, when the final settlement was concluded between the Central Pacific and the government, credits to this one company were allowed by the United States to the amount of no less than $1,162,939.48.[548] Definition of Net Earnings In addition to the controversy over earnings on government transportation over non-bond-aided lines, there developed a second difference of opinion over the calculation of the net earnings of the Pacific railroads. It has already been observed that the Law of 1862, as interpreted by the Supreme Court, allowed the Pacific railroad companies to charge expenditures for additions and improvements to operating expenses, and thus to reduce their net earnings, upon the size of which the rate of provision for repayment of the government debt depended. The Central Pacific insisted that the same practice was legitimate under the Thurman law. But in this last-named legislation the wording of the clause relating to net earnings had been changed. In 1862 no definition of net earnings had been given. In 1878 it was provided that net earnings should be calculated “by deducting from the gross amount of their [the Pacific railroads’] earnings, respectively, the necessary expenses actually paid within the year in operating the same and keeping the same in a state of repair, and also the sums paid by them respectively within the year in discharge of interest on their first mortgage bonds.” This was deliberately intended as an amendment of the Act of 1862. As Mr. Thurman told the Senate, it was his intention to leave the question of the nature of the net earnings, so far as the past was concerned, for the decision of the Supreme Court without any retroactive legislation at all, but to define net earnings for the future. In spite of the apparently clear wording of the law, and the definite expression of the views of the Senate Committee on the Judiciary at the time the act was passed, the Central Pacific still maintained that it possessed the right to deduct expenditures for improvements and betterments from gross earnings, in the process of arriving at the figure of net earnings upon which its contributions toward the retirement of government indebtedness were in part based. A decision of the Court of Claims and another by the Supreme Court of the United States were necessary before this position was abandoned.[549]