The Ottawa free trader. [volume] (Ottawa, Ill.) 1843-1916, 1845-04-25
SCIENCE.

The following extracts from the inaugural ad-
dress of Prof. J. MARI, delivered on ire III OF
January before the Mechanics Institute of New
York, we copy from the Evening Pos, and On.
dofse the editors ,cmalk that readers will not
find it 100 long.
mention these facts, only in the hope
of showing you tina. there is pleasure in
studying the sciences, and when we come
. TO Natural History we shall find The STU
dy of that still more amusing. The ami
mai and vegetable worlds are we'll worthy
of observation. Probably you all know
what is meant by cycioM. If we make
spot on the periphery Of wheel, trav-
cling on plane, the figure which that
spot describes is cycloid. Now, there
is no figure in which a body can be NOV
ed with SO much" velocity and such regu.
larity Of speed, not even the straight line.
Malhematicians discovered this not many
years ago; but Natures God taught it 10
the eagle before mathematics were inven-
ted; and when the eagle pounces upon
his prey, he describes the figure of cy-
cloid.
A globe placed in wafer, or in air, in
moving meets with resistance, and its We
lociIy will be retarded. If you alter the
globe to the form of an egg, there will
be less resistance. And then there is
form called the sold Of !fast resistance,
which malhemalicians studied many years
to discover, and when they had discover
cd il, they found they had the form of
6sh's head Nature had 'rigged out"
the fish with just such a ligue.
The feathers Of birds, and each parlic-
ular part of them are arranged in such an
angle as to be most efficient in assisting
flght.-The human eye has mirror, on
which objects are reflected, and nerve
by which these. reflections are conveyed
TO the brain; and thus we are enabled to
take an interest in the objects which pass
before the eye,-Now, when the eye is
too convex, we use one kind Of glasses
10 correct the fault, and if il be not con-
vex enough, or if we wish to look at OBJ
jects at different distance, we use glass
es of entirely another description.
But as birds cannot get spectaces,
Providence has given them method Of
supplying The deficiency. They have
the power Of contracting the eye, of ma
king it more convex, so as to see The
speks which float in the atmosphere, and
catch them for food; and also of nallen.
ing the eye, 10 see 10 great distance,
and observe whether any vullure or other
enemy is threatening 10 destroy them.
In addition 10 this they have a film, or
coating, which can be suddenly thrown
down over the eye to protcc, it; because
at the velocity with which they fly, and
with the delicate texture Of their eve, the
least speck of dust would act upon ii as a
penknife thrust into the human eye
This film is to protect The eye, and the
same thing exists 10 some extent, in the
eye of the horse. The horse has large
eye, very liable 10 take dust. This coat.
ing in the horses eye, is called the haze,
or third eye.lid, and il you will watch
closely, you may see i, descend and re.
turn with electric velocity. 1t clears
away the dust and protects the eye from
injury. II the eye should catch cold, the
haw hardens and projects, and ignorant
persons cut i. of. and thus destroy his
safeguard.
You all know, If you take pound of
iron make it rod foot long, what