“By the death of Miss Leavitt on December 12, 1921, the Observatory lost an investigator of the highest value. She had obtained a comprehensive experience in photographic photometry, and had developed a clear appreciation of the difficulties involved in the theory and practice of this important research. Her work on standard magnitude sequences was nearly concluded at the time of her death, but she had hardly begun work on her extensive program of photographic measures of variable stars. In the foregoing summary no mention has been made of Miss Leavitt's work on standard photometry...”