This deficiency, however, is remedied by another development in chronophotography. This is the continuous cinematographic record, the outstanding feature of which is the elimination of the revolving shutter and the intermittent movement of the film, in favour of a lens that is constantly open, a sensitized ribbon that moves steadily and continuously all the time the experiment is in progress.
Marey, in the course of his momentous investigations with animated photography, used this system for a number of experiments in which an intermittent exposure would not have afforded sufficiently precise results. Recent experiments have substantiated Marey's contentions upon this point, and have shown how unreliable are the results obtained with sixteen pictures per second where extraordinary precision is required. An effort was made to remove the drawback of the intermittent method by writing in, or divining, the movement which occurred during the periods of eclipse, but this method, in turn, was found to be unreliable. There are some motions which it is impossible to imagine or anticipate, even if they do occur in the one-thirty-second or one-sixty-fourth part of a second.
By courtesy of the Marey Institute.
Continuous Moving-picture Records of the Beats and Sounds of the Heart.
Electro-cardiogramme of a normal person. The upper line refers to the heart beats; the lower line is a photographic record of the heart sounds. These wonderful pictures are rendered possible by Dr. Einthoven's string galvanometer in conjunction with Mr. Lucien Bull's ingenious camera.
By courtesy of the Marey Institute.
Continuous Moving-pictures of the Heart Beats of an Excited Person.
The upper line shows the palpitations occurring at irregular intervals, while the lower line is a cinematographic record of the heart sounds.