534 



SCIENCE 



[N. S. Vol. XXXVII. No. 953 



tions, corresponding to auditory difference- 

 tones. In arousing these, the two fork stems 

 were firmly pressed together, and the circular 

 end of one stem pressed lightly against the 

 skin of the border of the palm; or the sub- 

 ject's finger tips were pressed lightly against 

 the fork stem. 



Fearing lest the phenomenon might be some 

 peculiarity of the action of the physical couple 

 corresponding to the " objective " difference 

 tone, certain auditory experiments were car- 

 ried out, as follows. A Konig resonator was 

 tuned to the difference tone of one of the 

 forks; it of course gave no response when the 

 vibrating forks were not in contact, and it 

 still gave no response when the stems were 

 pressed together. Pressing both stems against 

 a block of resonant wood failed to make the 

 resonator respond, although the wood was 

 brought within a few inches of the orifice of 

 the resonator. A single fork tuned to the 

 difference-tone and resonator, pressed against 

 the wood in this way, evoked a loud response 

 from the resonator, even when the fork was 

 vibrating feebly. 



It occurred to me that the point (in the 

 scale of rapidity) at which the beats passed 

 into a differential sensation might give a 

 measure of the lower limit of palmesthetic 

 sensibility, and that in any case the deter- 

 mination of this point was important. Here 

 the difficulties were encountered. 



As only an approximate determination was 

 desirable at this juncture, one of the c' forks 

 was scaled in the steps b, a#, a, g#, g, fS and 

 f, certified forks being at hand for these rates, 

 giving differences with the other c' fork of 

 16, 33 +, 42 +, 56, 64, 78 + and 85 + double 

 vibrations. 



In my own case, the determination is fairly 

 certain. The beats are distinctly perceptible 

 down to c'-g (64). At c'-f5 (78 +) this dis- 

 creteness begins to pass into a sensation com- 

 parable to that of another fork (i. e., a con- 

 tinuous sensation), and at c'-f (85+) this 

 new sensation becomes unmistakable and defi- 

 nite, the beats entirely disappearing. 



With still greater difference, the differen- 



tial sensation persists, becoming less and less 

 intense, as is the case with the sensations 

 aroused by single forks of increasingly higher 

 pitch. 



In the first day's work with W., a graduate 

 student, the results were exactly the same as 

 those obtained from myself and were invari- 

 able. A month later his results were radically 

 different. He still observed the differential 

 sensation as like that from a low fork, but 

 claimed that it was a matter of discrete 

 pulses, differing from the beats of smaller dif- 

 ferences only in rapidity. In fact, he now 

 claimed that the single-fork stimirii, even from 

 the 512 fork, gave series of discrete sensa- 

 tions, and further claimed that the auditory 

 stimulus from the same fork produced the 

 same sort of discrete sensations, correspond- 

 ing to the air pulses. It should be said that 

 W. is unmusical, but is a good observer. 



My own observations fit in quite well with 

 those of W., as regards the palmesthetic sen- 

 sations, although the auditory sensations (be- 

 yond 40 vibrations per second) are always sen- 

 sibly continuous. With best attention, the 

 palmesthetic sensation (beyond 85 per sec- 

 ond), is as continuous as the auditory, but 

 nevertheless at certain other times it seems to 

 be a discontinuous series. In my observa- 

 tions, however, there is a clear indication of 

 the reason for this discrepancy. In one case 

 I am attending to the sensation as it is; and 

 in the other case to the fork thought of as 

 an oscillating body — to the representation of 

 visual or muscular sort — rather than to the 

 actual presented sensation. Such training as 

 my palmesthetic sensibility has received dur- 

 ing the greater part of my life has probably 

 been in the way of interpreting the sensa- 

 tions in terms of the vibrations represented 

 as movements of some body; hence, even when 

 I should be attending to the sensation I still 

 incline to attend to the meaning instead. A 

 large number of individuals undoubtedly tend 

 to treat vibration in this way. 



In attending to sounds, the interpretative 

 tendency is not so strong, as the conditions 

 are not so conducive to training in this direc- 

 tion. The special significance of sounds as 



