Efficiency Methods
An Introduction to Scientific Management

TIME-STUDY AND MOTION-STUDY 89 Just as in machine motion ordinary friction must be eliminated to the greatest possible extent, so all little frets and hindrances, and awkwardnesses that clog human motion must be smoothed away as far as possible, if there is to be no waste of energy. Mr. Gilbreth has perfected designs for reproducing small and rapid motions with almost incredible accuracy. In one method a small electric light is fixed to the moving hand or tool, and a photograph is taken of the path described. In Illustration I. the motions of the head, hand, and end of the club of a champion golf-player are reproduced. By placing an interrupt or in the electric circuit an intermittent line of light is obtained which will give the time of the motion, and can be arranged so as to give its direction also. Wire models can be made of this kind of photograph. A second way is to use a kinematograph, with stereoscopic adjustment and taking forty-eight pic- tures a second, to record the successive attitudes of an operator’s whole body. Time is recorded by including in the photograph a clock showing hun- dredths of a minute, and distance by a background marked in squares, which need not be behind the operator, but may occupy any plane in the picture if previously photographed. The motions taken by these means can be shown to workers at a slow rate as model operations. A point that is very remark- able in the photographed motions of an expert of any kind is the precision with which they are repeated, the successive curves being often