William Penn (detail), 1894, cast bronze (37 feet tall), by Alexander Milne   Calder. Located City Hall, Philadelphia   Conservation included pretreatment condition analysis as well as thorough   documentation of all project phases: ultra-high-pressure water cleaning (a   process introduced to the industry by Moorland Studios), structural and   surface repairs, casting new pieces, patination, and the design and application   of a protective coating. Maintenance ongoing   next >