John William Draper (1811-1882), a physician, did extensive work on the nature of radiant heat, in proving that the rays of all wavelengths are capable of producing chemical changes, in the determination on the nature of the rays absorbed in the growth of plants in sunlight, and on the interpretation of capillary phenomena in physiology and in plant growth. He used intensively and smartly the science and art of photography, then in its infancy, to give visual proofs of his results. He was one of the first to photograph a human face, the moon, and the solar spectrum.
- Capillary phenomenon
- Tithonic rays