A. M. Mayer— Researches in Acoustics. 95 
be able to confirm my surmises by actual experiments on the 
effects of sonorous vibrations on the antennal fibrille ; also, the 
well known observations of Hensen encouraged me to seek in 
whose functions are the counterpart of those of the apparatus 
- theorem, and similar to the supposed functions of the rods of 
the organ of Corti. 
The beautiful structure of the plumose antennz of the male 
Culex Musquito is well known to all microscopists; and these 
organs at once recurred to meas suitable objects on which to be- 
in my experiments. The antenne of these insects are twelve- 
jointed and from éach joint radiates a whorl of fibrils, and the 
latter gradually decrease in their lengths as we proceed from 
those of the second joint from the base of the antenna to those 
of the second joint from the tip. These fibrils are highly elas- 
tic and so slender that their lengths are over three hundred 
times their diameters. They taper slightly, so that their diam- 
eter at the base is to the diameter near the tip as 3 to 2. 
I cemented a live male mosquito with shellac to a glass slide 
and brought to bear on various fibrils a 1th objective. I then 
sounded successively, near the stage of the microscope, a series 
of tuning-forks with the openings of their resonant boxes 
turned toward the fibrils. On my first trials with an Ut, 
fork, of 512 v. per sec., I was delighted with the results of the 
experiments, for I saw certain of the fibrils enter into vigorous 
vibration, while others remained comparatively at rest. 
he table of experiments which I have given is characteris- 
tic of all of the many series which I have made. In the first 
column (A) I have given the notes of the forks in the French 
notation, which Kénig stamps upon his forks. In the second 
(B) are the amplitudes of the vibrations of the end of the fibril 
in divisions of the micrometer scale; and in column (C) are 
the values of these divisions in fractions of a millimeter. 
A. B. C. 
Ut, ‘5 div. ‘0042 mm. 
Ut, 2°5 0200 
Mi, 1°75 0147 
Sol, 2°0 ‘0168 
Ut, 6°0 0504 
Mi, 15 0126 
Sol, 1°5 0126 
B- 15 “0126 
Ut, 2-0 0168 
The superior effect of the vibrations of the Ut, fork on the 
fibril is marked, but thinking that the differences in the ob- 
