Treadmills are a definite necessity to the making of motion pictures for the purpose of obtaining intimate scenes of animated objects or persons working before moving backgrounds. The evolution of this type of equipment dales back to the very beginning of the industry. Due to the fact that noise was of no consequence, these earlier machines were simply and crudely constructed. The type generally used employed the ordinary conveyor-chain principle, utilizing web belts running over series of rollers. Other developments include the revolving disk type, not entirely desirable due to the variation of surface speed in relation to the distance from the center of the circle; the gravity unit motivated by the persons or animals walking or running on them, etc., etc. Inasmuch as these were generally operated in front of sky backings or moving panoramas, speed ranges obtainable by gear boxes or belt pulley or chain sprocket changes were adequate. With the advent of sound and a more general use of the transparency or process background the need of smoother, more flexible, silent mills was recognized. The problem was carefully considered by the engineering department of Paramount Pictures, Inc., and the unit recently developed by them embodies all the previously mentioned requisites and to date has operated satisfactorily under the most trying conditions. — Construction details, speeds, degrees of silence, and other factors are covered in the paper.