The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1880-11-20
NEWS FROM THE NORTH.
Lieutenant Schwafka on the forma'
ton OF Icebergs aud Lcnsth
of Arctic winters.

| ton OF IceDeESs dHu hSnSs"
of Arctic winters.
Al the opening of the Wednesday'after-
moon session of the National Academy OF
Science, in New York, Professor Marsh In.
PRODUCED Lieutenant Schwatka. United
STATES navy, who was received with nearly
apDlause, and whose observations on ice
and icebergs in the Polar regions were lis.
| tened TO with interest. The formation OF
| jcebergs from the terminal fronts OF gla-
ciers, lieutenant Schwa ka said, has long
been a disputed point among savants, some
contending that they derive their origin
from the corroding action OF the water IN
dermining their projecting faces until the
weight of the superintendent mass acting on
n lever overcome TIE cohesive power OF The
glacier a,ong some line OF least resistance,
when the berg fell into the sea and was
waited away by the tide, winds, and cur
rents. Others could only account for such
| huge mountains OF ice by supposing tnat
| the glacier, slowly crawling Into the sea ana
plunglDg beneath denser nuld, had
| buoyaut effort or tendency TO rise, when al
| last became so great that 1t oyercame tne
| line of least resistance near the shore, ana
| the berg rose into the sea to be at the tur-
iber mercy of its uncertain elements. Both
|
former generally occurs where currents
heated in more temperate climes pour their
TEND waters norlhward and eXpend their
thermal forces in contending with the
vast packs, flows, and glaciers OF ice that OBJ
strllct their polar march, and whose last
corroding action has the slow glacier only a
comparatiyely short time in its embraces De-
fore IL has undermined 1t. The latter re-
sul,s where the chilled waters from the
Pole have but little effect upon The glacial
fraDt: and slow as it is, 1t has time 10 crawl
into the sea to give forth its mighty masses.
Sometimes both kinds OF forces are aching
simultaneously upon the same glacier, and
while huge icy mountains are at intervals oi
centuries rising from their dense. watery
he'd. other aud smaller ones are more ire
ouept,y dropping from its seward face, i0r
those formed by dropping are lar smaller
than those which rise into the sea. Although
about scyen.eighths Of an iceberg Is SUBJ
merged. il must not be inferred that when lis
height has been determined, seven times thai
height is its depth below the sea-level. ii
of a tabular shape, this proportion becomes
more nearly correct; but IL OF pyrimidal
or couordal cross section, which Is lar Oh
tener the case, the lineal proportions OF
height TO depth approach each other more
closely, while the volumes necessary to
hydroststic equilibrium remain lnvariaDie
Tbeir great height, as compared with thelf
breadth, would SLOW that these llneal pro
por,ious did not obtain beneath the sea
level. or the mass, il homogeneous, could
| not lie In a state OF stable equilibrium, snC
J would iopple oyer-a fact which sometime:
haepcns when the conditions OF equilibrium
, are disturbed by the unsymmetrical de
crease Of It's different faces.
The height Of bergs, estimated or mea
sured by various Arctic yoyagers, varies
, grestly. During the warm months OF sum
mer, when tbey are most frequently en-
couptercd by navigatOrs, they are oIter
surrounded by hazy mist, due TO the con-
ldensation Of the surrounding moisture by
!, their chilly faces, aud the effect Is TO make
them appear as much big her than they really
are. which renders estimates OF their height
particularly unreliable.
AS about seven-eighths OF an iceberg Il
under water, the curious spectacle Whicf
has often been seen in Polar ATTITUDES OIL
Ithese monsters ploughing their way against
a rspid current loaded with heavy pack-ict
? and liz the very teeth OF strong gale OF
wind can be readily understood on tht
theory that the surface current is shallow
? aud the drifting colossus is only obeying th'
mandates Of 4 deeper and more powerful
agent
DURATION OF ARCTIC WINTER.
Lieutenant Schwatka also read short pa
per on the duration OF the Arctic winter
The gcnerally-receiyed opinion, said he, tina
, the Arctic winter, especially in the higbel
| attitudes, Is a long dreary one OF perfec
OPAQUE darkness, is not strictly correct
, Ia latitude $50 2V 30" NJ, the bighes
point ever reached by man, there are fou
! lhouss and forty.two minutes OF twi
, light on December 22d, the shortest day il
the year, in the Northern Hemisphere
! In latitude so 27> N, the highest poin
where white men have wintered, there ART
/. six hours and two minutes in the shortt S
, day, aud latitude $40 32> n, 172 geographi
} cal mites nearer the North Pole than Marx
ham reach, aud S2s geographical miles iron
: that point, must yet be attained beiore I'M
, ltrue Piutonic zone, or that one In whicl
{ there Is no twilight whatsoever, even upor
the shortes. day OF the year, can be said u
. have been entered by man. OF course a6ou
|, the beginning and ending OF this twilight
/ | II is very feeble and easily extinguished by
even the slightest mists, but nevertheless
: exists, and is quite appreciaose on clea
E Geld days, or nights, properly speaking
8 Tue NORTH Pole itse,i Is only shrouded II
! perfect blackness from November 1911
] TO January 20 b, period OF seventy-seyei
Z dajs. Surprising that the sun has set lsup
!. posing q crodm-polar sea or body OF wate
y | unlimited TO yisiop) on September 9th, no
e 10 rise until March 18th, for that particular
y point, giving period Of about fifty day
0 OF uniformly varying twilight, the pole ha'
8 about one hundred and lightweight days o
8 continuous daylight, one hundred days o
varying twilight, and seventy-seyen OF per
feet iDky darkness (saye when the moor
has q northern declination) In the period o
0 typical year. During the period OF lit
il tie oyes four. days tue sun shines continll
J. obsly on both the North and South Pole
Q at The same time, owing TO refraction paral
|. ID lay sesnE-diamefer aud din Of the h0rizon