Bristol news. [volume] (Bristol, Va. & Tenn.) 1867-189?, 1871-03-10

ger than our own. The inclination o
his axis to the plane of his orbit resem
bles that of the earth; so that his sea
sons are similar to ours, save in length
The martial year contains 6S7 days o
twenty-four hours, so that each season
lasts about five months and twenty
days. Owing to his greater distance
from The sun, however, Mars receives
only half as much solar light and heal
as the cath; but the extent to which
| this difference affects his climate can.
not be determined until we know more
about the density of his atmosphere
and the amount of aqueous vapor con.
tanned i'm it. But in the eccentricity o.
his orbit Mars differs at present consitl-
erabiy from the earth. Like the earth,
he has his perihelion in the winter oi
bis northern hemisphere; but while
the earth receives only about seven per
cent. more solar light and heat in JAN
uary than i'm July, Mars receives near
ly fifty per cert. more heat in perihe-
lion than in aphelion. Cool summers
and warm winters must reign in his
northern hemisphere, while south of
his equator the contrasts must be
greater than any to which the present
deRiZens of the earth are accustomed.
But the eccentricity of any planets
orbit is variable. Twice during the
last three million years-certainly,
therefore, since the appearance of the
higher mammals-the earth's orbit has
been very nearly as eccentric ss that
oI Mars is at present. At THESE periods
the climate of the earth appears to
have been seriously affected, and ex-
tensive migration Ofanimals an 1 plants
seem to have taken place. 1t is not
improbable that similar phenomena
may now be occurring on our neighbor
Planet.
The most striking point of difference
between Mars and the earth is one
which does not essentially affect the
production or the maintenance of or
game life. A man weighing $50 lbs.
on the earth would weigh but little
over 60 lbs. OH Mars, so inferior is the
gravitative force of the planet
where gravitation acts so feebly, all
engineering operations would he rem
dered much simpler; bridges could
have wider span and yet be stronger
than our terrestrial ones, buildings
could be loftier and yet be raised more
easily, and transit of all sorts would he
effected much more readily, while at
the same time the distances to be trav-
ersed are very much less than ON our
earth"
The other members of the solar sys-
lem which, according to the general
views here presented, have a claim 10
be regarded as inhabituble, are Mercu-
ry, Venus, the third and fourth satel-
lites of Jupiter, and the sixth satellite
of Saturn. In point of size these
moons rank with the primary planets,
the two JOyials being as large or lar
ger than Mercury, while the Saturnian
is considerably larger than Mars. Be
sides the advantage of starting with
prodigiOus stock of heat, they ha' e, if
Mr.. Proctor's views are correct, enjoy
ed the peculiar advantage of being
warmed by their su..-likc primaries.
If the tea in a tcacup is set in front of
blazing dire, il Will no cool 80 rapid
ly.
As far us it has been possible to ex-
anime Venus she appears tn be in size
and cOsmical relstions almost the ex-
act counterpart of EARTH; and if the
views here prOpOundcd are correct,
she cannot wildly differ from it in
physical constitution. She has an ex-
tcnsive atmosphere. in which Padre
Secchi claim. to have discovered nitro
gen and aqueous vRpor. She has also,
probably, masses of snow about her
poles. Mercury seems to have rath-
or dense atmosphere. and both planets
have mountains. But both thee plan
cts, situated near the sun, are difficult
to observe; and in the case of Mercu-
nv, we have not yet determined the in-
clination of the axis of rotation.
We have taken up SO much space
that we will not stop TO sum up the
details cf the argument. We had in
tenGe to examine Mr.. Proctor's views
&C ncerning comets and meteors. in
connection with tho theory of nebular
genesis, as well as to follow him into
the region of stellar astronomy. But
the comets and meteors must stand
over until the appearance OF Mr..
PructCr's new work on The sun. and
his relations to the planetary system.
And out of the vast mass OF revelant
facts which might be culled from side
real astronomy, We viii only cite re-
cent very satisfactory achievement OF
the spectrOscOpe. 1t is well known
that Sir w. Herschel was originally
Il d to the nchular hypothesis through
his study of the irresOlvable nebul&.
He supposed these nebui9 to be case
Gus condition as a proof OF his theory.
Since his time many of these nebuiR
having been resolved into starry clus-
tiers, il began to be suspected that.
wi h q sufficiently powe rful telescope,
it might be possible to resolve them
all: hence by some writers the nebu-
lar hyDothesis was thOughtlessly do
clared to have lost its chief support
as if the evidences furnished by the
structure of the solar system had
thereby lott their overwhelming force
For the benefit of those who have
been troubled by this perplexing doubt
il is well enough To state that the ques-
ton has been settled forever. Her
schel was right. There are nebulse
which no actual or possible telescope
will ever resolve. for the spectroscope
has proved that they are gaseous.
With this weignty argument, brought
in from tie remotest depths of stellar
space, we may fifty close. In spite of
all that has of necessity been omitted.
perhaps enough has been said tn illus
trate the superior clarness and cohe-
renee which is gained for the results
of studies like Mr.. Proctor's, when
they are based upon the grand theory
of nebular genius.
Trron the Scientific Americana