NORTHUMBERLAND - The public is invited to Priestley House to help celebrate Joseph Priestley's 281st birthday Sunday.

Admission will be free between 1 and 4 p.m. Birthday cake and punch will be served in the visitors center.

Priestley was born in England March 13, 1733. The renowned scientist, political thinker and dissenting clergyman came to Northumberland in 1794 and lived there for the rest of his life. He died in the Priestley House in 1804.

Ronald Blatchley, a retired chemistry teacher who portrays Priestley, will perform 18th chemistry demonstrations in the Pond Building on the grounds at 1:30 and 2:30 p.m.

Visitors may tour the museum at their own pace, with guides in vintage costume to greet them and answer questions.

The Friends of the Joseph Priestley House operates the museum, which is owned by the Pennsylvania Historic and Museum Commission. Sunday's open house will also be part of a statewide commemoration by the commission to mark the signing of the state's charter.

Priestley House will then be open for the 2014 season from 1 to 4 p.m. Saturday and Sunday (except Easter) with tours at 1, 2 and 3 p.m. Tours at other times can be arranged by calling 570-473-9494 or by email at info@josephpriestleyhouse.org.