After serving an apprenticeship of six years with a doctor in Philadelphia, he went for two years to Edinburgh, where he attached himself chiefly to William Cullen.
It was the necessary apprenticeship to his brilliant diplomatic career.
When this was done the local legislatures saw that the slaves would no longer work for the masters; they accordingly cut off two years of the indentured apprenticeship, and gave freedom to the slaves in August 1838 instead of 1840.
A system of apprenticeship for seven years was established as a transitional preparation for liberty.
He was fond of reading, and before the end of his apprenticeship had read more than a thousand volumes.