The website of the Rodin Museum, adminstered by Philadelphia Museum of Art, provides an online project description of the conservation of Rodin's 'The Thinker'. The outdoor sculpture had been affected by 'acid rain'. During the conservation process Rodin's writings on the subject of surface finish and patination were considered and compared with examples of Rodin's 'The Thinker ' which were exhibited outdoors. Enter the link of Rodin Museum and enter 'Conservation of the Thinker'. The page 'Conserving the collection' provides publications on the conservation of Toulouse-Lautrec's 'In the Hanneton' and 'the paper choice of Mary Cassett'.