118 ILLINOIS ACADEMY OF SCIENCE 



this manner was gradually increased in successive series, 

 until all twenty lights were in operation. In all cases 

 the length of the flash was the same but the intervals be- 

 tween the flashes varied from .5 sec. to 2.5 sec. in .5 sec. 

 increments. The temporal distribution of all the lights 

 was such that only two out of the twenty could flash at 

 the same instant. 



In a final series we tried the effect of continuing a 

 rhythmical grouping that was given four times at the 

 beginning of the series, but passing thence into the ut- 

 most irregularity of flashing. 



Results. It was curious to see the emotional effect 

 of all of our series on the observers. Some of it un- 

 doubtedly was due to the appearance of these odd and 

 silent flashings on the wall of a dark-room. But more 

 curious still were the spontaneous associations with fire- 

 flies. Some of the remarks, as made by different ob- 

 servers, follows : 



''Impression of lightning bugs flitting." 



''Idea of lightning bugs." 



"I had the idea that I was watching fireflies at night or 

 butterflies flitting about." 



"Lightning bugs on a warm night." 



"Fireflies in summer." 



These statements suggested to the writer that the ap- 

 paratus which served to isolate the natural conditions on 

 a small scale in the laboratory had not taken away the 

 essential significance of the experiment by carrying the 

 abstraction too far. The fireflies were psychologically 

 there. 



But more important is the result derived from nearly 

 every series and from every observer showing the strong 

 tendency to organize the experience into patterns or 

 groups. Sometimes it was a spatial pattern which re- 

 minded one of the several sets of trees or shrubs which 

 in the narratives were illuminated in turn, for frequently 

 the introspective reports would reveal a visual arrange- 

 ment Avhich was superimposed mentally on the experience 

 as it came. As one observer put it, "an indistinct im- 

 pression of a pattern that recurs and yet cannot be de- 



