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Dead medium: Gilbreth's Chronocyclegraph, Part One
From: (Deac Rossell)

Source(s): *The Purpose & Practice of Motion Study* by Anne G. Shaw (Manchester & London, 1960: Columbine Press) pages 93-96

(((Dead Rossell remarks: Chronocyclegraphs were first developed by Frank B. Gilbreth, one of the pioneers of industrial time-and-motion studies in the 1910's.)))

"Gilbreth was the first to apply the analysis of the path of movement to solving industrial problems. He developed his technique without any knowledge of Marey's work and, when his attention was drawn to it as the result of correspondence with a friend in England, he felt that it would have helped him considerably if he had known of it earlier.

"His technique differed from Marey's in that instead of taking a series of photographs on one plate, he took a single photograph of lights placed on the operator's hands or on some other part of the body. He used a stereoscopic camera, opening the shutter at the beginning of the work cycle, and closing it at the end. This gave him a line graph in three dimensions when the result was viewed through a stereoscope.

"He was not satisfied with the information given by this 'cyclegraph' and continued his experiments until he had developed an apparatus which interrupted the light of the lamps at regular intervals, giving a graph made of rectangular spots, of a length varying according to the speed of the movement, and showing the acceleration and deceleration along its path.

"Finally, by re-arranging the interruption of the lights so that they came on quickly and went off slowly, he developed the chronocyclegraph as we know it, with its characteristic pear-shaped spot showing the direction of the movement.

"Gilbreth was still working on the development of the chronocyclegraph technique when he died in 1924. He had taken many successful chronocyclegraphs himself, but the method had not been sufficiently standardised for others to use it easily. He was planning to adapt his material so that it would be in a suitable form for teaching others, but unfortunately, in the inevitable rearrangements after his death, the apparatus was lost.(...)"

(((bruces remarks: Deac Rossell's most recent book is *Living Pictures: The Origins of the Movies* (Albany, 1998: SUNY Press). His new book covers developments in the magic lantern, chronophotography, the invention of celluloid, and early film inventors. )))

Deac Rossell (