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THE POPULAR SCIENCE MONTHLY 



FURTHER STUDY OF INVOLUNTARY MOVEMENTS.* 



By JOSEPH JASTROW, Ph. I)., 



PROFESSOR OF EXPERIMENTAL AND COMPARATIVE PSYCHOLOGY IN THE UNIVERSITY OF 



WISCONSIN. 



IN a former article (Popular Science Monthly, April, 1892) vari- 

 ous illustrations were given of the involuntary movements of 

 the hand toward the object or locality to which the subject was 

 giving his attention : whether he were counting the strokes of a 

 metronome or the oscillations of a pendulum, reading colors or 



words, thinking of a building, locality, or 

 hidden object, a very fair though variable 

 index of the direction of his thoughts 

 could be derived from the involuntary 

 movements of the hand. The record was 

 obtained by means of an apparatus called 

 the automatograph, the essential parts of 

 which were a pair of glass plates, suitably 

 mounted, and between them three well- 

 turned brass balls ; the hand rests upon 

 the upper plate, which, upon the slightest 

 impulse, rolls upon the balls, and the move- 

 ment thus imparted to the plate is recorded. 

 The recording device may be used sepa- 

 rately, and is shown in full size in Fig. 1. 

 There is a cork C, pierced by a glass tube 

 T, within which a pointed glass rod R 

 moves freely up and down ; a rubber band 

 B is useful in raising the pencil from the 

 record as well as in preventing the rod 

 from falling through the tube. The record 

 is made upon a piece of glazed paper 

 stretched over the glass of a ground-glass 

 drawing-frame, such as children use for 

 tracing outlines ; the paper is blackened 

 with lamp-soot, and the record may be 

 made permanent by bathing it in shellac 

 and alcohol. This recording device, with- 

 out anything else, will record involuntary movements : the cork 

 is held in the extended hand with the rod over the record-plate, 

 which is placed upon a table ; or, again, the record-plate may 

 be held in the hand and the recording device held firmly over 



Fig. 1. Device for record- 

 ing Movements. The glass 

 rod, E, moves freely up and 

 down in the glass tube, T, 

 held in the cork, C. The 

 rubber band, B, prevents 

 the rod from falling through 

 the tube. 



* The results of this paper were obtained with the co-operation of Thomas P. ( 'niter and 

 Edward P. Sherry, of the class of 1892, University of Wisconsin. 



