The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1850-08-23

! TO be the following, comprehsnding both such a
are generally admitted to be the leading facts, o.
! laws, and such are deemed somewhat new, OF
| at least not universally received as established
truths.
1. That an Aurora of the first class usually com.
mences near the end of the evening twilight, in
the form of northern light, rerembling the dawn;
that il usually arrives at its maximum al all places.
however differing in longitude, at the same part OF
the night, namely from 10 TO ii O'Clock, and more
| frequently little before ii and that Auroras Of
the highest order frequently continue all night,
while those of ordinary character commonly
| end before midnight
2. That a great aurora is usually pre- ceded by a
large bank, or cloud, OF peculiar vapor, differing
In lis nature from ordinary clouds, commonly exhi-
| biting milky appearance, but sometimes a smoky
hue, or the two mixed together and that the ex-
tent and density of this aurora vapor resting upon
the northern horizon, forms the best prognCstc we
| have OF the probable intensity of the exhibition
which is to follow, composing, we believe, the
material of which the successive forms of the au-
| FORA are constituted
8. That the auroral waves, when peculiarly grand
make their appearance later than the streamers and
arches, and usually later than the corona, con-
unued TO later hour of the night, appear at lower
level than the streamers, and roll upward, in the
direction of the streamers toward the point of
general concourse.
T. That auroral exhibitions of the higher order
are commonly OF great extent, spreading over no
nconsiderable part of the earth's surface, and
reaching to great but variable, height.
8. That auroras of the first class have three dis
tinct forms of periodicty-a diurnal periodicity,
mencing, arriving at the maximum, and end
ing at definite hours of the night, as already
serted; an annual periodically, rarely never
occurring in June, and the greatest number of the
highest order clustering about November, these
last bearing striking resemblance to each other;
and secular periodicity the most remarkable of
all, recurring in great series which we have demo-
minated 4" Auroral Visitations." That the vista
tons most marked and best defined, occur at in
tevals Of about 65 years, reconng from the middle
of one period, to the middle of the next period,
and last from 20 to ~ years, making the interval
from the end of one to the beginning of the next,
about As years.
6. Thai, while the forms of the aurora usually
appear TO be under the control of magnetic forces
yet this is not always the case since the arches do
not always eliminate in the magnetic meridian,
nor do they always place themselves at right
angles TO the meridian, nor does the effect on
the needle correspond to the different states of
intensity of the aurora.
Z. That the aurora has remarkable geographical
relations, belonging chiefly to the higher attitudes,
and only in the great visitatons descending below
the latitude of 40 degrees but descending lower on
the western than the eastern continent and pre-
vailing more in the northern than in the southern
hemispheres.
The foregoing seven propositions appear to en-
brace the most important facts respecting auroral
exhibitions, and are, therefore, deemed TO be, in
the present state Of knowledge, the laws of the
aurora borealis. But We cannot rest satisfied to
let this great visitation of the phenomenon-whch,
in its whole progress and duration, we have enjoyed
fair opportunities tor obs 'rving-pass by, without
effort to assign its true origin, and to explain
the causes of its myterious phenomena.
After the phenomena of thunder and lightning
were first proved, by Franklin, to be caused by
electricity, it was taken for granted, almost with
out discussion, that the aurora boreas is produced
by the same agent; and this hypothesis has still
very numerous adherents. We endeavor then,
first, to show that the aurora berealis is not pro-
duced by electricity IL That it is unsafe to pre-
dictate an identity OF origin, from resemblance
he md pFfQ nf 81
tricity in passing through exhausted tube, and
that the resemblance itself is greatly overrated 2
That such an origin is inconsistent with the great
extent of the phenomenon. 3. That the electro
meters do not indicate the presence Of electricity in
any unusual degree, during an aurora. 4. That
these exhibitions are scarcely known in The equa-
torial regions, where electricity is most abundant,
and prevail most in the polar regions, where thun-
der and lightning are unknown. 8. That this
cause il incompetent to account for the aurora va
por, the material Of the aurora itself o. That the
motions OF the aurora vapor, in its c0rruscatiOns
too rapid to be caused by electrical attractions
and repulsions, but not sufficiently rapid for the
electric fluid itself Finally That electricity 10
inadequate to account for the pendcity of the auro
"a, II not entirely inconsistent with the secular
periodicity.
But magnetism has more claims than elasticity
TO be considered as the true Cause Of the aurora
borealis since il is acknowledged that the forms
and positions which the streameTs, the arches and
the corona, assume, are intimately related TO
magnetism, and that the magnetic needle itself
| confirms ana establishes This relation. but TINS
proves merely that the matter Of the aurora has
magnetic properties, but decides nothing with
spect to the origin Of the aurora, which is the pn
cipal thing TO be accounted for; while magnetism,
like electricity, is inadequate TO account for the
extent for the light, for the notions for the mate
rial and especially for the perodicity Of the aurora
Dissatisfied with the attempts which have been
made to acco9n, for the origin, or 70 eIplaio the
or magnetism, or from any other cause OF terrs-
uisl nature, we next look for the source TO the
pansiary spaces, and arrive at the CONCLUSION that
The phenomena Of the aurora belong, indeed,
TO the atmosphere, since they are affected by the
esrth's durnal rotation; but the source OF the
matter OF which the meteor rs composed. we hold
to be derived from regions above the atmosphere.
This distinction we deem OF much importance
in investigating true theory of the aurora, name
Y, that the exhibitions are atmospheric, while
the source or origin is cosmical We, therefore,
inquire first at what height in the atmosphere the
annual exhibitions take placet
We conclude that while some OF the forms OF the
meteor, ms the corona, unsuitable for this nves
CATION, being merely the effect Of perspective, yet
that there are other forns, which may be- used for
parallax no less than common cloud, the upper
line of well defined arch, some single rag
msnt Of an suroral cloud, unconnecfed with other
parts Of the exhibition, and Of a form 70 peculiar
as To arrest the attention OF observers al some dis
lance from each other. From extensive com
Tarison OF data, we arrive at the conclusion that
the height OF the aurora IN very variable, some
times reaching elevation Of at least 100 miles, and
at other times rising but tle above the region Of
the clouds; stu we attempt To prove that the tes
timony Of Farqusrson, that auroras are sometimes
seen below the clouds, is not conclusive; nor thai
Of Parry, Richardson, and others, who have as
serted that, In the Polar seas, auroras sometimes
appear between the spectator and the icebergs, at
little distance.
II is required Of theory that IL be a legitimate
deduction Of well established truths, and Il IL re-
9uirtd Of hypothesis that IL explain the leading
facts, and that II be not inconsistent with any
known facts. An explanation which uniies the
characters OF bolh-whIch ~, at once, an infc-
renee nom acknowledged truths, and which affords
an adequate solution Of the leading phenomena,
while IL is not inconsistent with any known facts
although IL may not be ready account for them,
such an explanation Is deemed peculiarly worthy
OF confidence until a tctier cen he proposed. Ia |
conformity with thsse principles we endcayor hrst |
10 infer the cosmcisl origin Of the borcalis
frcm known facts; secondly, we investigate, as Tar