New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1892-02-15
WHY THE AURORA DESCRIBES STUDY

In an auroral display like that OF SATURDAY
evening that which interests most people IL A'o
general aspect the magniticence of the Diaze' anu
its fuctnating brilliancy and color. But carelul
study OF its details by accurate observers "ouii
prove of great value to SCIENCE. There are many
things which data Of this sort may help us 10
discover
One is the height to which the atmosphere
extends above the earth. This distance was 1or-
merly estimated at from forty-five TO fifty miles,
the refraction of fight at sunrise and sunset by
the air being used as the lfsls OF computations
But it has been found, from simultaneous observa-
tiens of meteors, at points FAR enough apart
to give large angle, that these bodies niaue
incandescent by friction with the Atmosphere
wore at least 100 miles above the earth when first
seen agow Similar calculations from single
features OF an aurora have led to the belief that
the limits are still further away. Dr. 'eeder
thinks the display Of January 5, 1892, had an
altitude Of 10 miles; and as this manifestation Is
atmospheric, we may have to modify our figures
still further.
The close general correspondence, in point OF
time. between the northern lights and dis
turbanccs Of the earth's magnetism, Is already
well established: but there is much yet to be
learned about the mechanism of the relationship
I'm both phenomena there is an almost constant
ouiyer Some unseen and mysterious influence
from illimitable space smites our little globe;
and instantly the atmoSp here about us pulsates
with flame and over large part OF the earth
COMPASS needles 90 into Mysteries What connec-
ton is there between each spasn OF the one
fantastic performance and of the other?
Again. what is the exciting cause itself? Mag
netiSm, we say, from the sun In what manner
does this disturbance proceed? Professor Blge-
lows studies Of terrestrial magnetism lead him
70 believe that there are two sets of magnetic
radiations from the TO the earth, one IN
straight lines parallel to light-rays, the other
originating in the coronal envelope of the central
orb. and following curved lines that implnge
upon the earth almost perpendicuarly to the
cciptic. How much OF one of these magnetic
storms is due to impulses directed along the one
route and how much 10 the other? Professor
Bcelow is. we believe, wrestling with That very
problem lust now, and with good prospects OF
solving il. A. one step toward reaching that
result. he has invented special instrument for
use in measuring the curvature of anroral stream
ers. II is hard to avoid asking again. right
here what is the nature OF that wonderful
medium, the universal ether, through which is
propagatcd these marvellous forces from
heavenly body 10 another?
Then too, how is magnetic impulse generated?
What takes place on the sun, or In the sun Ihe
periods Of greatest auroral frequency are usually
concident with those of greatest sunspot abun-
dance and many single exhibitions, like that of
last Saturday evening, are simultaneous with
the appearance Of such huge spots or spot groups
as the one several times mentioned in The Tribune
within a few days; but sometimes spots are
visibe-big ones, tOo-wlth no attendant terres-
trial disturbance whatever In the case the
suns luminous covering is being violently agi-
tacd, and rapid changes in the shape and size
and position of the spots occur; and in the other
"a more quiet condition prevails in the
Lhotosphcre around the craters. But how
do the terrific EXPLOSIONS, upheavas and
general turbulence in that blazing sea excite and
give out electricity? Widely extended precise
and systematic observations of auroras may all
in finding answers to all of these and some other
questions.