Evening star., 1924-07-06
Fifty Years Ago
In The Star

Half century ago a great comet
| approached the earth so nearly that
| much excitement prevailed
| A Great in this country in antici-
| patton of possible evil con-
| Couet' sequences to humanity. In
| The Star of July ., 1874, is reprinted
from the New York Tribune an article
| by Henry NJ Parkhurst, astronomer.
| giving an estimate OF the probable
closeness of this approach and the
possible effects. 1t was estimated
| that the comet would be visible to the
naked eye on that day and that by
| the goth it's tail would have become
so expanded in the neighborhood of
| the north pole as to fill a large part
| of the northern heavens. Prof. Park
hurst said:
"Of the way In which this will end
it is not safe yet to speak with def
niteness, for. although, if the tail
were straight, we should be almost
certainly near the middle of 1t on
July 20. yet its curvature will prob
ably delay it two or three days, and
even until the earth has passed be-
yond its path. Taking the best value
l can from the records of previous
comets, 1 should expect the earth on
July 22 to be wholly within the east
ern edge of the comets tail The
comet will then disappear to us, but
then the inhabitants of the southern
hemisphere, who may be ignorant of
the cause of the luminosity of the
evening sky, will see it gradually
rise and pass away and will be
amazed by the sudden apparition OF
a comet of extraordinary size and
unusual brilliancy, which will burst
upon their vision as unforeseen as
the great comet of 1861. The grad
ual diminution and final disappear
ance of the comet will be so nearly
the converse of what we shall have
had witnessed here that it needs no
description.
What will be the effect on the
earth? 1 dare not predict the effect
on the minds of men,
Effect on especially of the igno-
the World. rant; but do not antic-
physical effect further than possible
electrical phenomena like the aurora.
| 1t will, Of course, leave us a portion OF
its atmosphere when it departs, but
| probably not enough to affect the
| barometer or to come within the
| cognizance even of scientists. But
there may be by possibility one per-
| manent effect of scientific interest
and curiosity. If the earth should
not entirely escape the moon also
probably will be involved and 1t will also
| retain portion of the cometary sub
| stance. AS the amount of atmosphere
| upon the moons surface is now so
| SMALL If indeed there Is any at all,
hot to = a a hv ha
| incest astronomical scrutiny, perhaps
| after the passage of the comet we
! shall find that henceforth the moon
| will have an atmosphere, of greater
| or less density, which will materially
modify the phenomena Of occulta-
| tions and solar eclipses. l will add
that Venus is safely out of the way,
SO that the transit expedition will
not be interfered with by the great
comet of 1874"
In a second card from Prof. Park
hurst he said: Il have assumed that
the repulsive force is the same in
that upon Peirce's theory, with this
| assumption, a particle of matter Ieav-
Ing the head of the comet on June
9, when the tail was already 2 de-
grees in length. would on July 20 be
nearly 100000 miles outside the
earth's orbit. 1t is evident, therefore,
that the first requisite of a magnif-
cent display. length of tail. will not
Gle leaving the head of the comet
June % will also be on July 90 out
side of the orbit of the earth; but
that from the curvature of the tail
near the constellation Hercules. Since,
| therefore. the portion of the tail
nearest to US would be more than
two days behindhand in crossing the
ecliptic, 1t Is as yet somewhat doubt
full whether we shall be involved In
its operations