In 1796 he began the study of law, completing his preparation in 1802 at New York, where he studied under William Peter Van Ness (1778-1826), an eminent lawyer and later Aaron Burr's second in the duel with Alexander Hamilton.
Hamilton's action in counselling Federalists not to vote for Burr for governor just as he had counselled them not to support Burr against Jefferson in 1800, was one of the contributary causes of Burr's hostility to Hamilton which ended in the duel (July 1804) in which Burr killed Hamilton.
The College of New Jersey, now Princeton University, was situated here from 1747 to 1756, for all but the first few months under the presidency of the Rev. Aaron Burr, who published in 1752 the well-known Newark Grammar, long used in Princeton and originally prepared for Burr's very successful boys' school in Newark.
Hamilton had opposed Burr's aspirations for the vice-presidency in 1792, and had exerted influence through Washington to prevent his appointment as brigadier-general in 1798, at the time of the threatened war between the United States and France.
It was also in a measure his efforts which led to Burr's lack of success in the New York gubernatorial campaign of 1804; moreover the two had long been rivals at the bar.
Jumel (1769-1865), a rich New York widow; the two soon separated, however, owing to Burr's having lost much of her fortune in speculation.
For the traditional view of Burr's conspiracy, see Henry Adams's History of the United States, vol.
He removed to Richmond in 1803, and during his last years was a leader of the Virginia bar; in 1807 he was one of Aaron Burr's counsel.
At Burr's trial at Richmond in 1807 Eaton was one of the witnesses, but his testimony was unimportant.