The Ottawa free trader. [volume] (Ottawa, Ill.) 1843-1916, 1855-11-17

We copy the following interesting chap
ter, perhaps, from the pen of Prof De WE'RE,
from PgtRaD.'s Koathiy for November:


ter, perhaps, from the pen of Prof. De WE'RE
from PgtRdm's KOnthiy for November:
Audubon has written an amusing book,
had almost said of fables, called Drnitholog-
ical Biography. by a number of cruel cx.
pcrimrnts, he has proved to his own entire
satisfaction, and that of many others, that
vultures are led TO their food by the sense Of
sight alone the sense Of smell, which they
were supposed to possess ia an exquisite de-
gree, ailOrdng them not the slightest assist
ancc. His experiments prove quite too much
for his purpose, for they equally deprive the
poor bird in question of both sight and
smell 1t is certain that this bird possesses
both senses in great perfection, and equally
certain that neither nor both are the sole
means it employs for obtaining its food
Though the senses in animals are means Of
obtaining them food, they are not the sole
means, as we very well know.
1t is a most curious question, and well
worth more attention than it has yet re-
ceived. For want of better explanation,
we usually say there is an instinct that ena-
bles animals to find their food. Many 20
from great distances directly to it. Pigeons
find out ncwlysown fields Immediately, and
will frequently 90 several miles to field the
very first morning after it is sown. Wild
ducks that feed at night, are equally quick
in finding their food and in this case, |
would be glad to know what sense they en-
ploy The red-decr invariably knows when
the shepherds patch Of grain is fit for his
food, and will frequently come down in such
numbers as to eat up the entire crop in a
gip,ln ,i,lt In T,,t al l.trIy ,,I,a
their food may be- have an instructive power
of discovering it immediately, and that from
such distances as no aCutCncss Of either sight
or smell will account for. Without allowing
this, you cannot explain facts too numerous
aud too well authenticated, to be doubted
1t is precisely the same faculty, whatever it
may be, that enables the carrier. pigeon to
find its way home, take It what distance,
and any way covered up, you will. Toss it
up in the air, and, after cjrcling for n few
moments it adopts its line Of flight, without
hesitation aud without mistake. Audubon
himself furnishes an instance Of the exercise
Of this faculty, in his description Of the ra-
zorbllI. "Ihc instinct or sagacty which en-
ables the razorbiIs, after being scattered ia
all directions in quest Of food, during tho
long night, often at great distances from each
other, TO congrcgate towards morning, pre-.
yiou,ly 10 their alighting on a spot to rest,
has appeared to me truly wonderful and
have been tempted to believe that their place
of rendezvous had been agreed upon the
evening before
In diSputing about the comparative value
Of the senses Of sight and smell IN birds,
authors notice much more curious fact
the great power birds possess Of altering the
focal length Of their eyes. 70 see equally
well an object at distance Of many miles,
and minute seed or insect an inch from the
bill, may well amaze Us Observe the first
person Of your acquaintance you meet, who
happens to wear spcctaclcs II hc looks at
an object near him, he looks Mroyyi bis
glasses; if at more distant one, occr them.
Go to practical optciau and desire him to
construct an instrument that will enable you
to do what birds are constantly doing in
this, and he will, most likely, tell you the
thing Is impossible,
Man probably surpasscs birds in extent Of
vision, Is much as birds surpaSs man ia
sharpness. KoSS, IN his voyage to Balm S
Bay, proved that man, under favorable
circumstances, could see over the sea, 100
miles. 1t IS not probable that any animal
can equal this for extent. In sharpness Of
sight, on the other hand, birds greatly excel
us. The eagle, soaring at such height that
he seems Il mere speck, sees the grouse
walking in the heather, which it so closely
resembles IN color as readily to escape the
spor'sman,s eye. Schmidt threw to con
siderable distance from thrush number
Of beetles, OF pale gray color, which the
unassis'ed human eye failed to detect yet
the bird observed them Immediately Many
birds readily perceive insects on branches
where the sharpest sighted person can detect
nothing.
The eyes OF birds are remarkable for their
great comparative size, the great conyeXty
OF the cornea, and for having the sclerotc
coat formed anterloriy to circle OF bUny
plates. The optic nerves are very large,
and unite so intimately as to appear perfect.
ly incorporated. The iris is exceedingly
contractIe-as al may have observed who
have watched bird dying. Birds do not
expire with eyes open, AS is the case with
man and the lower animals and when they
are expiring, you may readily observe the
great power they possess Of dilating and
man. are six in numbcr-four STRAIGHT and
two obliaue. In many birds the eye.ball
POSSESSES very little nobility. and in some
Of the owls il is so closely fitted into the or.
L;t os 70 Lo ;,r,,oy,lIo