Though he owned slaves (perhaps upward of 600 through the course of his life by inheritance and natural increase), Thomas Jefferson disliked the institution and hoped for its gradual extinguishment. The original draft of the Declaration of Independence contained an attack on slavery. It was removed by a committee decision in deference to forming a union of both North and South.
In this excerpt from Notes on the State of Virginia, Jefferson outlined a number of reforms among which was this plan for gradual emancipation.
August Glen-James, editor
It will probably be asked, Why not retain and incorporate the blacks into the state, and thus save the expence of supplying, by importation of white settlers, the vacancies they will leave?
To emancipate all slaves born after passing the acts [i.e., the "act" containing several reforms for the newly formed commonwealth]. The bill reported by the revisors does not itself contain this proposition; but an amendment containing it was prepared, to be offered to the legislature whenever the bill should be taken up, and further directing, that they should continue with their parents to a certain age, then be brought up, at the public expence, to tillage, arts or sciences, according to their geniusses, till the females should be eighteen, and the males twenty-one years of age, when they should be colonized to such place as the circumstances of the time should render most proper, sending them out with arms, implements of household and of the handicraft arts, feeds, pairs of the useful domestic animals, &c. to declare them a free and independent people, and extend to them our alliance and protection, till they shall have acquired strength; and to send vessels at the same time to other parts of the world for an equal number of white inhabitants; to induce whom to migrate hither, proper encouragements were to be proposed.
It will probably be asked, Why not retain and incorporate the blacks into the state, and thus save the expence of supplying, by importation of white settlers, the vacancies they will leave? Deep rooted prejudices entertained by the whites; ten thousand recollections, by the blacks, of the injuries they have sustained; new provocations; the real distinctions which nature has made; and many other circumstances, will divide us into parties, and produce convulsions which will probably never end but in the extermination of the one or the other race.