Hugh Williamson (5 December 1735 - 22 May 1819).Born in Chester County, Pennsylvania, educated at the College of Philadelphia (University of Pennsylvania), trained in medicine in Europe, Williamson had a distinguished scientific career before the American Revolution (publishing on medicine, astronomy, and electricity). His scientific interests took him to London, where in the early 1770s, he also pleaded the American case to a British opposition (as did his friend, Benjamin Franklin, whose career also took him to London in the early 1770s).
 

Williamson returned to America in 1776, and established himself as a merchant in North Carolina (trading with America's new ally, the French). During the war he was state surgeon general, and during the bitter fighting in the Carolinas in 1780-1781, he accompanied the army as a doctor/surgeon.
 

In the early 1780s, as the war wound down, Williamson was elected to the state assembly (House of Commons) and the Continental Congress - where he spoke in favor of a stronger national government. At Philadelphia he worked with the Virginia and Pennsylvania delegations in support of a strong, national government, and he also helped fashion the compromise giving Congress the power to end the slave trade after 1808 (Williamson was opposed to slavery). Despite his efforts to secure ratification, North Carolina did not join the new union initially. Only after Washington's election, and the meeting of a second ratification convention, did North Carolina become the twelfth state in the new nation.
 
 
 

Sources: see especially his essay "Letters to Sylvius" published in the American Museum in 1787; and reprinted in most anthologies of the constitutional debates.