At the time of the embargo's repeal, America's financial ruin was extensive, and fewer individuals were hit harder by the damage than Jefferson himself. Due to liberal spending on executive entertainments while in office, Jefferson found himself $30,000 in debt upon his retirement. While he would live on for almost two decades more, his sphere dwindled from the world stage to a handful of counties in rural Virginia. He was seen in public only on horseback, and received exclusively at Monticello rather than be received by others.
As ever, Jefferson poured himself into the continued expansion and renovation of his estate. While this mainly concerned Monticello, Jefferson also poured considerable time, money, and energy into the development of his second home. Built to an octagonal floor plan, Poplar Forest was Jefferson's retreat in Bedford County, Virginia, roughly ninety miles from Monticello.
In both of these domains, Jefferson extended his experiments with farming and gardening, working with new crops, flowers, and herbs. Additionally, he developed innovations with the plough and threshing-machine. This increased the productivity on the modest amount of farmland that he maintained among his 10,000 acres. Yields were rarely impressive due to erratic weather, and profits were minimal at best. To supplement his income, Jefferson continued to oversee the operation of the nailery, and also worked to train the best among his 150 slaves as carpenters, cobblers and tailors.
Beyond mere activity, Jefferson spent his closing years engaged in a variety of intellectual pursuits. Henry Adams, piercing as ever, drolly described Jefferson as "a martyr to the disease of omniscience," and it was a "disease" which Jefferson pursued in earnest during retirement as at no other time. Whether it was dabbling in a variety of classical and modern languages, reading up on the ancient philosophers and playwrights, collecting and classifying fossils or keeping extensive meteorological records, he seemingly had a hand in every pot.
With his love of knowledge, it was fitting that Jefferson serve an extended tenure as president of the American Philosophical Society. And to add to his list of practical distinctions, Jefferson invented or improved useful items such as the dumbwaiter and the swivel chair. Most valuable to his own uses was the redesign of Charles Wilson Peale's polygraph, employed in the production of multiple text copies. Jefferson himself valued this particular machine because it allowed him to make and save copies of his voluminous correspondence.
Never one to make enemies unduly, Jefferson had suffered from a bitter break with John Adams after the Election of 1800. Adams scornfully remarked upon toward the end of Jefferson's administration that "Mr. Jefferson has reason to reflect upon himself.... How he will get rid of his remorse in his retirement, I know not. He must know that he leaves the government infinitely worse than he found it, and that from his own error or ignorance." But before long, the old allies turned enemies were reconciled to friendship again, and enjoyed a fruitful correspondence in their old age.