Having thus ascertained, as far as possible, the ratio of increase subsequent to the first census, we may now proceed to an examination of the course of affairs in the period which had preceded it. In 1714, the number of blacks was 58,850, and they were dispersed throughout the provinces from New Hampshire to Carolina, engaged, to a large extent, in labours similar to those in which were engaged the whites by whom they were owned. One-half of them may have been imported. Starting from this point, and taking the natural increase of each decennial period at 25 per cent., as shown to have since been the case, we should obtain, for 1750, about 130,000. The actual quantity was 220,000; and the difference, 90,000, may be set down to importation. Adding, now, 25 percent, to 220,000, we obtain, for 1760, 275,000; whereas the actual number was 310,000, which Would give 35,000 for importation. Pursuing the same course with the following periods, we obtain the following results:-- Actual Natural Actual Years Number. Increase. Increase. Importation. ----- ------- --------- --------- ------------ 1760..... 310,000..... 77,500..... 152,000..... 74,500 1770..... 462,000..... 115,500..... 120,000..... } 1780..... 582,000..... 140,500..... 170,000..... } 34,000 1790..... 752,000, number given by first census. For a large portion of the period from 1770 to 1790, there must have been a very small importation; for during nearly half the time the trade with foreign countries was almost altogether suspended by the war of the revolution. If we add together the quantities thus obtained, we shall obtain a tolerable approximation to the number of slaves imported into the territory now constituting the Union, as follows:-- Prior to 1714..................................... 30,000 1715 to 1750...................................... 90,000 1751 to 1760...................................... 35,000 1761 to 1770...................................... 74,500 1771 to 1790...................................... 34,000 And if we now estimate the import subsequent to 1790 at even........................ 70,000 ------- We obtain as the total number................... 333,500 =======