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 
DE, H I, and an outer piece B C, K L, each of these 
L } 
three pieces being capable of separate rotation. This 
arrangement was kindly devised for me by Mr. Francis 
Galton. 
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 
cup containing larve on the table at B, and put an ant on 
