ented with different additives. He soon found that mixing nitroglycerine with silica would turn the liquid into a paste, which could be shaped into rods, which could be dropped into drilled holes in rocks. In 1867 he patented this material under the name of dynamite. By the time of his death in 1896 he had 355 patents.In 1934 the American scientist Harold Clayton Urey won the Nobel Prize for chemistry for his discovery of the heavy form of hydrogen known as deuterium. He was also a key figure in the development of the atomic bomb and made fundamental contributions to a theory of the origin of the Earth and other planets that is now widely accepted. Urey's deuterium research began in the 1920s when he distilled some liquid hydrogen, concentrating its deuterium form. In 1931 he and his associates announced their discovery of heavy water, composed of an atom of oxygen and two atoms of deuterium. He also separated radioactive isotopes of carbon, oxygen, nitrogen, and sulfur, and examined their properties. During World War II he directed a research program at Columbia that became a vital part of the Manhattan Project, which developed the atomic energy program in the United States. Urey's group provided the fundamental information for the separation of the isotope uranium-235 from the more abundant isotope uranium-238 and investigated methods for concentrating heavy hydrogen and separating boron isotopes. After the war his work with the heavy isotope oxygen-18 led him to devise methods for determining ocean temperatures as long as 180 million years ago. This led him to study the relative abundances of the elements on Earth and to develop a theory of the origin of the elements and of their abundances in the sun and other stars. Urey theorized that the early atmosphere of the Earth was probably like the atmosphere now present on Jupiter, which is rich in ammonia, methane, and hydrogen. One of his students working in his laboratory at the Unive...
