EASTHAM — The Eastham Historical Society made a rare find last month while dusting and sorting items at the 1869 Schoolhouse Museum: a document signed by Samuel Adams.

“Joe [Mistretta, a museum director] was cleaning off some of these documents with a brush. He came in and said, ‘I’m not sure what I found here but I think this is important,’ ” said Society President Eileen Seaboldt.

The document, donated by Mr. and Mrs. George Myrick of Delmar, N.Y., was kept between two panes of glass sealed with masking tape. Dated June 16, 1795, it appoints Elijah Knowles of Eastham as justice of the peace and is signed by Samuel Adams as governor of Massachusetts. The Elijah Knowles house is still standing, just past the Capt. Penniman House on the way to Fort Hill.

National Seashore Park Historian William Burke examined the document and recommended the group contact a conservator. “It’s a fabulous document,” said Burke. Adams’s signature, he noted, was “a really fine looking, neat, articulate signature.”

The society has contacted the Northeast Document Conservation Center. “We’re in the discovery stage,” said Seaboldt. “We’re all basking in excitement here.”

On the back of the document is a penciled tally of George Washington’s first election in 1789, showing 44 votes cast in Barnstable County.

“It just shows you how informal politics could be in the 18th century,” said Burke, “when they were saying, ‘OK, how many votes does Washington have in Barnstable County?’ and tallying it up on the back of this thing.” —Linda Culhane