, 1881-08-07
THE NEW COMET.
Its Apparent Path Among the
Stars During August.
4 Word About Mathematical OyerreacIi.
ings-Xilat Comets Are
Made or.

The comet which suddenly flashed into our
view on the morning of June y; has nearly
left us. 1t has gone from the gaze of the
many, thousl, still visible Il little below tho
"suards" in Ursa minor, If one looks sharp
Is for it with the naked eye. 1t is nearly
time for the comet enthusiast to 'off with
the old love and on with the new.' The
one discovered July Is, by SchT5cre, is now
i'll such 4 position among the stars that it is
above our horizon, i'll the northwest, after
shutdown, antl is SO much nearer to us than
when first seen that it would be easily
"pickel mp if the moon were absent In
the latter part Of the coming week the moon
will not rise till after dark, and the comet
may then be easily seen. 1t will not, how
ever, be ut any tiineSo bright rs the one now
fading out from our view. as an ail to those
who may wish to find it, VIC present the
accompanying map of its apparent course
among the stars durin. the present month.
Only the places OF the more prominent stars
are shown OIL the diagram. On the upper
right are the two head stars III Ge1nini,
known rs Castor and Polux. The Great
Bear occupies the top Of the map, the we'll
known Dipper" beng in the left part Of
the figure. South from the Bear is Leo, the
t'Sickle part of which is also i well-known
group. To the right from Leo are the Bee
hive Nebula, and its companion stars, the
!Ase1l; while on the left of Leo are the stars
in the head and girdle OF Virgo. The curved
line represents the apparent path of the
comet, its course being from right to left
The comet entered last Wednesday upon the
region embraced by the map. To-nightitwil
be north from Castor a week hence it will
TaIita, the last-named star being in the fore
paws of the Bear. On the 18th the comet
will be due south from the wcll-knOWn
"pointers in the Dipper. On the :s.tt it
will be south from Denebola, on the 18th
south from, Gamma Virgins; and Sept. !
nearly south from Arctnrus, the last-named
star being outside the limits Of our diagram.
The comet will cross the equator about Sept.
2, and thence pass, nearly due sOuthWaru,
out of sight 1t will he brightest about Aug
~, being then nearest to the earth.
This comet was first seen near the place III
which the June comet maue its debut before
us, and is now not far from the place where
Coggia's comet seemed to hang il space for
cidence' do not, however, prove identity.
The positions are not the same with
respect to the sun. Even If the earth
be ut the same point in her orbit OH the two
occasions, the fact OF seeing two comets III
line with Il given star does not prove that
they are one and the same; while it the earth
be not ut the same point in her orbit the ll,-
parent identity of position is Il pretty. good
reason for believing that the two are distinct
objects. The three comets here referred to
are certainly not one and the same. The
identification of ut least ono of them with 4
comet observed several years previously is
unfortunately larupercd by what we may call
the cotnputcr's lnania, which leads him to
than is warranted by the conditions of the
problem. 1t is a grand thing to be able to
compute the orbit Of Il comet from three OBJ
seEvations; but i is Il still higher attainment
to be able to tell how nearly such a comp.-
tation can be depended on Indeed, siia lat
ter belongs to the highest branch Of mathe-
NAUTICAL reasoning, as it isalso especially mod
ern; and possibly requires the greatest
amount Of courage us well as discrimination.
1t is far from being impossible that the comet
Of last June is the same thatappearetl III lS01,
rs the latest may prove to be one that ap-
pearcu in 1872.
The comets of this year, though numer-
ols, can scarcely be said to have eadded much
servations may show how easy it IS for prac-
ticed observers and computers to obtain un-
trustworthy results both in observation andin
computation. The comets have been observed
by tile aid Of the spectEoscopc; but that IN
strument has told us nothing more than what
We knew previously, the GASEOUS en-
yeiope is probably some form of il hydrocar-
bon, while the nucleus proper may be more
nearly like what Sir w. Thompson called a
"clond Of stones" and the tail u veritabfe
gaseous appclldage. The indisputable fact
that each particle lit the tail moyes; III obedi-
ence to the law Of attraction Of gEavitatior
etfcctually tlisposes of the nor-mathenIaticaf
theories of reflection by the ether, rtfractiOn
through the COMA, etc. If VIC cal, conceive
4 multitude Of pebbles separated by Spaces
comparable with those between the atoms Of
terrestrial masses, while all move as unit
mass around the sun, we shall probably have
as good IN idea Of tile nucleus Of the comet
rs could be conveyed BY several hours of
description. Similarly, II we tan conceive
locomotive is expanded 50 as to make it oc-
cupy a space Il Thousand millions times
greater, without all increase in the quantity
1T matter, We shall probably have rs good an
idea IF the tail Of the comet as is at present
attainable.