The Historical Society of Olde Northfield announces that the Palmer House Museum will be open for visitors on May 21, from 2 to 4 p.m., and on May 29, from 9 to 11 a.m. The summer schedule for the museum is from 2 to 4 p.m. on June 11 and 25; July 9 and 23; and Aug. 13 and 27.