9. After twenty-eight years from the first adoption, this plan of gradual emancipation will first begin to manifest its effects, by the complete emancipation of one twenty-eighth part of the post-nati free born during that period each succeeding year, for twenty-eight years more; their numbers will be, 277500/28, or 9,910. These will be all females. 10. It being admitted that the negroes double every thirty years, the supposition that in forty-five years, their numbers will be half as many more as in thirty, will not be very erroneous, if so, the whole race of them at that period will be 900,000. 11. Their numbers will stand thus: Ante-nati, 60,000 Post-nati, 840,000 ---- 900,000. 12. After twenty-eight years are past, the number of slaves born must continually diminish. Suppose their number born in the last 17 years, to be one-fourth as many as those born in the preceding twelve years, they will be 52500/4, or 13,125. 13. The slaves in Virginia in forty-five years will then be, ante-nati, 60,000 Post-nati males born in the first sixteen years, 120,000 Ditto, born in the next twelve years 52,500 Ditto, born in the last seventeen years, 13,125 ---- 245,625. At this period the emancipation of males will begin. 14. But after twenty eight years it has been shewn that 9,910 negroes will annually arrive at the age of emancipation, their whole number in forty-five years will be 168,470. 15. The state of the negroes at the end of 45 years, will then be, slaves, 245,625 Post-nati fully emancipated (females), 168,470 Post-nati not emancipated, 485,905 ---- 900,000. 16. In sixty years the whole number of negroes will be 1,200,000. 17. At that period the whole of the present race will be extinct; and we may also infer that one half of those born in the first thirty years will be also extinct; the number of slaves born in that period has been shewn, (prop. 7.) to be 172,500, the number of these then living will be 172,500/2, or 86,250. 18. One half of the post-nati free born, during that period, being now fully emancipated, may be likewise presumed to be extinct; their numbers (prop. 8.) will be, 277,500/2, or 138,750. 19. The state of the negroes at the end of sixty years, will therefore be: Slaves born during the first thirty years, 86,250 Ditto born after that period, 13,125 Post-nati fully emancipated, 138,750 Post-nati under 28 years of age, 961,875 ---- 1,200,000. 20. At the end of ninety years the number of negroes will be 2,400,000 21. Of this number, those only born after the first thirty years, being supposed to be living, the number of slaves (prop. 12) will then be reduced to 13,125.