332 A. M. Mayer—Researches in Acoustics. 
it must occur in the regular measure in which the fork is 
sounded. The following are the facts really observed. At first 
every time that the mouth of the box is open, the sound of the 
the hand. 
2. On the discovery of the fact that a sound even when pre" 
cannot obliterate the sensation of another sound lower than 
in pitch, 
tense sound higher (instead of lower) in pitch. In this pi 
when the ear decides that the sound of the (lower and aie 
tuning-fork is just extinguished, it is generally discovere 
