Historian Ron Chernow maintains that overseers were required to warn slaves before resorting to the lash and required Washington's written permission before whipping, though his extended absences did not always permit this.[464] Washington remained dependent on slave labor to work his farms and negotiated the purchase of more slaves in 1786 and 1787.[465]
Washington brought several of his slaves with him and his family to the federal capital during his presidency. When the capital moved from New York City to Philadelphia in 1791, the president began rotating his slave household staff periodically between the capital and Mount Vernon. This was done deliberately to circumvent Pennsylvania's Slavery Abolition Act, which, in part, automatically freed any slave who moved to the state and lived there for more than six months.[466] In May 1796, Martha's personal and favorite slave Oney Judge escaped to Portsmouth. At Martha's behest, Washington attempted to capture Ona, using a Treasury agent, but this effort failed. In February 1797, Washington's personal slave Hercules escaped to Philadelphia and was never found.[467]
In February 1786, Washington took a census of Mount Vernon and recorded 224 slaves.