58 Royal Society :— 
Experiment 3.—A vibrating tuning-fork C’ was placed at one ex- 
tremity of the angular piece of wood, the other extremity being held 
between the teeth; the fork was at first heard very distinctly, and 
when its sound could no longer be distinguished,.the straight piece 
was substituted, and it was again heard for the space of two 
seconds. 
Experiment 4.—Instead of the horizontal portion of wood. repre- 
senting the stapes, three portions of the same size were made into 
a triangle, and this was glued to the anterior surface of the inferior 
extremity of the piece representing the incus, thus f mat The 
previous experiment was then repeated with the substitution of this 
apparatus for the angular one, and with nearly the same result, viz. 
the fork was heard through the straight piece about three seconds 
after it had ceased to be heard by the apparatus representing the 
chain of bones. 2 
Experiment 5.—A piece of very thin paper was gummed over the 
end of a glass tube 6 inches in diameter; to the outer surface of 
this paper was glued a model of the chain of ossicles similar to the 
one used in the previous experiment; a vibrating tuning-fork C’ 
being placed in the interior of the tube and within a quarter of an 
inch of the paper, the sound was heard through the free end of the 
chain placed between the teeth for ten seconds; when the sound 
ceased to be heard, a straight piece of wood was substituted, and the 
sound was not heard through it. 
Il. Experiments illustrative of the influence of the articulations 
in the chain. 
Experiment 1.—Three pieces of wood, each about 5 inches 
long and half an inch in thickness, were separated from each other 
by pieces of india-rubber as thick as ordinary writing-paper, and they 
were then fastened together so as to assume the angular form pos- 
sessed by the chain of ossicles. The tuning-fork C’ being placed at the 
free extremity of the chain, the other extremity being held between 
the teeth, it was found that the sound was heard as distinctly and 
for the same length of time, as when it passed through the chain 
formed of three portions glued together. 
Experiment 2.—When eight layers of the india-rubber were placed 
between each piece of wood, there was still very little difference in 
the intensity of the sound from that observed when it passed through 
the portions glued together. 
Experiment 3.—One, two, or three fingers having been placed 
between the first and second pieces of wood, and eight layers of 
india-rubber between the second and third, a very slight diminution 
in the intensity and duration of the sound was observed as compared 
with its passage through similar pieces when glued together. 
Experiment 4.—The back of the hand was placed in contact with 
the teeth, and the end of the vibrating fork C’ was pressed against 
the palm; the sound was heard very distinctly for several seconds ; 
and when it ceased to be heard, a piece of solid wood 3 inches 
