High speed motion picture photography

A motion picture camera used in taking 4000 pictures per second is described. Applications of high speed motion picture photography to a variety of problems associated with the design of telephone apparatus are given. The resulting pictures in “slow motion” permit convenient and accurate analysis of space-time relationships of mechanical parts in motion otherwise too rapid to be perceived because of their transient nature. This work has related to the development of relays, switches, clutches, ringers, dials, coin collector mechanisms, contact conditions, materials testing, etc. It has been applied to studies of noise reduction in mechanisms and to research problems associated with the production of speech by the vocal cords.