He was the second African American to earn a Ph.D. in physics and the first in the 20th century. He was among the first known African-American scientists to make important contributions to modern physics ; others' prior work was unrecorded or uncredited. While working in industry, he gained four patents for instruments to be used for measuring magnetic and electric properties. As an academic, he developed and chaired the department of physics at Fisk University, serving from 1930 to 1941.