Thomas Jefferson corresponded briefly with Robert Pleasants, a Quaker living in Henrico County, Virginia, on the subject of public education for enslaved children. Pleasants first wrote to Jefferson in June of 1796, asking Jefferson about his thoughts on instructing slaves. Jefferson responded by suggesting that his failed 1778 Bill for the More General Diffusion of Knowledge could be revised and resubmitted to include African American children. Pleasants was amenable to this idea, but felt that the law would never pass in the face of general prejudice against educating African-Americans.
1796 June 1. (Robert Pleasants to Jefferson). "Conceiving the instructions of black children to be a duty we owe to that much degraded part of our fellow creatures and probably would tend to the spiritual and temporal advantage of that race as well as to the community at large, in fitting them for freedom which at this enlightened day is generally acknowledged to be their right, I have much desired to see some suitable steps taken to promote such worth and believing the to be a real friend to the cause of liberty, and endowed with ability and influence in regulating & promoting sutable [sic] plans for such a purpose..."
1796 August 27. (Jefferson to Robert Pleasants). "...the establishment of the plan of emancipation of it should precede I am not prepared to decide...I venture therefore to suggest what alone can, in my opinion, accomplish the general object. Among the laws proposed in what was called the Revised code printed in 1784. was a bill entitled 'for the more general diffusion of knowledge'...Very small alterations would make it embrace the object of your paper, it's effect would be general, and the means for carrying it on would be certain and permanent. Permit me therefore to suggest to you the substitution of that as a more general and certain means of providing for the instruction of the slaves, and more desireable [sic] as they would in the course of it be mixed with those of free condition. Whether, for their happiness, it should extend beyond those destined to be free, is questionable. Ignorance and despotism seem made for each other."
1797 February 8. (Robert Pleasants to Jefferson). "...I can't help fearing that the prevailing prejudices against that unfortunate race of people, will be an obstruction to an equal participation of the proposed benefit...:" 
↑ Please note that this list should not be considered comprehensive.