108 A, M. Mayer— Researches in Acoustics. 
them directly through the membrana Reissneri from the scala 
vestibuli; and furthermore, the shielding influence of the mem- 
brana tector tends to prevent this direct action on the cords. 
If my view be correct, that these cords receive their vibrations 
from the faa membrane, and not directly from the impulses 
sent into the ductus, it t necessarily follows that these cords bear 
to the membrane, to they are attached, the same rela- 
tion as stretched pata beer to the vibrating tuning-forks in 
Melde’s experiments ; and, therefore, a cord in the ductus will 
vibrate only half as often in a second as the basilar membrane to 
which it is fastened. Hxperiments, similar to those described in 
brate the basilar membrane, the only hair-cell cords which 
enter into vibration are those in tune with the elementary vi- 
brations existing in the membrane. Also, it is to be observ 
that as the loaded string makes one vibration to two of the 
membrane, so the hair-cell cord makes only one vibration to 
two of the basilar membrane 
If it be true that when single vibrations impinge on the ear, 
the tympanic and basilar membranes vibrate twice, while the 
co-vibrating body only vibrates once, then it follows that if the 
same simple vibrations can be sent directly to the co-vibrating 
sake of the ear, without the intervention of the basilar mem- 
rane, we should perceive a sound which is the octave of the 
ear through the bones of the head; and although we cannot 
prevent the simultaneons vibration of the tympanic and basilar 
membranes, yet we can at the same time directly vibrate all the 
parts of the mnerear. Therefore, if we first hold this fork near 
the ear and note its pitch and the quality of its sound, and then 
press its foot firmly against the temporal bone, we should per- 
ceive a marked difference in the timbre of the fork when 
sounded in these two different positions; for when its foot is 
Ss De sr 1 RNa CN nS a eer 
