Alfred Nobel was born in Stockholm on October 21, 1833. By the age of 17 he was fluent in Swedish, Russian, French, English and German. Early in his life he had a huge interest in English literature and poetry as well as in chemistry and physics. Alfred's father disliked his interest in poetry and found his son rather introverted. In order to widen Alfred's horizons his father sent him to different institutions for further training in chemical engineering. During a two-year period he visited Sweden, Germany, France and the United States. He came to enjoy Paris the best. There he worked in the private laboratory of Professor T. J. Pelouze, a famous chemist. He also met the young Italian chemist Ascanio Sobrero who, three years earlier, had invented nitroglycerine.

Now nitroglycerine was considered too dangerous to be of any practical use. Although its explosive power greatly exceeded that of gunpowder, the liquid would explode in a very unpredictable manner if subjected to heat and pressure. Alfred Nobel became very interested in nitroglycerine and how it could be put to practical use in construction work. He also realized that the safety problems had to be solved and a method had to be developed for the controlled detonation of nitroglycerine.

Together with his father he performed experiments to develop nitroglycerine as a commercially and technically useful explosive. They did have a few accidents where several explosions did happen, including one in which his brother Emil and several other persons were killed. This convinced the authorities of the city that nitroglycerine production was just too dangerous. So they forbade further experimentation with nitroglycerine in the Stockholm city limits and he had to move his experimentation to a barge anchored on a lake. But of course Alfred was not discouraged and in 1864 he was able to start mass production of nitroglycerine. To make the handling of nitroglycerine safer he experimented 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 University of Chicago demonstrated that when exposed to an energy source, such as ultraviolet radiation, these compounds and water might react to produce compounds essential for the formation of living matter.

In 1960 Urey made recommendations in support of space exploration to determine the origin of the solar system and the possibility of life on other planets. He died on Jan. 5, 1981, in La Jolla, Calif.

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