left to right: French physicist and engineer R. Adrienne Weill (b. 1903) and John Phillip Nielsen (b. 1911). Nielsen, head of the metallurgical laboratory at New York University's College of Engineering, is shown demonstrating a dilatometer to the visiting scientist. Weill, a student of Marie Curie's, had been evacuated to England during World War II. While working at Cambridge University, the physicist had become a friend and mentor to Rosalind Franklin and then later helped Franklin secure a position at a prestigious French laboratory to further her skills in x-ray crystallography