New-York tribune., 1874-07-22
north-south movement of the latter appears to US
in the greater part of its course among the fixed

north-south movement of the latter appears to
IN the greater part of its course among the fixed
stars.
vERIFICArIoS or PREDICTIONS.
On June II The TRIBUNE published the first Of a
long Of communications respecting this comet
On that occasion there was little more gwen than
a congratulation to Prot Swift of Rochester for his
rediscoyery Of this comet, and estimate that it
would be near the earth about the first of
August On the sd of June a calculation based on
new observation, gave the elements, of the comet
which havo since proved to be surprisingly
accurate l. was then stated that the
periheion passage would take place on the
Sth Of July AZ 4 distance from the of GOOO0OOO
miles. The subsequent of the comet near the
Twins and down in Argo Navis also correctly
fore'old well as its date of greatest brightness.
July l6. L may here be mentioned that the cdlcu-
lation ou~wch these predictions founded. we're
verified afterWard by the report of observations
made by Prof ). X. Hind: the computations agree
ing 70 a very ct9se decimal fraction and proving
their substantial accuracy beyond all doubt. On
June ~ The TRIBUNE published the first OF the
communications relating - the tail Of the comet
ana ITS near approach TO the earth. FROM
day % day those computations were extended and
compared with She actual appearance of the comets
tail In respect 80 position ad extent, the sail fully
met expectations but its brightness scarcely equaied
the hope Of the observer The ciose approach 0f the
tail 70 the earth. ard the fact chat we missed lts
outer edge by less than two days notion III spaee, Is
yrt fresh i'm the minds Of readers. As the dovei
Opnent OF comets tails the rate of taeH motion, AMI
their curvature. have Oily been very recently SUBJ
jected 20 mathematical analysis this successful AZ
tempt at predicting the place and changes in the
tail Of Cocgils comet-the first instance IN which
anything of the sort has been attempted-ls highly
creditible 70 American astronomy.
FACTS AsCERTAISED 81 CALCULATION
On June > the observed length Of the tail was
computed as 100000 miles, on July l, 100000
miles; July 10. l2.O)OOO0 miles-an increase AFTER
the first OF that month of one-tweifth per dav The
tail continued from its first appearance till the head
Of the comet ceased to be visible, TO point from the
latter directly toward the stars Beta and Gamma of
the Lesser Bear Afterward il moved slowly to the
westward. so that IL covered the dipper Of che
Creator Bear The speed of the PARTICLES leaving
the head TO form the tail estimated as over
3.OO0OOO miles per day This brings the PARTICLES
leaving the comet on July 10 a distance from us
head on July p of about 25 100000 miles, correspond
ing at the latter date with the distance of the head
of the comet from the earth. But, though the tai
thus sweeps over sufficient space 20 cover the inter
val between the nucleus and the earth. the direction
Of the tail is such that 1t fails to reach US; ITS CEN
tra line being distant about 4OO)OOO miles, and the
edge Of the tal about 100000 miles from the EARTH
The orbit Of the comet was inclined 10 the ecptic
at an angle Of Gj to the equator Of 81 Its near
est approach 20 the was nearly two-thlrds that
OF the earth, and about one-fourteenth less thaA
that of Venus rate Of motion per day at ITS peri
heon was 100000 miles, that Of the earth beng
1550OOO miles. It's nucleus was estimated IN July
By Prof Hind. to be only 1000 miles in diameter.
On the basis Of the suns distance from the earth
being q. .0OJ.J00 miles the following data are COM
Duted: