The Caucasian. (Shreveport, La.) 1900-192?, 1910-01-02
DIFFICULT TO KNOW WHEN IT
HAS BEEN REACHED.
CAPT. JOHN S. BARNEj
His Experience as an Arctic Naval OF
fcer-Why Should Cook or Peary Be
Discredited?

servationS, says in the bulletin of tht
American Geographic Society:
All navigators, even in well-known
seas, know the liability to serious er-
ror in establishing their positions upor
the best charts by what is known as
"dead Reckoning" particularly phen fol
days they have been cropping in fogs
driven by gales, tossed by heavy seas
and suffering from effets of abnormal
weather.
Upon approaching dangerous coasts
the careful navigator makes large safe
ty allowances for the uncertainties at
tending such calculations which de-
pend so largely upon individual judg-
ment as to the strength and direction
of the invisible forces, which are con-
stantly at work, and so frequently drag
the ship to its destruction. Drift or
leeway, the force and direction or ca
PRECIOUS currents, uncertain variations
of compass, local deviations, errors in
marking the speed of the ship, possible
oversight of men, all combined, make
dead reckoning only an approximation
of the true position. of the navigator in
any part of the ocean.
These elements or error are enor-
mously exaggerated in the Attic seas,
and, if DR.. Cooks and Commander
Peary'ss declared positions should de-
pend upon dead reckoning alone, they
migth have extreme difficulty in prov
ing to the satisfaction of competent
judges that either of them had reached
their objective. Without the corrob-
orative evidence of astronomical OBJ
servations, their statements of success
would be regarded mainly as guess
written and courses and distances plot
ted on charts in New York, without
either of them doing more than disap-
pearing from public view for the time
covered by their records.
Throwing aside the dead reckoning
except SO far as it adds to the interest
Of their variations, and may be corrob-
orative in some measure of their prog
ress, it would seem that observations
o fthe suns altitude, both for latitude
and longitude, must be the only means
of fixing, even with approximate GER
Eainty, the position of the observer in
circumpolar regions. The natural hor
lion, broken by ice hummocks, obscured
by vapor, radiation and mirage, gives
but an uncertain point of contact with
The suns lower limb, and an artificial
horizon is, tire fore, a necessary part
If the equipment.
Artificial horizons are of two de-
of murcury and one a
mirror The former, when the temp
Derature is. at or below the freezing
point, must be warmed artifcialy, and
he latter leveled by spirit levels, adj
ustment screws, and be placed upon a
firm, solid base. Uulesh the spirit levels
are warmed in the temperatures re-
corded, the spirits would freeze and
eveling by them would become inn
The mirror horizon on an unstable base
would not give as satisfactory or truth
;ul results a sthe warmed murcury,
which finds its own level.
The allowances for refraction, excess
i've at such low attitudes of the sun, in
.reased by the extreme cold and obliqui
y OF the suns rays passing through the
misty atmosphere, and depending upon
and thermometrical condi |
ions, form elements of serious error
n observations, depending largely upon
he individual judgment of the observer.
The chronometers, or chronometer |
regulated to Greenwich or
Washington time in temperate eli
nate, can not be expected to go on from
month to month and year to year with !
-bsolute precision, particularly in such
whether carried on the
,erson or transported on sleds and sub |
ected to violent shocks Longitudes OBJ
aimed by them may easily be erroneous
where one degree of longitude is
rarely one nautical mile It is extremely
doubtful if any navigator, however
killful, can find with approximate pre-
ision his longitude at or near the pole,
Inless by a series of observations ex-
ending over number of days, using /
he most accurate instruments and
correct thermometer.
The best made sextant, handled by
lalf frozen fur clad man can not be in-I
allible It IS doubtful if two observers
t the same time and place, with sepa-
ate but similar sextants, would record /
he same altitude. Like all delicately
sdjusted instruments, extreme careful (
1855 is necessary to preserve its integ
ity
The results of Azin1uth observations, T
f carefully and systematically made
With proper instruments, would consti-
ute valuable contributions to scientific /
as to variations Of the COM