16 ^ 
Dr 'Wollaston on Sounds 
that commonly occurs in hedges during a summer’s evening, 
which I believe to be that of the gryllus campestris. 
I have reason to think, that a sister of the person last alluded 
to had the same peculiarity of hearing, although neither of 
them were in any degree deaf to common sounds. 
The next case which came to my knowledge was in some de- 
gree more remarkable, in as much as the deafness in all proba- 
bility extended a note or two lower than in the first instance. 
This information is derived from two ladies of my acquaintance, 
who agree that their father could never hear the chirping of the 
common house-sparrow. This is the lowest limit to acute hear- 
ing that I have met with, and I believe it to be extremely rare. 
Deafness even to the chirping of the house-cricket, which is se- 
veral notes higher, is not common. Inability to hear the pierc- 
ing squeak of the bat seems not very rare, as I have met with 
several instances of persons not aware of such a sound. The 
chirping which I suppose to be that of the gryllus campestris, 
appears to be rather higher than that of the bat, and according- 
ly will approach the limit of a greater number of ears ; for, as 
far as I am yet able to estimate, human hearing in general exr 
tends but a few notes above this pitch. I cannot, however, 
measure these sounds with precision ; for it is difficult to make 
a pipe to sound such notes, and still more difficult to appreciate 
the degree of their acuteness. 
The chirping of the sparrow will vary somewhat in its pitch, 
but seems to be about four octaves above E in the middle of the 
piano-forte. 
The note of the bat may be stated at a full octave higher than 
the sparrow, and I believe that some insects may reach as far as 
one octave more ; for there are sounds decidedly higher than 
that of a small pipe one-fourth of an inch in length, which can- 
not be far from six octaves above the middle E. irBut since this 
pipe is at the limit of my own hearing, I cannot judge how 
much the note to which I allude might exceed it in acuteness, as 
my knowledge of the existence of this sound is derived wholly 
from some youiig friends who were present, and heard a chirp- 
ing, when I was not aware of any sound. I suppose it to have 
been the cry of some species of gryllus, and I imagine it to dif. 
