BUFFALO -- Jacob Akiba Marinsky, a chemist who co-discovered promethium, element 61 on the periodic table, died Sept. 1 in his Buffalo home after a short illness. He was 87.
While working for the Manhattan Project in 1945, Dr. Marinsky and associates Lawrence Glendenin and Charles Coryell isolated promethium, a radioactive element and byproduct of uranium fission.
Promethium salts light up in the dark with a pale blue or greenish glow due to their high radioactivity. Commercially, promethium, a rare earth metal, was used in such objects as watch dials.
Dr. Marinsky and his colleagues named the element for Prometheus of Greek mythology, who stole fire from heaven for humanity.
Since promethium decays rapidly, it was isolated much later than similar elements near it on the periodic table. It ''was an astounding thing to discover in the middle of the periodic table, so late in the history of science," said Harry F. King, a professor of chemistry at the State University of New York, told The New York Times.
Born in Buffalo, Dr. Marinsky entered the University at Buffalo at age 16 and received a bachelor's degree in chemistry. He earned a doctorate in chemistry from Massachusetts Institute of Technology.
He was a professor emeritus at the University at Buffalo at the time of his death.
Dr. Marinsky was a Fulbright Research Scholar at the Weizmann Institute of Science in Israel in the early 1960s. In 1990, the University at Buffalo awarded him the Clifford Furnas Memorial Award for graduates whose scientific accomplishments have brought prestige to the university.
''He was a very ethical person," said his daughter, Jane, of Buffalo. ''He always worried about doing what was right. He set a good example for all of us."
He signed a petition against dropping the atomic bomb on Japan in 1945 and favored disarmament during the arms race. He was a supporter of the civil rights movement and an early opponent of the Vietnam War.
When the University of Buffalo demanded in the late 1960s that faculty sign a loyalty oath to the United States, Dr. Marinsky refused, citing a violation of civil liberties.
In addition to his daughter, Dr. Marinsky leaves his wife of 63 years, Ruth; three other daughters, Deborah of Princeton, N.J.; Elyse Friedman of Newton, Mass.; and Susan Cramer of Blacksburg, Va.; 10 grandchildren, and 2 great-grandchildren