New-York tribune., 1841-12-03

miles less than that of our planet. he surface oi
Venus Is extremely splendid, for the sun shines
upon 1t win great psver and II L sen 10 great ad
vantage Il mas therefore, bscu subjected 10 close
examination BY the astronomers OF modern uHes.
BY wajchin. II carefully =Pots Will be seen TO aP-
pear az one edge, cross lts disc ard disappear
rising again after an internal as observation vii!
show) of twenty four hours. Thus have VIZ found
two neighbors-two sister planets. having the same
vicissitudes OF day and night with me Earth Venus
presents the same appearance WIKI Mercury, OF
phases and for the same reasons.
Orlooking ciosely At Venus !; wlll De seen thsi
the inner edge OF the crescent she presents does
not terminate. suddenly. a. does tha- of Mercury;
but Is gradually shaded of from the splendsr ct
solar illumination To absolute darkness and opaci-
~ VIVA: Is tais bat the same thins which occurs
on our Ear,h L NOT the approach OF darkness
after sunset slow and gradual We find then that
Veau, has twilight as we'll as we. but OF longer
duration than ours y cur twilight; caused by
the reflection Of the Suns ravs after he has set by
the air. so d. we learn that Venu. mas atmos-
phcrs den.er than ours for her twilight Is longer
than ours. Venus too mas the vicis,itudes OF the
Seasons for :; ! found oy watching tha cour'e
of the spots upon her face that her axis i Inclined
10 the plane o.. her orbit q; an angle Of - while
that Of the Earth IS Only %. Her seasons are
therefore vf greater varet ana intensity Than ours
The mountains upon her surface, too. ara higher
than Uus: the highest mea-ured ! four times a
high a any on the Earth. The relative distances
Of Venus and the Earth from the Sun are repre-
senjed by and 10. - that the dIameterS OF the
Sun as seen from Venus and the Earth would be
10 and /. \ diagram Illustrating this point was
here exhibited
You have then visible cvi3caces of the minis;ra-
ton OF the great source OF ight aad heat TO these
bodies OF tie Solar System. Another question
arises in considering the fitness Of the planets Tor
habitati0n more material than those already ynotlced
for these are questions OF convenience. wh IN the
other the verv fact of existence Is involved. As
have already stated the weights OF bodies depend
upon no quality inherent in them but upon the at
traction OF the Earth. T-eref1rc we must tell
how heavy woulj we be at Mercury or Mt Venus
This j. easily answered. DR.. L. here repeated
the mode OF determining the weight of a planet
already given in a former Lecture. BY the mote
now described wr find that q body upon VI rcury
would weigh three fourth, as much on th- Earth,
while on Venus IL weight would be the same.
One other circumstance may be mentioned az an
interesting auecdoie in Astronomy. When Venus
passes betweca the Earth and Sun her orb comes
between the eve of the observer and the Sun
disc. II Will then appear like black spot ira
versing the face of the Sun, and inl> Is phenon-
cnon OF vast importance. In the middle OF the
last century there was young man who gave his
life to the study ct Astronomy He was unknown
TO tho world and possessed high and well culti-
yated talents. His attention and study were fixed
upon method of predicting the precise iue when
such a transit would occur-u problem Of difficult
aud battling calculafos to great astronomers.
The young astronomer said nothing of MS disco
very. Yet he feared if his prediction should prove
true and he were the sole observer no one would
believe him and thus the great truth would be lost
TO the world. Wiih this feeling he wrote to nj
friend Crabtree. acquainting hin with his disco-
vsry, and asking hisi to make the necessary OBJ
servations at the same time with himself. Tic
transit OF Venus across the Sun was observed by
the TWO to the infinite delight OF both The dis
coycrer died year two after this, but not until
h. had published treatise entitled FsRWs IN Sole
Visa.
The remainder of this Lecture is IN type but is crowd
cd until o-Isorrow