The New York herald., 1879-12-11
METEORS AND ASTRONO OMERS-PARK.
HURST AND PROCTOR.

To THE EDITOR OF THE HERALD:-
The meteors which wore seen last Sunday evsy1ng
d not belong to the Andromed revolving around
the sun in the orbit Of Biela's comet, but seem to
have been chiefly Geminids although two Of
them were probably Aurigids, both OF which series
of meteors appear within few days of the 7th OF
December. and generally few in number but
bright. For several days to come there may be me-
from either of these series. but they
much scattered in space that there is proba-
bility of their taking the form OF q shower.
AS the period of Biela's comet six years and
eight months the earth did not pass this year very
near the point through which passed in the
shower Of 1872. We shall be ut about the same dis
tance in 1885, but shall then be ahead Of the shower
instead of being behind it, as this year.
But in 1892 the earth will pass very nearly through
the same point as in 1872. that there will be .
greater probability OF brilliant display that year
than at any time preceding.
In the letter of Professor Proctor. published in
the HERALD of the 9th inst, he swept away the ap-
parent difference between U.S. that there is but
single point left and upon that the mode reason
ing which he indicates is far conclusive that per-
haps might properly yield tho point without fur
thcr comment. 1 certainly have no rcsson 10 feel
very much mortified to bo found In tho company OF
those whom Professor Proctor has proven to be
mistaken in the discussion OF such subjects. But
the phenomenon in question is too Interesting In
its nature to be dismissed In that way. With your
permission. them will follow out the argument In
my own way little further than he has done. Tho
the thickness OF the train the less the proba
bity OF the meteoric train becoming visible, but
the shortness OF the time the Andromedes are visible.
being confined perhaps exclusively to single day.
instead OF being extended over weeks as In the case
of some other series of meteors. the Gemipids and
Aurigids for instance, indicates that the train
Is not yet much -scattcrod. Assuming. then. for
convenience in first letter. tho thickness OF
the train to be only 10000 miles although the por.
will be likely be too much difused to DO visible,
the portion beyond that distance will appear more
aud more luminous with increase of distance, and
may possibly DO by contrasting IL with the sky
o degree more distant from the centre OF lumin-
osity But even with this slender train the distance
must be more than 7.OVOO00 miles before tho circle
becomes less than ono-sixth OF the diameter Of
the moon and within that distance IL will DO large
enough to be seen by the naked eye, and as mag
nifying power can make IL brighter telescope
can make 1t more visible. IL In necessary then, In
take into consideration portions OF the train
than 7.OOO00W miles distant from This suggosta
the question or tho curvature OF the orbit
which might DO neglected for short dis.
tances. From q hasty computation mako the
radius OF curvature tho comets orbit at the point
of junction with the earth's orbit little two
hundred million miles, that IL the train be viewed
exactly end ut the Distance OF ,7,OO0O0O miles,
the deviation will be about one degree, and instead
OF the nebulous body visible to the naked eye being
circular the nucleus would be degree one side oi
the centre, and still! further II the train is long
enough for the telescope bo useful in its obsorva
tion. Just before the earth reaches the orbit this
curvature doubles upon ITSELF excepting that the
orbit of the earth Is inclined to that OF the eteor
the returning portion OF the visible train would not
lap the other part but be above it. II then the
meteors should be bright enough to DO seen at all
the form aud appearance OF the nebulosity would
enable us to to the actual length OF the
train and its position In the orbit, that future
returns could bo predicted. And tho same general
Rnown orbits. HENRY M. PARKMuRsr.
BnooKLrN. Dec. 10, 1879.