New-York tribune., 1874-07-23

portion OF the matter endowed with repuson at least
twice that OF the rest Of the matter forming the tail AZ
water takes forms and powers. under different
dtons Of heat, first ice then water then steam. aud
then disscciated into Its constituent eementsso 1t
IL the cometary matter took different forms,
endowed with different repulsiye powers.
The cause OF the expansion of the tail remains also
known II 1t were due wholly part to the resist
Of the ether OF the celestial spaces the tail would
De extended in the plane Of the comets orbit; and the
tail OF n comet directly approaching should appear
narrower and brighter than when turned oblquey. No
such facts have been established in regard to the tale OF
Cogga's comet. and yet there observations which
seem to point directly that conclusion Will add that
the theory that the tail OF comet expanded chiefly in
the plane its orbit being nearly fat instead o. conical
in FORM furnishes satisfactory explanation OF the dark
line in the center Whether the tails OF comets vary in
apparent width in different positions, as this theory
would require. may perhaps be easily determined
II the theory of repusive force is true, It leads to
important results. When a particle starts in hyper
bOlic orbit away from the sum- in consequence OF
peling force its fate is sealed II must fly of beyond
the confines of system and into the sphere OF attac
ton of other suns Even the reconyerson OF the repu-
sion into attraction would be of avail TO stay its
course after it has acquired greater velocity than
that OF parabOc comet at the same distance from the
And so, cometary matter from other suns acting
under the law would necessarily at times visit u.s.
The existence OF repelling force suggested by
the fact that comets tail pointing eastward when the
comet is east of the SUM- points northward and west
ward the comet itself moves around to the north ana
west of the Yet. there Is conference In the
tall 1t is evident that repellng force from tho sum-
when to the east OF sun, have any tendency
bring around the west Of the sum- Tho TACT Is that
the tail which to be TO the west OF the sun Is
COMPOSED of entirely different matter from that which
was seen 10 the east The former matter has been re-
PEELED far from the sum- and has been so EXPANDED
that become nvisible and new matter has been
repeed from the nucleus forming new tail upon the
western side. The law OF repulsion will not only ac-
count this for the formation of tail at the
OF miles per day, recorded in the case
of the Of 1850 and lS43 The magnitude OF the
comets tail in those instances stupendous; but
Its velocity was no less astounding IL
commenced TO move at the rate OF $4,000 900 miles per
day; but unlike the motion of comet ITSELF the motion
is accelerated long the repelling force continues
to operate. There retardng force, as in the motion
OF q receding comet Whatever velocity has once been
reached is retained and the particles constantly
ceivng acceeratng force from the time they leave
head Of the comet although the amount OF the ac-
celebrating force which they receive will gradually di-
minsh the distance from the sun increases There Is
known instance OF comet coming into our system
with velocity approaching this; and as the tail of
chiefly formed after it has passed It's perhoon
when each successive addition TO the tail is impeled
with less velocity than that which started before it.
there be alternative to the theory that the
matter forming comets tail is thoroughly dfused
space that it can never be reunited
Ne,C York, July q, 1874. HENRY VI. PARIXiIURsI.
RECENT OBSERVATIONS on THE1CoMETs TAIL.
TO the Editor OF The Tribune.
SIR: Please allow me to verify the statement
of H. NJ Parkhurst and Prof Swift in todays TRIBUNE
saw the comets tail the evenings OF July 1S and 10,
from Patten's Hil Amesbury, Mass. through small
glass. At a point above line drawn from Zeta Ursa to
| Thuban it much resembled faint Zodacal beam the
lower portion plainly visible to the naked eye evident
length, ESQ., slight visible; time OF observation,
1910 and 1880 O'Clock H.; north sky clear. L. H. e.
NetcIOrk, July q, 1874