The red leather-bound book had long gone unnoticed, possibly for decades, shuffled around until an archivist stumbled upon it in the rows of shelves on the third floor of the library at Union College and passed it on to a librarian to be cataloged.

The librarian, John Myers, carefully flipped through its fraying brown pages. He found the title: “Gaines Universal Register,” or “Columbian Kalendar for the year of Our Lord 1793.” He figured out it was an almanac, printed in New York and filled with information — like the fledgling nation’s senators and its president, listed as George Washington Esq. There were personal notes, too. Mr. Myers saw that the book’s owner, Philip J. Schuyler, a businessman from a prominent family, had jotted down instructions on preserving beef in the summer months and stuffed a letter into the accordion folder built into the book’s cover.

Then, Mr. Myers found an envelope slipped into the almanac, its paper as brittle as the rest of the book’s pages. It was inscribed in cursive with initials that he did not recognize and at the top, “Washington’s Hair.” Inside, he found a lock of grayish-colored hair tied together with thread.