Robert P. Multhauf, 84, who was editor of Isis, the journal of the History of Science Society, for 15 years and director of the Smithsonian Institution's Museum of History and Technology in the late 1960s, died of cardiopulmonary arrest May 8 at his home in San Rafael, Calif.

Dr. Multhauf was a historian of science and technology, the first hired for the Smithsonian's newly authorized Museum of History and Technology in 1955. His views, said David DeVorkin, a curator at the National Air and Space Museum, "were in consonance with a significant postwar growth of academic interest in the history of science and technology."

"He moved to the very center of this blossoming discipline," DeVorkin said, when he became editor of Isis, the field's primary journal in the United States. Dr. Multhauf guided the journal from 1964 to 1978.

Dr. Multhauf joined the Smithsonian in 1955 as a curator of the division of engineering at the museum and two years later was named head curator of the department of science and technology. From 1966 to 1969, he served as director of the Museum of History and Technology.

Working under museums director Frank Taylor and Smithsonian secretaries Leonard Carmichael and S. Dillon Ripley, Dr. Multhauf helped to shape the historical side of the institution. He viewed historical collecting, exhibiting and research as complementary activities in a museum setting, DeVorkin said, and was convinced of the importance of historical research to the first two elements.

Dr. Multhauf worked with the Smithsonian's leadership to create curatorial positions for specific scientific and industrial lines, to revamp the process of mounting exhibits and to demand that historical expertise be maintained through active research leading to academic publishing.

Among his more significant achievements as director was the purchase of the Warshaw Collection of Business Americana, which became the foundation of the present Archives Center at the National Museum of American History. He was succeeded as director by Daniel J. Boorstin and returned to historical research, writing and editing full time.

He retired from the Smithsonian in 1987 as senior historian, a position he had held since 1969.

Dr. Multhauf also was president of the Society for the History of Technology (1969-1970) and president of the History of Science Society (1979-80).

He was born in Sioux Falls, S.D., and raised in Newton, Iowa. As a youngster, he attended the 1933 Chicago World's Fair with his family and was impressed with the exhibiting at the newly opened Chicago Museum of Science and Industry, he recalled in his oral history. The Chicago museum was one of the first institutions in the United States to adopt the methods of rational and thematic collecting rather than taxonomic collecting in the history of science and technology. It also used models, cutaways and motion to explain how things worked and grouped items together so there was some sense of change over time.

After graduating from Iowa State College in 1941, he worked as a chemist for three years at the Hercules Powder Co. of Wilmington, Del.

He was a lieutenant junior grade in the Navy during World War II and remained in the service as a chemical engineer in occupied Japan until 1947.

He received a master's degree in history in 1950 and a doctorate in medieval chemistry in 1953, both from the University of California at Berkeley. He then spent a year as a fellow at the Johns Hopkins University Department of the History of Medicine.

Dr. Multhauf wrote several published works in the history of chemistry and chemical technology, including "Neptune's Gift: A History of Common Salt" (1978), a comprehensive look at the production, uses and role of salt in modern society.

His earlier work "Origins of Chemistry" (1967) identifies how classical alchemical traditions in Western culture contributed to medical chemistry and shows how modern chemistry derives from classical efforts to understand the structure of matter, which rationalizes how chemistry became a field fostering exact experimental analysis.

Dr. Multhauf also prepared and published catalogues of the Museum of History and Technology collections, ranging from 19th century astronomical instrumentation to the development of 20th century radiosonde technologies.

His marriage to Mary B. Smith ended in divorce.

He lived in Washington until the late 1980s, when he moved to San Rafael.

Dr. Multhauf continued to collect books and images and to write, edit and publish. He sold a large portion of his library to the newly created Max Planck Institute for the History of Science in Berlin, where it became the core of the collection.

Survivors include his wife, whom he married in 1962, Lettie Stibbe Multhauf of San Rafael; three stepsons, Bram Dresden of Greenbrae, Calif., and Ben Dresden and Stephen Bevis, both of Novato, Calif.; a sister; seven grandchildren; and 11 great-grandchildren.

Robert P. Multhauf was a leading American scholar in the history of science and technology, edited the field's journal and organized the Smithsonian's collection.