A small, private university in central Ohio says an $8 million donation from an alumni couple will help restore an academic building listed on the National Register of Historic Places. The gift to Ohio Wesleyan University in Delaware will be used to restore its Merrick Hall, which originally opened in 1873 and has been closed for more than two decades. The updated three-story, blue limestone building is expected to reopen in 2015 and include classroom and event spaces. The university says the $8 million donation marks the largest single gift in the 171-year history of the school. The donors, who met at the school, have decided to remain anonymous. The university has about 1,850 students.