On the Wharfe, Bolton Abbey, 1858, Watercolor, sheet: 9 15/16 x 14 in. (25. 3 x 35. 6 cm), Drawings, William Callow (British, Greenwich 1812?1908 Great Missenden, Buckinghamshire), This drawing demonstrates Callow?s mastery of watercolor as a sketching medium. He applied wet pigment onto dampened paper in some portions of the sheet and used a dry-brush technique in others. Earlier in his career the artist had worked in Paris and was influenced by artists in the circle of Richard Parkes Bonington (1802-1828)