318949.1306 There are a number of these chronocyclegraph studies of locomotion (at least 9), some of which are numbered 1700.152 (etc.) and some of which are numbered in the 18000 series, such as 18198. FBG took these as part of his shoe-fitting investigations in the military motion study laboratory. This particular image looks like it might document the movement of the knees in locomotion, since the light is a bit high up for feet; see the companion images to this one (at least Gilbreth image number 1700.153, 1700.156, and 1700.158; there may be others in the database).