The area continues to be called Wood's Spot. In 1909, Wood constructed the first practical liquid mirror astronomical telescope, by spinning mercury to form a paraboloidal shape, and investigated its benefits and limitations. Wood has been described as the "father of both infrared and ultraviolet photography". Though the discovery of electromagnetic radiation beyond the visible spectrum and the development of photographic emulsions capable of recording them predate Wood, he was the first to intentionally produce photographs with both infrared and ultraviolet radiation. Wood took part in the investigation of several crimes, including the Wall Street bombing. Wood also authored nontechnical works. In 1915, Wood co-wrote a science fiction novel, "The Man Who Rocked the Earth", along with Arthur Train. Its sequel, "The Moon Maker", was published the next year. Wood also wrote and illustrated two books of children's verse, "How to Tell the Birds from the Flowers" (1907), and "Animal Analogues" (1908). Wood married Gertrude Hooper Ames in 1892 in San Francisco. She was the daughter of Pelham Warren and Augusta Hooper (Wood) Ames, and the granddaughter of William Northey Hooper and the Massachusetts Supreme Court justice Seth Ames. Robert Wood died in Amityville, New York. Although physical optics and spectroscopy were Wood's main areas of study, he made substantial contributions to the field of ultrasound as well. His main contributions were photographing sound waves and investigating high-power ultrasonics. His first contribution to the field of ultrasonics was the photography of sound waves. Wood's primary research area was physical optics, but he found himself confronted with the problem of demonstrating to his students the wave nature of light without resorting to mathematical abstractions which they found confusing. He therefore resolved to photograph the sound waves given off by an electric spark as an analogy to light waves. An electric spark was used because it produces not a wave train, but a single wavefront, making it much more intuitive to study and visualize. Although this method was first discovered by August Toepler, Wood did more-detailed studies of the shock waves and their reflections. After these early contributions Wood returned to physical optics, setting aside his interest in "supersonics" for quite some time. With the entry of the United States into World War I, Wood was asked to help with the war effort. He decided to work with Paul Langevin, who was investigating ultrasound as a method for detecting submarines. While in Langevin's lab, he observed that high-powered ultrasonic waves can cause the formation of air bubbles in water, and that fish would be killed or an experimenter's hand would suffer searing pain if placed in the path of an intense sound beam.