ROTATING DISKS. 



263 



got used to this arrangement I waited till one was on 

 the disk (Fig. 25) and then gently drew it to the other 

 side of e, as shown in Fig. 26. In this case, however, 

 the ant did not turn round, but went on to g^ when she 

 seemed a good deal surprised at finding where she was. 

 In continuation of the preceding experiments I 

 constructed a circular table 18 inches in diameter 

 It consisted, as shown in Figs. 27 and 28, of three 

 concentric pieces — a central f G, an intermediate 

 D E, H I, and an outer piece B C, K L, each <rf these 



Fig. 27. 



three pieces being capable of separate rotation. This 

 arrangement was kindly devised for me by Mr. Francis 

 Gal ton. 



I then connected the table with a nest of Lasius 

 niger by a paper bridge a, and also made a paper path 

 across the table, as shown in Fig. 28, divided into five 

 pieces corresponding to the divisions of the table. 

 This I did because I found that the ants wandered less 

 if they were provided with a paper road than if they 

 walked actually on the wood itself. I then placed a 

 oup containing larvae on the table at B, and put an ant on 



