Candid photograph of Johnson at approximately 50 years old at his desk.

Candid photograph of Forbush at approximately 65 years old talking in his office.

Candid photograph of Humphrey at approximately 50 years old, demonstrating the use of stimulus generator on a subject.

Candid photograph of McElroy paying three boys for their fireflies.

Candid photograph of Spitzer at approximately 65 years old smoking a cigarette in his study.

Candid photograph of Gopel at approximately 35 years old, working on maps with D.F. Bayly Pike.

Candid photograph of a girl chasing fireflies in a grassy, wooded area. The photograph has a caption that reads "From behind a tree, Mary spies another flash. She creeps upon it carefully."

Candid photograph of McElroy working in a lab. The photograph has a caption on the back that reads "Solution is again evaporated and put on second column, which takes more impurities from luciferin."

Candid photograph of Trefethen at approximately 35 years oak and Billingsle, who is approximately 30 years old in an office.