1904.] NATURAL SCIENCES OF PHILADELPHIA. 643 



As sources for air vibrations we used a piano, a violin,, and a Gallon 

 whistle. The keys of the piano gave us a range from 27 to 4176 vibra- 

 tions per second. The Galton whistle had a range from about 10,000 

 to about 60,000 vibrations per second, and was provided with a mova- 

 ble threaded core whereby any intermediate vibration could be ob- 

 tained. The range from the highest note of the piano, 4,176, to the 

 lowest one of the whistle, about 10,000, was bridged over b)^ vibrations 

 obtained from the violin. Thus a series of vibrations from 27 to 60,000 

 per second were available for experimental purposes. 



In testing the ants with these vibrations the artificial nests were so 

 arranged that their air was in free communication with the outer air 

 in which the vibrations were produced, but this was carried out in such 

 a way that draughts, to which ants are very sensitive, could not enter 

 the nests. The nests were placed upon thick paper, so as to isolate 

 them from vibrations that might reach them through the table upon 

 which they rested. The observer then closely watched a quiescent 

 ant under a hand magnifier, while a second person at several metres dis- 

 tance produced the vibrations as desired. As a rule, each key of the 

 piano was struck ten times in slow succession. If the ant under obser- 

 vation seemed to respond, it was given a resting period, and then re- 

 tested at the pitch to which it apparently reacted. The range of the 

 whistle, 10,000 to 60,000 vibrations, was divided into sixty intervals, 

 and these were treated as the keys of the piano, each note being blown 

 ten times while an ant was under observation. Ants were also watched 

 while the pitch of the whistle was gradually changed by slowly screwing 

 the core either in or out. A gradual change of pitch was also 

 produced on the violin. 



All the species mentioned as tested by us were subjected to this 

 range, 27 to 60,000 vibrations per second, and in no single instance 

 was any unquestionable reaction observed. Now and then an ant 

 would seem to respond to a given note, but in every case repetitions 

 of the experiment gave a negative result. We, therefore, conclude 

 that aerial vibrations between 27 and 60,000 per second give rise to 

 no observable responses -in the ants we worked upon, and as these 

 included representatives of three subfamilies of the Formicidffi, it is 

 highl}^ probable that a like condition will be found among other ants. 



Our results, then, agree Avith those of Hubcr, Ferris, Forel and Lub- 

 bock, but are opposed to what is stated by Weld and by Metcalf. In 

 one instance we worked upon the same species as Weld, namely, 

 Cremastogaster lineolata, and tested it with a note approximately that 

 used by Weld (4,096 vibrations), but obtained from the piano and from 



