But while the census shows that the power to admit slaves was exercised freely during the twenty years that followed the adoption of the Constitution of the United States, it also shows that the States which insisted on retaining it for that period could well afford to surrender it at the stipulated time. In 1810, the proportion of the blacks of North Carolina to the whole population was 32.24 per cent, and in 1850 it was 36.36; in South Carolina the proportion in 1810 was 48.4, and in 1850, 58.93; in Georgia, in 1810 it was 42.4, and in 1850, 42.44. It is not probable, therefore, that the prosperity of those States has been diminished by the discontinuance of the slave-trade; for it is not likely that they could well sustain a much larger ratio of the blacks to the whites than that which now exists, and which will probably continue to be maintained at about the same point for a long period of time. CHAPTER XI. REPORT OF THE COMMITTEE OF DETAIL, CONTINUED.--THE REMAINING POWERS OF CONGRESS.--RESTRAINTS UPON CONGRESS AND UPON THE STATES. In the last preceding chapter, the reader has traced the origin of the revenue and commercial powers, and of certain restrictions applied to them in the progress of those great compacts, by means of which they became incorporated into the Constitution. We have now to examine some other qualifications which were annexed to those powers after the first draft of the instrument had been prepared and reported by the committee of detail. That committee had presented a naked power to lay and collect taxes, duties, imposts, and excises,[232] with a certain restriction as to the taxation of exports, the final disposition of which has been already described; but they had designated no particular objects to which the revenues thus derived were to be applied. The general clause embracing the revenue power was affirmed unanimously by the Convention, on the 16th of August, leaving the exception of exports for future action. At a subsequent period we find the words, "to pay the debts and provide for the common defence and general welfare of the United States," added to the clause which empowers Congress to levy taxes and duties; and it is a somewhat important inquiry, how and with what purpose they were placed there.