Draper, John William (1811–1882)
Most of Draper's chemical work was done in the field of photochemistry. He was one of the first scientists to use Louis Daguerre's new invention of photography and took the first photograph of the Moon in 1840 (see daguerreotype) and in the same year took a photograph of his sister, Dorothy, which is the oldest surviving photographic study of the human face. In 1843 he obtained the first photographic plate of the solar spectrum. On the theoretical level, Draper was one of the earliest to grasp that only those rays that are absorbed produce chemical change and that not all rays are equally powerful in their effect. He also, in a series of papers, showed that the amount of chemical change is proportional to the intensity of the absorbed radiation multiplied by the time it has to act. Draper's work was continued and largely confirmed by the work of Robert Bunsen and Henry Roscoe in 1857.
Related category• CHEMISTS
• ASTRONOMERS AND ASTROPHYSICISTS
Home • About • Copyright © The Worlds of David Darling • Encyclopedia of Alternative Energy • Contact