A pendulum sets off stimuli by contacts in the path of its swing, and carries a sheet of sensitive paper past the recording beam of light which is focussed on the paper through a cylindrical lens. On the photographic records appear abscissae produced by shadows of a grid of silk threads on the lens, time ordinates .01" apart produced by interrupting the light beam with the toothed armature of a synchronous motor, and stimulus and reaction lines produced either by deflections of additional light rays or by shadows. A photograph of the recorder is included, together with sample records of lid reflex, knee jerk, and word reactions. The recorder has the advantages of practical noiselessness, adaptability to time measurements varying from .0001" to 1", economy in respect to time of operation, laboratory space, and record material. (PsycINFO Database Record (c) 2006 APA, all rights reserved)