iv.] UNKNOWN SENSES. 125 



making them hear me, I endeavoured to ascertain 

 whether they could hear one another. 



To ascertain if possible whether ants have the 'power 

 of summoning one another by sound, I tried the follow- 

 ing experiments. I put out on the board where one of 

 my nests of Lasius flavus was usually fed, six small 

 pillars of wood about an inch and a half high, and on 

 one of them I put some honey. A number of ants were 

 wandering about on the board itself in search of food, 

 and the nest itself was immediately above, and about 12 

 inches from the board. I then put three ants to the 

 honey, and when each had sufficiently fed I imprisoned 

 her and put another ; thus always keeping three ants at 

 the honey, but not allowing them to go home. If then 

 they could summon their friends by sound, there ought 

 soon to be many ants at the honey. The results were as 

 follows : 



Sebtember 8th. Began at 11 A.M. Up to 3 o'clock 

 only seven ants found their way to the honey, while 

 about as many ran up the other pillars. The arrival of 

 these seven, therefore, was not more than would natu- 

 rally result from the numbers running about close by. 

 At 3, I allowed the ants then on the honey to return 

 home. The result was that from 3.6, when the first went 

 home, to 3.30, eleven came ; from 3.30 to 4, no less than 

 forty- three. Thus in four hours only seven came, while 

 it was obvious that many would have wished to come 

 if they had known about the honey, because in the next 

 three-quarters of an hour, when they were informed of it, 

 fifty-four came. 



On the 10th September I tried the same again, keep- 

 ing as before three ants on the honey, but not allowing 



