The Nevada Democrat., 1859-11-30
WHOLE NO. 321.
New Groups OF Asteroids.

The recent discovery of a new group Of as
tetoids is so remarkable an instance of the pre-
csion Of astronomical observation and the pow
er OF mathematical genius, that il is worthy of
more than passing note This discovery was
even Of greater difficulty than that ofNeptune.
For that he had only to study the perturbations
of Uranus, to ascertain in what, the orbit of
Uranus differed from what II should be theoret-
ically, aud to deduce from this difference the
perturbing cause. The perturbatons of Uranus
had been definitely ascertained before he took
hold of the problem. But the perturbations of
Mercury are his own discovery as well as the
brilliant result he has drawn from them.
Mr. Leverrier first found. by his own obser-
vations, commenced in lS42, an unexplained
movement of the perhelion of Mercury. This
he verified by q careful study Of all the obser-
vations on the passage of Mercury across the
disc Of the sun since 1897. After attempting to
refer this movement to oil known causes,
and to all possible inaccuracies Of obser-
vation, there still remained considerable
movement Of perhelion unaccounted for
Continuous experiments in varions drec-
tions led him to the discovery that by in
creasing the secular movement OF the perhelon
of Mercury by 3S seconds, all the observations
were reconcied to within second of an arc
quantity so small that il might safely be re-
ferred to errors of observation. This increase
of perhelion movement could by no means be
referred to the attraction of Venus. Venus
could produce this effect only IL her supposed
mass were increased by one-tenth. But this in
crease would alter the obliquity of her orbit to
the ecliptic two seconds and half The sup
position could not therefore be entertained.
NJ. Leverrier was therefore reduced to the
supposition of an interior planet, moving in an
orDit q little inclined to that Of Mercury. The
size of this planet might be greater or less, as
IL was at greater or less distance from Mer-
curry; alta distance of 20,o000o0 miles from
Mercury, II would be just about equal 10 Mer-
curry In mass. Here was the problem solved.
But how could such planet have remained so
long undiscovered Certainly it would have
been seen in some Of its many passages across
the disc of the sun. ''All these diffculties,"
says NJ. Leverrier, disappear upon the suppO-
stion OF q series of small bodies instead of
single planet, revolving between Mercury and
the SUM-" Their united attraction might pro.
duoe the movement observed in the perhelion
of that planet, and If they moved in circles they
would have no effect on the eccentricity of its
orbit.
Distributed through all parts of the ring
which they would form, each would neutralze
the periodic actions of the Others Nor is it
wonderful that they have not been discovered
by our telescopes. We have discovered only
Tue lhTBeT OF tue hSterOlus between MATS ana
Jupiter. and we suppose that the @rolites which
occasionally fall to the earth come from innu-
merable groups of small bodies which are trav-
cling in the orbit of the earth. Asteroids, then
may be large or small and the new group of as
teroids may be 20 small as to have eluded OBJ.
servation.
It is recorded that on tae 18th of June, l777,
Messer saw great number of black globules
crossing the disc Of the sun for about five min
utes This Is the only indication that the new
asteroids have ever been observed. The search
however,, which is about to DO instituted, will
be very thorough. In total eolipses of the sun,
the astronomer may, during the few minutes Of
totality, explore a great portion Of the region
around the sun indicated by NJ. Loverrier. The
next total eclipse will be 10 July, 1860. A pho
tographc re cord also, of the disc of the sun, IL
frequently made and long continued, cannot
fail soon to give occular vision of these young
est daughters of the universe, as yet seen only
by the eye of science, guided by the wonderful
genius Of n. Leverrer.-M y Tribune.