Rare Books and Special Collections does have a collection of rifles, swords, spears, and other armaments but Mercer’s sword is not specifically labeled. https://blogs.princeton.edu/graphicarts/2012/08/post_36.html
Several of the collection’s swords have leather belts or other straps still attached. Several have curved blades. Several could be considered heavy and/or massive weapons. We are consulting with experts but in the meantime, do you recognize Mercer’s sword?
Hugh Mercer (1726-1777) was a soldier, a physician, and a close friend to George Washington. Mercer died as a result of his wounds received at the Battle of Princeton and became a fallen hero and rallying symbol of the American Revolution.
Here might be an answer to the question: http://www.philly.com/philly/news/Sword-of-Princeton-hero-to-be-displayed-at-American-Revolution-museim.html