MOVEMENT 



CHAPTER I 



TIME 



Its Graphic Record ; Time-measurement by means 

 of Photography 



Summary. — Graphic record of time— Chronograph}- — Rudiments of 

 the method — Transmission of movement to the recording needle 

 which registers the duration — Chronographic record of a man's 

 foot in walking, during the phases of rest and motion — The same 

 of the four feet of a horse in its various jiaces — Record of the 

 fingering of a pianist--Applicalions of photography to the regis- 

 tration of time — Measurement of the exposure allowed by a photo- 

 graphic shutter — Measurement of the time intervals between 

 successive exposures. 



Graphic Record of Time. — Time, like other magni- 

 tudes, can be represented in a graphic form by straight 

 lines of various lengths. In this way the respective 

 duration of several events can be gauged by the 

 various lengths of parallel straight lines placed side by 

 side. The order of commencement of these phenomena 

 can be expressed by the relative positions of the begin- 

 nings of the straight lines. With regard to the exact 

 order and duration of the events, they can be indicated 

 bv means of a scale, subdivided into divisions which 



