A. M. Mayer— Researches in Acoustics. 331 
The general result of the numerous experiments thus made 
shows that the sensation of the watch-tick is obliterated by a 
coincident tick of the clock, when the intensity of the clock-tick 
must be regarded as merely approximative, not only from the 
manner in which it was obtained, but from the complenity of the 
sounds on which the experiments were made. It is interesting, 
perimenting with musical sounds. At the outset I will remove 
an objection always made by those versed 
unacquainted with these new phenomena. It is as follows :— 
‘You say that one sound may obliterate the sensation of 
sounded forcibly, and at a few feet from it is placed the mstru- 
ment emitting the sound to be obliterated, which may be either 
4 tuning-fork on its resonance box, or a closed organ-pipe com- 
ihunicating with a separate bellows. Suppose that in the fol- 
owing experiment both tuning-fork and closed organ-pipe Pr>- 
duce a note higher in pitch than the more ‘ntense or extinguish- 
ing sound of the open organ-pipe. Now sound the fork — 
pareniel y 
o% sound emitted b i his change cannot occur 
y the open pipe, this ¢ ng 
xcept when the fork is soandet and hence, if it occurs at all, 
