BIRDS AND ALL NATURE. 
Illustrated by COLOR PHOTOGRAPHY. 
Vol. IV. OCTOBER, 1898. No. 4. 
EARS. 
By W. E. Watt. 
I HE air is an elastic fluid sur- 
4 I rounding the earth. The 
qJ I motions of things whether 
alive or not, set it in a state 
of vibration that rarely ceases. At all 
times and in all places it is pulsing 
responsively to all that is going on. 
Animals are interested in what is 
moving about them. It may mean 
life or death, pleasure or agony, and 
most animals are keen to know which 
is for them at any given period. They 
are therefore equipped with organs 
that respond to these waves of the air. 
They are variously equipped, some 
hearing certain sounds feebly where 
others are acute to them and deeply 
moved. Some sounds are full of 
moment to one organism arousing it 
to nervous activity while another 
organism knows nothing of what is so 
distinctly heard by the first. 
Can a Mule hear more than a 
Mouse is a question which has agitated 
many young people who have con- 
sidered the length of the former's ear 
and its versatility. A series of experi- 
ments once conducted in youthful 
sport by the writer, seemed to settle 
the matter that each can hear sounds 
which are unnoticed by the other, and 
that the ear of the Mouse is much 
better adapted in hearing powers to 
the occupation of the Mouse than is 
that of his long eared neighbor. Cer- 
tain shrill sounds of whatever degree 
of loudness, cannot be heard by the 
Mule even when oats might be secured 
by attending to them, while distant 
sounds of a heavy character seem to 
fail to affect the ear of the Mouse. 
The same is noticeable in the hear- 
ing of people. To some persons a note 
one octave higher than the highest 
note of a piano, cannot be heard. 
Others can hear such a tone, and yet 
others are made painfully nervous by 
it without knowing quite what the 
trouble is. To some the chirp of the 
Sparrow is the upper limit of hearing, 
others can hear the voice of the Bat, 
yet others are able to hear the notes of 
insects that range higher in pitch 
than the voice of the Bat. Dr. Wollas- 
ton says, " As there is nothing in the 
nature of the atmosphere to prevent 
the existence of vibrations incompar- 
ably more frequent than any of which 
we are conscious, we may imagine 
that animals like the Grilli (Grass- 
hoppers) whose powers appear to 
commence nearly where ours term- 
inate, may have the faculty of hearing 
still sharper sounds which we do not 
know to exist ; and that there may be 
other insects, hearing nothing in 
common with us, but endowed with a 
power of exciting, and a sense which 
perceives vibrations of the same nature, 
indeed, as those which constitute our 
ordinary sounds, but so remote that 
the animals who perceive them may be 
12 
1 
