The Middlebury register. [volume] (Middlebury, Vt.) 1850-1882, 1877-10-26
Mars.

When Calico turned toward Mars
the telescope with which he had discov-
cred the moons of Jupiter, the crescent
form of Venus, and many other Won
dcrs in the heavens, he was altogether
disappointed. His telescope was in
deed too small to show any features of
interest in Mars, though the planet of
war is much nearer to us than Jupiter.
Mars is but a small world. The Diane
ter of the planet is about 400 miles,
that of our earth being nearly 5000. Ju-
pitcr. though much farther away, has
his immense diameter of more than S0,-
600 miles to make up, and much more
than make up, for the effect of distance.
With his noble system of moons he ap-
pears remarkable object, even with q
small telescope, but Mars shows fewer
features of interest. even with tclc-
scopes of considerable size.
Ii was not, then, till very powerful
telescopes had been constructed, that
astronomers learned what we now
know about Mars.
1t is found that his surface is divided
into land and water, like the surface of
our own earth. But his seas and oceans
are not nearly so large compared with
his continents and lands. You know
that on our own earth the water covers
So much larger surface than the land
that the great continents are in reality
islands. Europe, Asia and Africa to-
gcther form one great island; North
and South America another, not quite
so large; then come Australia, Green
land, Madagascar, &C., all the lands be-
ing islands, larger or smaller. On the
other hand, except the Caspian Sea and
the Sea of Aral, there are no large seas
entirely land-bound. In the case of
Mars very different state of things
prevails, as you will see from the three
accompanying pictures (hithcrto un-
publishcd, drawn by the famous Eng
lish observer, Dawes (callcd the Eagle
cycO. The third and best was drawn
with telescope constructed by your
famous optician, Alvan Clark, of Cam
bridge, Massachusetts. The dark parts
are the seas, the light parts being land,
or in some cases clouds or snow. But
in these pictures most of the lighter
portions represent land; for they have
been seen often so shaped, whereas
clouds, of course, would change in
shape.
The planet Mars, like our earth, turns
on its axis, SO that ii has day and night
as we have. The length of its day is
not very different from that of our own
day. Our earth turns once on its axis
in-but before reading on, try to
complete this sentence for Yourself. Ev-
cry one knows that the carth's turning
on its axis produces day and night, and
nine persons out of ten, if asked how
long the earth takes in turning round
her axis, will answer, a hours: and il
asked how many times she turns on hcl
axis in year, will say 800 times. or, il
disposed to be very exact, ''about
365 IA times" But neither answer i
correct. The earth turns on her axis
about 3G6 ii times in each year, and
each turning occupies 23 hours SO min
utes and 4 LILO seconds. We, taking
the ordinary day as the time of n turn
ing or rotation, lose count of one rOta
ton each year. 1t is necessary to men
ton this, in order that when tell yor
how long the day of Mars is, you may
be able correctly to compare it will
our own day. Mars, then, turns on hi!
axis in "A hours, 81 minutes and % III
seconds. So that Mars requires Al min
utcs and Is Clio seconds longer to turn
his small body once round than on
earth requires TO turn round her mucl
larger body. The common day of Mar
is, however, only about 80 minute
longer than our common day.
Mars has n long year, taking no les
than 6S7 of our days to complete his cir
cult round the sun, so that his yea
lasts only about one month and hal
less than two of ours.
Like the earth. Mars has seasons, fo
his polar axis, like that of the earth, i
aslant, and at one part of his year bring
his northern regions more fully int,
sunlight, at which time summer pre-
walls there and winter in his southern
regions; when at the opposite part o
his year his southern regions are turn
ed more fully sunward and have thci
summer, while winter prevails over hi
northern regions.
Around his poles, as around tn
earth's, there are great masses of ice
insomnch that il is very doubtful whctll
or any inhabitants of Mars have bccl
able to penetrate TO his poles, any NOR
than Kane, or Hayes, or Mares, or Par
ry, despite their courage and cndur
ance, have been able to reach OUr north
crn pole, or Cook, or Wilkes, or Jane
Ross, our antarctic pole.
In the summer of either hemispher
of Mars, the north polar SHOWS bccom
greatly reduced in extent, as is natural
while in winter they reach to low lati
tudcs, showing that in parts of the plan
ct corresponding to the United State
or mid-Enrope rs TO latitude, bitter col
must prevail for several weeks in sue
ccssiOn.-f Prof. II. A. Proctor. ~