Samuel P. Massie Jr., a chemistry professor who was the first African American to teach at the U.S. Naval Academy, died April 10 at Mariner Healthcare Center in Laurel. He was 85 and had dementia.

Dr. Massie considered himself first and foremost a teacher, though he also gained widespread recognition for his work in chemistry. He was named one of the 75 premier chemists of the 20th century, along with Marie Curie, George Washington Carver, Kodak founder George Eastman and DNA researchers James Watson and Francis Crick.

As a young man studying for his doctoral degree, Dr. Massie worked on the Manhattan Project with scientists making liquid compounds of uranium for the atomic bomb. He conducted pioneering silicon chemistry research and investigated antibacterial agents. With two midshipmen and colleagues from the Walter Reed Army Institute of Research, he was awarded a patent for chemical agents effective in battling gonorrhea.

He received awards for research in combating malaria and meningitis, worked on drugs to fight herpes and cancer and developed protective foams against nerve gases.

Dr. Massie, a former professor at several historically black colleges who lectured on campuses nationwide, also received recognition for encouraging African American and other minority students to pursue science careers.

"Many people, some of them teachers, who unconsciously make science and mathematics too difficult feel that science and mathematics are not for the common student," he once said. "They are wrong. The depth of use may vary, but the principles remain understandable to all of us."

Samuel Proctor Massie Jr. was born in North Little Rock, Ark., the son of two schoolteachers. He read at a third-grade level by the time he entered first grade, skipped several grades and graduated from high school at 13.

Because of his age and family finances, he worked in a grocery store for a year before enrolling in Dunbar Junior College in Little Rock. After graduating, he wanted to attend the University of Arkansas, but the doors were closed to black students.

He did not allow the barefaced segregation of the day to impose limits on him. Interested in finding a cure for his father's asthma, he graduated summa cum laude in chemistry from Arkansas Agricultural, Mechanical and Normal College (now the University of Arkansas at Pine Bluff) in 1936. He received a master's degree in chemistry from Fisk University in 1940, then returned to Arkansas AM&N to teach for a year.

In 1941, Iowa State University accepted him in its doctoral program in organic chemistry but would not allow him to live on campus or use the same science lab as the white students.

"The laboratory for the white boys was on the second floor next to the library," Dr. Massie recounted. "My laboratory was in the basement next to the rats. Separate but equal."

With the outbreak of World War II, he joined a special research team at Iowa State working on the Manhattan Project. In 1946, he received his doctorate.

Afterward, Dr. Massie began his enduring career in academia. He became a chemistry professor at Fisk but left after one year when he was named chairman of the chemistry department at Langston University in Oklahoma. He returned to Fisk in 1953, where one of his students was Marion Barry, who became Washington's mayor.

While at Fisk, he continued his research of phenothiazine, which was used in treating psychiatric disorders and in cancer therapy, and wrote a landmark article on the subject. From 1963 to 1966, Dr. Massie was president of what was then North Carolina College at Durham. President Lyndon B. Johnson then tapped him for a chemistry professorship at the U.S. Naval Academy.

He remained at the academy for nearly 30 years until his retirement as a professor emeritus in 1993.

Jeffrey Fitzgerald, chairman of the Naval Academy's chemistry department, said Dr. Massie was modest about his accomplishments and was a mentor to students and junior faculty members.

Ever the advocate of education, Dr. Massie served as chairman of the Maryland Board for Community Colleges and chairman of the governor of Maryland's Science Advisory Council. Of the many honorary degrees he received, he took particular pleasure in the one from the University of Arkansas because its segregation policies had prevented his admission.

Among his honors, he was named one of the six best college chemistry professors in the United States in 1960. He received a Lifetime Achievement Award from a White House initiative in 1988 and the U.S. Naval Academy's Faculty Achievement Award in 1990. His portrait was hung in the National Academy of Sciences gallery in 1995.

In 2002, the U.S. Department of Energy sponsored the Dr. Samuel P. Massie Chairs of Excellence, a $14.7 million grant awarded to 10 universities to enhance "groundbreaking environmental research and the production of top-level graduates." In 2004, Prince George's County dedicated Samuel P. Massie Elementary School in Forestville in his honor.

Dr. Massie's autobiography, "Catalyst: The Autobiography of an American Chemist," written with Robert C. Hayden, was published in 2004.

He regularly attended St. Philip's Episcopal Church in Laurel for 35 years, serving as an usher for most of that time.

His wife of 57 years, Gloria Thompkins Massie, died in January.

Survivors include three sons, Herbert Massie and Samuel P. "Trei" Massie III, both of Laurel, and James Massie of Little Rock; six grandchildren; and a great-granddaughter.

"I'd like to be remembered as a teacher who cared," Dr. Massie once said, "as a man who tried to make a difference."

As a chemist, Samuel P. Massie Jr. worked on the Manhattan Project and on health-related studies.