DR.. Lardner's Third Lecture.
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Let us now pass to the mex; plaust-Nars. No
other planet has 60 distinct features as this. Sir
John Hersche states that he saw distinctly and
repeatedly the spots on the surface occasionally
concealed. but when they were visible they were
always the same This was evidently caused BY
cloud. on the planet which occasionally obscure
the face Of the planer. BY the same process as
used in case OF the other planets We learn that
Mars has also day OF FL hours. and seasor.- al
most Identical witt those enjoyed by the sla5it-
ants et the Earth. \ part OF lbe surface OF 9la :
about oue-third,) has green color Tnr rest Is
slightly brown Sir Jehn Hersche mad no doub;
land indeed there be noue.) that the greeni-h
portion Is water While the brown Is land.


There Is another interesting circumstance re-
ating TO Mars, to which ask your close attention
| Near the pole of the planet mav be white
space, whicb Is observed 10 disappear when the
axis of Mars Is turned toward the Sun, and 10 re-
| appear on The return of winter. This closely
watched By Herschel, who found that when ii first
became visible it intensely white. During The
| six months OF summer 1t became gradually less
- hte and finally became brown like the rect Need
tell you what this white spot Is Nothing Bat
he P0iar iSR0icS OF Mars. While IL winter II
lccumuates and shines with intense splendor un-
der the Sun, in the sumner it melts away and
leaves ground bare and brswn like tie rest. Were
there no other proof tnat Mars had an atm ospAere
this would be sufficient, for every mejeorologi-t
knows that uir Is necessary to tho production o.
snow.


The redaes, OF Mars Is ascribed TO Herschell
10 the character OF it, soil which he ssppeses J.
similar to our red sand stone others attribute it
to the density OF lis atmosp phere-just II, the Sun
appears red to Us when rising setting.


The magnitude OF the Sun Mars is less
rhan when the Earth, and the heat and
light enjoyed there are proPortionably less.


.jupiter j. the next planet in the order OF he
Solar system (Between Mar, and Jupiter Is a
cha-m, IN which have been discovered fragments,
Of broken planet which filed the deficiency
and completed the analogy discovered by keper
and Others. Deterring the consideration OF these
fragments until come to treat OF Comets, shall
oyerleup this chasn and pass to Jupter.) This
planet OF extraordinary magslJude it. diameter
being $4,000 miles, and I;s magnitude 40
greater than thar ot the Earth. This stupendous
body is easily examined from It's great siz-. ln
cooking al portrait Of Jupiter, the >treaks across
It's face ara at Observed their p 'cuiiar posi-
ton Is also matter of surprise they always being
parallel 10 each other


By watching the permanent marks on Jupiiers
disc find that il Ievovcs It's axis III hours.
which is therefore, the length OF its day. Here
IS a tact whicE takes Jupiter out of the class Of the
naneis. The fist four have DAYS OF = hour, each
then eaping the chasn We hnd planet with day
Of only ten hours. The distance OF Jupiter from
the San is 100000 900 Of miles; the Suns dunn
from that planet Is but one fifth OF that
seen from the Earth, while It's apparent magnitude
is twenty FIVE times less. This is wise provision
of Providence that while the inhabitants have so
little light and heat they are deprived of it but for
Iit,I. ti,pa The avis ot Iunifsr inclined the
plane OF its orbit Only one degree, that this pla
net has no seasons and its days and nights arc OF
equal length 1t must bs difficult for the rhabi
tants of Jupiter to keep an account of time, and
they must have very scientific among them t~
10 it by tracing the progress of the Sun through
the Stars here we do it by he seasons.


The belts Of Jupiter are curious objects OF specu-
lation, but they may he easily accounted tor. We
are all acq lainted with the trade-windS, produced
by the action OF h- Sun the Equator combined
with the motion of the Earth on It's axis. Were
the Sun always in the Equator Instead Of the
Ecptic, and were the motion of the Earth swiier
than il Is the TWO causes would be more decided
in their effect, and the clouds would be arranged
in belts parallel TO the Equator. But on Jupiter.
as it has no seasons, the Sun IS always IN the
Equator the planet with diameter 20 much
greater than that of the Earth revolves in less
than half the time. Therefore dc the clouds
arrange themselves in belts


The Satellites of Jupiter shall discuss whec
| come to speak of the Moon There remains
but one planct-SdtvrR and as full consldera-
ton OF tins body would consume more Tins than
remain. thi. evening, shall postpone it 10 Il fu-
lure occasion. Dr. Lardner concluded by an
nouacing hat the subject Of the lecture on Satur-
day evening will he the Comets


