The diamond drill. (Crystal Falls, Iron County, Mich.) 1887-1996, 1891-07-18

THE STRANGE PLANET ARC
TURuS NOW VISIBLE.
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gress.

subject OF very interesting lecture by
Mr.. VIM. III. knight, recently delivered
before the Cincinnati Society of Natural
History. We give herewith few ex-
tracts from the paper:
Within the last two or three years a
new and surprising value has been
given % the parallax of Arcturus by
DIR. Elkin. the astronomer of Yale uni
versity. Previous To his work at Yale
he had acquired reputation for pains
taking observations and accurate re-
suits in the British observatory at the
Care OF Good Hope. Equipped with
: minute heliometer provided with the
latest improvements, he set himself the
task OF measuring the parallaX of sew
eral prominent stars. Devoting himself
{, Arcturus, from no less than 50
observations. taken in connection with
ten comparison stars, he deduced the
very small parallax Of $4,000 or about
l-56 OF "A second OF arc, which is equiv
alent 10 distance OF ls1 light years.
This minute parallax (which is assumed
10 be approximately correct by other
astronomersl, combined with it's large
proper motion, gives Arcturus the tire
mendous velocity OF 3sl miles per
second-a distance 40 miles greater
than that which separates Cincinnati
from ~. Louis. Imagine "A body NOV
ing from this city 20 the Mississippi
river between the ticks of n clock.
Now, DIR. Elkin admits that there is
what Is technically called probable
error" in his observations, but that
error is ~ or -, and would be as liable
10 make the value of the parallax less
than the figure named AZ To make IL
more. ~ that while the velocity of
Arcturus may be fifty or 100 miles less
per second than computed, IL may
possibly be fifty or 100 miles more.
But until we get new data, based on
more extended observations, made with
better instruments, we may, in com
plny with the leading astronomers of
the world, accept DIR. Ellxin's startling
figures, and consider Arcturus as lsi
light years away, and rushing through
space with the unparalleled velocity of
ISL miles per second, or about twenty
one times faster than the earth travels
in It's orbit around the sun.
Is such velocity impossible? is IL
Incredible Is il unreasonable?
II has been automatically demon
strated that the velocity with which
matter, drawn from distant space,
would fall upon the surface of the sun
is no less than $50 miles per second, "A
velocity IL will be seen, almost iden-
teal with that OF Arcturus.
Many cornets which come from inter
stellar regions and visit our solar sys-
tenn sweep around the sun at perihe-
lion with velocities even higher than
that ascribcd 70 hrcturus, and, moving
in parabolic curves, again plunge out
ward into distant space, and passing
beyond the dominion of our own sun,
enter that Of some other mighty star.
Thus far have been considering the
velocity of Arcturus perpendicular To
or across the line of sight. But we
have seen i'm the case of Sirius. that
while IL is moving with the compare
lively low speed OF o miles across the
line OF sight, IL Is receding along the
line OF sight with the high velocity OF
90 miles per second. How Is IL with
Arcturus? Is he approaching or reced-
ing from us? MIR. lluggins again
comes 60 our aid with his spectroscope,
and finds that, while Sirius Is moving
away from us AT the rate Of 90 miles
per second, Arcturus Is rushing down
upon us with the far higher velocity OF
- miles per second,
But we ne "a haven Il ar o a collisi IN.
approach us for tens OF thousands OF
years 10 come. till he arrives within
l4O light years or SO. he will then,
after computablc period gradually
and then rapidly recedc from us and
from our part OF the sidercal universe,
and pursuing AN answering course,
with undated velocity, he will, in "a
few million years pass entirely out OF
the ken OF the most powerful earthly
telescope For, while Arcturus Is now
approaching us at the rate Of So
miles per second, he Is moving athwart
our line OF vision 3sl miles in the same
moment OF time.
But part OF that apparent motion OF
approach ON the part OF Arcturus Is
caused by the movement OF our own
sun, which. with its train OF attendant
worlds. swings along through space at
the estimated rate 81 fifteen miles per
second It's course Is directed toward
the constellation Hercules, between
Acturus and the Milky Way.
And now. having obtained some idea,
however crude, OF the great distance
and rapid motions of this remarkable
ar. we are curious 20 learn something
Of his magnitude and physical struc-
ture IL lac had visible com panion
circling around him, as u the case with
Sirius, Alpha Ccntauri. and some other
airs which exhibit measurable paral-
lax. we could weigh his mass, or rather
the combined mass of the two bodies,
and thence infer his probable magni-
tudc. Hut Arcturus Is solitary star.
No telescope has revealed any attend
ant companion.
Our only resource, then, Ii % com
pare his light giving power with that
OF other luminous bodies, ani accept
such conclusion as may b. fairly
drawn.
Their, are three well defined classes
of stars. judged by the quality Of light
they yield. I'm the first class are the
clear white and blush white stars like
Sirius and Vega. these are supposed %