The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1885-10-31

the air from the multitude of points, which
light, analysed by the spectrum, was in
IDENTICAL with that of the northern lights.
From this fact, indeed, Lemstrom very
naturally concluded that the aurora bore
ais was terrestrial display, or very near
the surface of the earth; but in these
claims he has been stoutly contested by
others, many of whom claim tkdee the dis
tance to the auroral arcs has been measured
to considerable degree of accuracy, and
they all agree that it is quite high, supra
atmospheric, supposing the air to be forty
six miles deep.
1t is too much within the domain of drY
mathematics to discuss at length the diff.
ferent methods employed by different OBJ
servers to determine that height, but the
results attained would be interesting, no
doubt. Lemstrom, as / have said, thought
it might reach to the ground, and has pro-
ducedit in an artificial way therefrom. Sir
John Ross, believe it was, who said that
heand some companions distinctly saw bril-
liant ray of the aurora pass between him
and a high snow-covered hill not many
miles distant Sir John Franklin's meas
urements in North America show it to be
seven miles high. The French at Bosse-
kop, Norway, as early as 1889, got it
up to between 60 and 120 miles. from
holt put it at about seventy, and he has
made more measurements and studied this
part of the subject closer than most ply
sicists. Nordenskjold, the arctic explorer,
puts it at 118 miles, which Professor Fearn-
ley follows closely at 125, and Newton gets
but five miles more, or 130, as result of
his deductions. Somewhere in the vicinity
of the numbers given above will probably
be found the true values, if they are ever
determined, and it may be that all are
within the true limits, for, like the clouds,
as one of the above authors remarks, the
auroral displays may be found to have wide
limits in their heights. Bergman does not
rest contented, however, until he has pub
lished the height at 469 miles, Marian 485,
and Boscovich at 825. l have not given
all authorities, but probably the most re-
liable and the greatest extremes.
The extent of auroral displays over the
world is not uniform, the United States
being the most favored, while Siberia, OPP
posite to us across the pole, but much fur
ther north, is the least. New York city
has about the same frequency of auroral
displays at st. Petersburg and London, and
also as Siberia, more than half way up the
Behring seacoast, fully 1900 to 1000
miles nearer the pole They are seen as
far south as Cuba, Yucatan, Central Mexico,
and Cape St. Lucas on the American con-
tinent, while in Asia they are unknown in
Pekin, and almost so in the Japanese Is
lands, Southern Europe, on the latitude of
New York city, being just within the limits
of visibility. In general, it is seen about
l 400 miles further south on the Western
continent side that it is on the Eastern, or
Just the distance the magnetic pole is from
the true or geographical one, pulled over
the same side, so to speak, it being just
north of our continent. 1t thus plainly
shows that the magnetic pole is central
point from which the auroral force in some
unknown way is dependent. The magnetic
pole, approximately speaking, is on longi-
tude 100 degrees west from Greenwich,
and on that meridian the displays are more
frequent than other points of the same lati-
tude. A display in New York city would
be seen to better advantage, weather per-
mitting, at about North Platte, Nebraska,
on nearly the same latitude. A person
travelling north from New York city
would see the auroral displays increase
until Hudson strait was almost reached,
when they would show their maximum
number, being practically constant or visi-
BILE every night. AS the journey continu-
ed they would decrease, and by the time the
pole was reached it is not unfair to infer
that the displays may have degenerated
into the New York standard of frequency
again.
The auroral displays are not the most
frequent at the magnetic pole, as come
might infer at first sight from all that has
been said, but about 500 miles south from
that point, not very far from my winter
camp in north Hudson's bay. l spent a
small portion of winter nearer the mag
netic pole than any other white person has,
and the paucity of auroral displays was
marked although considerable trouble was
taken to watch for them should they occur.
They were also particularly weak in effect
Further south, on the shores of northern
Hudsons bay, noticed them much more
frequently, and Chesterfield inlet, which
puts off from the northwest corner of the
bay, is called Ak-shar-nak by the Esqui-
maux, which means the aurora borealis in
their language, on the whole signifying
''the place of the northern lights" From
our camp in Hudson's bay the highest
point of the auroral arc seemed to bear
about west-southwest from us whenever the
display seemed to take that form; but long
rolling ribbons, like the streamers of ban
ner in gentle breeze, seemed to be the
most common, lashing the sky lazily back
ward and forward like a huge serpent, while
every now and then some part of the broad
ribbon would be suddenly Illuminated, and
from this part would spring rigid bars of
fame toward the zenith, and this bright
part would seem to run along the restless
ribbon like pulsating wave of light. The
displays were seldom strong enough to give
any other color but white, but now and
then we had show of light red or green.
never saw an auroral display in the arctic
or subarctic countries countries equal in
grand effect, wide extent and brilliancy OF
colors to that which l saw at West Point,
N. Y, in the spring of 1871, as near as |
can recall the date.
The aurora borealis has daily huctua-
ton of frequency and brilliancy, seeming
to be more marked at certain hours, and
these times growing later in the night as
the magnetic pole is reached. In from
holt's tables we find this time at Quebec,
Canada, about 1920 p. M, and computing
by the usual ratio outward for New York
CITY. we would have about 10 o'clock in the
night as the result. There are also yearly
fluctuations, showing to the best advantage
about the latter part of September and
March, and to the poorest about the latter
part of June and December, or near the
eouinoxes and solstices. The most inter-
esting variation is the one called the eleven
yearly period, occurring at the same time
and same period of maximum and mini
mum frequency with the spots on the sun,
and between which some relation must
exist, according to Fritz. Tromholt says
this is true regarding the temperate zone
of the nortL, but in the arctic regions "the
law of relation between the frequency OF
sun-spots and aurora is reserved.
On the southern half of the world we