The weekly Louisianian., 1874-07-18
The Louis1anial.
COGGIA'S COMET

COGGA'S COMET.
Professor Henry N. Parkhust, in
his second letter to the New York
Tribune has the following comfort
ing statement to make respecting
the monsters tail:
Since writing my communication
in the Tribune Of July 4, I have sat
is6ed myself that the delay OF the
comet,s tail from curvature will be
about four days, during which time
the earth will have moved SO far
that no probable errors of eomputa-
ton or ,ef estimation would bring
US within it. Having settled that
7 shall introduce, IN illustra-
ton which otherwise might have
been too suggestive Of danger: A.
tall man, having an India rubber
club. two feet long, and three inches
in diameter at the end, sees a spider
running very rapidly across the ia:
BILE. He raises his club alcft at
arms length; and brings it down
with q terrific blow. He aims for a
point two feet in advance Of the spi-
DEF, allow for its motion, and strikes
very nearly the point which the
spider would have reached when
the club struck the table,; but in
consequence Of the club bending a
little more than he anticipated, the
spider escapes by one inch. This
is an approximate representation, on
q small scale, of Whist takes place
within the next three weeks, with
two exceptions. In the first place
the club, insted Of being Of rubber.
is of such attenuated material that
if the spider were hit he would not
know it; and secondly, an. ordinary
spider would be many thousand
times too large to represent the
earth. Perhaps I should add q
third, that the size Of the club is only
known from estimates, since it may
increase in thickness during the
blow.
On July 8. I estimated the length
of the tail of the comet to be 70 30,
but the end. of it was 80 faint that
many persons saw it not much more
than half that distance. On July
s. I estimated the length to be 12o,
and company Of persons with ne
varied in their estimate from 12o to
40 by comparison with stars known
to me, and one, "by the aid Of a
little Imagination" could see it for
a length of 14a. Taking my own
estimates, the tail had increased in
length six per cent within these two
days, although part of this may be
due to the unnoticed haze in the at
mosphere on the third.
The brightness OF the comet on
the third and fourth indicates that
it will have an equality on July IA
with the star Altar, the brightest
star, with three exceptions, visible
in tho evening with it. AS Donati's
comet equaled Arcturus in bright
ness, I am by no means confident
that the present will be equally
bright.
The motion of the earth is $780,
600 miles per day; thatof the comet
about 100000 per day. and will
continue about the same so long as
it remains visible. The motion OF
that part of the tail nearest us is
nearly 100000 miles per day; that
is, seventy per second, which is 5000
times faster than the motion of an
express train. The thickness of the
tail I assume at about 100000
miles at the distance of 10000, 600
miles from the head, when it shall
have reached that length. If the
earth were to pass centrally through
it the passage would occupy
about twenty-four hours. Passing
through the extreme edge, as I at
81 A- -.-lY~ -~s1l n~k