Goethe also wrote to Howard (via one of Goethe's English friends), requesting Howard's autobiography and process in developing his classification system. Goethe also attempted to commission German painter Caspar David Friedrich for cloud studies based on Howard's system, but Friedrich declined. However, Friedrich did begin a series of cloud studies later that year. Howard's classification system, along with Goethe's interest, resulted in a great artistic interest in clouds. Howard's work is also rumored to have inspired Shelley's poem "The Cloud" and informed John Constable's paintings and studies of skies, in addition to the writings and art of John Ruskin, who used Howard's cloud classification in his criticisms of landscape paintings in "Modern Painters".