1. Photograph of the two sons of Carl Bohnen Collection: Early 20th Century Engineering Lantern Slides Set: H. I. M. (Human Interaction Management) Date: undated Format: Image Agent: unknown
2. Effect of noise vs. quiet on the ability to work. The woman typist is wearing a mask under quiet and noisy conditions ; her breath is monitored by a man who is taking notes. Collection: Early 20th Century Engineering Lantern Slides Set: H. I. M. (Human Interaction Management) Date: undated Format: Image Agent: unknown
