The tail of the comet was near the earth, which passed through it on
this occasion
]
The train may have been fan-like, as in the case of the comet of 1861,
discovered on May 13, by Mr. John Tebbutt of Windsor, New South Wales,
already referred to in the chapter on “Comet-hunting as a Hobby.” In my
father’s book, _Mysteries of Time and Space_, he records as follows his
view of that comet in connection with the drawing here given:
“The first recorded observations (of the comet of 1861, in Europe)
were made on the evening of June 30, nineteen days after it had
passed its point of nearest approach to the sun. I remember well
observing it on the morning of July 2, 1861. For some reason I found
it impossible to sleep that morning, and getting up about three (the
exact hour I do not remember, but it must have been very early), I
saw in the east what looked at first like the rays of an aurora
borealis. But presently I noticed that these rays proceeded (unlike
those of the aurora) from a bright center, which had been hidden by
clouds when my observations began. I used at that time to keep a
four-inch telescope, mounted on a three-legged stand, in my bedroom.
This I had quickly ready for action (noting that the object, owing
to the approach of sunrise, was getting fainter every minute), and
turning it on the comet, I drew a picture of the nucleus and coma,
so closely resembling that which appeared a week or two later in the
_Illustrated London News_, that I might have supposed my picture had
been surreptitiously sent to the office of the _Illustrated_, had I
not found it resting just where I had put it in my scientific
portfolio.”
Returning to the discussion of Halley’s comet, it was seen on May 21, at
4.30 A.M., by Professor Evershed, (then director of the Kodaikanal
Observatory, Southern India), appearing no broader than on May 18, but
fainter. He described it as passing centrally through the square of
Pegasus, which was nearly filled with the faint light. The tail could be
traced, as before, right up to the Milky Way. The star ε Pegasi was
nearly in the center of the band of light, and the star α Aquilæ near
its southern edge. This was the last observation Professor Evershed made
before dawn. He considered it remarkable that the tail of the comet
should have remained visible in the morning sky as a narrow band of
light, nearly two days after the head of the comet had passed to the
other side of the sun. He suggested that this might be due to the fact
that the tail may have been strongly curved and very broad in the
direction of the comet’s motion, although narrow and straight in the
direction at right angles thereto. If so, the passage of the earth
through the tail, if it occurred at all, must have been delayed one or
two days and probably occupied more time than a single day. There is
some doubt whether the tail did actually touch the earth, for
observations of its position in the sky on May 11 and 15 show that its
axis was inclined very considerably northward from the direction of the
radius vector, a straight line drawn from the nucleus of the comet to
the sun of the comet.
In the forenoon of May 19 certain peculiarities observed suggested that
our planet may have been actually immersed in the cometary débris of the
train of Halley’s comet. These consisted of a peculiar iridescence and
unnatural appearance of the clouds near the sun, and a bar of prismatic
colors on the clouds in the south. This, combined with the general
effect of the sky and clouds—for the entire sky had a most unnatural and
wild look—would have attracted marked attention at any other time than
when one was looking, as on this occasion, for something out of the
ordinary. According to the observations made by Professor Barnard at the
Yerkes Observatory, the sky had been watched carefully during the
forenoon of this date, but nothing unusual had appeared until close to
noon, when the conditions became abnormal. Later on in June, and for at
least a year afterward, slowly moving strips and masses of luminous haze
were observed in the sky, which were not confined to any one part.
Reports of like unusual phenomena were received from the Transvaal, and
from elsewhere in southern climes.
On the evening of May 21 the comet made its first appearance in the
west, as seen by watchers on the _Times_ tower, but it failed to be very
impressive. It was to the left and a few degrees north of the star
Betelgeuse in the constellation of Orion, and it resembled a star of the
third magnitude. It was surrounded by a hazy cloud-like mist that made
it appear nearly as large as the space covered by the moon. To the left
of it, and extending outward about three or four degrees, were three or
four fan-like streamers. At 8.25 the nucleus seemed brighter and more
star-like in the center, but the streamers had faded from view and the
mist surrounding the nucleus had become hazy and ill-defined. Five
minutes later only the star-like nucleus could be seen, doubtless owing
to the combination of the glare of moonlight and the haze that reflected
the city lights below.
On May 24 the comet appeared hovering for a brief interval over the
western horizon, resembling a faint star enveloped in mist, and adorned
with a short fan-like tail. On May 25 the comet could not be seen, owing
to the mist and a drizzling rain, but on May 26 it was visible on two
occasions for intervals of about five minutes. It then resembled a
fairly bright star of the third magnitude, surrounded by a misty halo,
but was devoid of a tail. It seemed that our chances of seeing the comet
again under favorable conditions were slight, but on the evening of May
27 we were once more regaled with a fine view, which proved to be final
as far as the writer was concerned.
At a few minutes past eight the nucleus of the comet appeared, as usual,
hazy and ill-defined, but gradually it brightened until it equaled the
glow of the first-magnitude star Regulus, in the constellation of Leo
near by. Only a few degrees of tail were visible at first, but as the
twilight deepened into night more and more came into view. By 8.40 P.M.
it stretched outward about twenty degrees in the direction of the planet
Jupiter. The train was long and slender, and not more than five degrees
at its greatest width. By 9 o’clock it was clearly visible, a dark
streak apparently dividing it just beyond the nucleus; the edges were
more or less sharply defined for a distance of about three or four
degrees. By 10.30 the train of the comet had almost faded from view; at
10.40 it had become invisible and the nucleus was barely perceptible.
Within three minutes the nucleus was almost lost to sight in the haze
and mist near the horizon.
Meanwhile, the moon had risen in the eastern sky, and by eleven o’clock
it was several degrees above the horizon. Its arrival on the scene was
the climax of an evening rich in glory, as far as the celestial display
was concerned. The view of the comet on this occasion was the best that
had been obtained since May 20, and settled beyond doubt the vexed
question that had arisen as to whether the comet had lost its tail or
had divided in two. Nevertheless, a glance at a photograph taken by
Professor Barnard on June 6, shows an apparently smaller comet nestling
to the left of the larger, keeping it company, as it were, in its
celestial voyage outward from the neighborhood of the sun. By this time
the comet had faded sadly, as Professor Barnard expressed it, and,
though a noticeable object, was only the ghost of its former self.
[Illustration: