A tower clock was first installed sometime after Latrobe's restoration of 1802 when the cupola was raised; it was probably destroyed in the fire of 1855. The clock with the four faces one sees today was donated by the Class of 1866 at the tenth anniversary of their graduation. The works of this clock were modernized in 1919 and again in 1955; its faces are periodically re-gilded to offset weathering.

Source: Leitch p. 328ff