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jeg til Observationsuhr et Lomniechronometer, der var
provet paa Observatoriet i Neufchatel.
Boxchronometrene havde sin Plads ombord i et Skab
i Arbeidssalonen. De bleve hver Morgen optrukne og
sammenlignede indbyrdes. I 1876 tjente Kuliberg som
Hoveduhr og i 1877 og 1878 Reid. Kun Hoveduhret har
været benyttet til Længdebestemmelserne, da. det viste sig
at have en meget jevnere Gang end de øvrige. Under
Rejserne blev det af de daglige Sammenligninger
consta-teret. at der ikke indtraf nogen merkelig Forrykkelse i
Høveduhrets daglige Gang.
Ved Observationer paa Land eller paa Dæk
benyttedes saagodtsom uden Undtagelse et af de andre
Boxchrono-metre eller et Lomniechronometer, stundom ogsaa et
almindeligt Lommeuhr. I ethvert Tilfælde blev
Observations-uhret sammenlignet med Hoveduhret før’ og efter
Observationerne.
For Expeditionen tiltraadte sine Rejser, bleve
Boxchronometrene. med Undtagelse af Reid. daglig
sammenlignede med Pendeluhret paa Observatoriet i Bergen af
dettes Bestyrer. Hr. A strand. Under Expeditionens
Ophold i norske Havne blev deres Stand for Greenwich
Middeltid bestemt ved de fra Observatoriet i Christiania
gjennem Telegrafen givne Tidssignaler. Disse gives hver
Søndag og hver Onsdag Morgen. Signalapparatet (Morse’s)
staar lige ved Siden af Observatoriets Normalpendel. Der
gives liver Gang 3 Signaler, nemlig 8’4 59™ O’, 9’1 O’" 0" og
()/, \m øs Greenwich Middeltid om Søndagene .og 7’’ 59’" 0Ä,
8A 0m 0S og 8A lm O om Onsdagene. Tidssignalet, der
høres meget skarpt paa Modtagelsesstationens
Morse-Appa-rat. bestaar i et enkelt Slag. For at skille mellem de 3
Signaler slaaes efter det første 1 Dobbeltslag, efter det
andet 2 og efter det 3die Signal 3 Dobbeltslag.
Signalerne sendes til alle norske Telegrafstationer.
Med Hensyn til Nøjagtigheden af de i det Følgende
givne Tids-, Længde og Bredde-Bestemmelser maa jeg
bemerke Følgende:
Den af Beregningerne udledede sandsynlige Fejl af
en enkelt observeret Højde (paa Land med Stativ og
Kvik-søl vhorizont) er omkring + 5". Der er imidlertid, som
det paa sit Sted skal vises, Tegn til. at der. foruden de
egentlige tilfældige Observationsfejl. optræder constante Fejl,
hvis Aarsag kunne ligge i forskjellige Omstændigheder, som
i Bestemmelsen af Indexfejlen. mangelfuld Justering af
Instrumentet. Excentricitet m. m. Hvad Indexfejlen angaar,
da er den i Regelen bestemt samtidig med Observationerne
og ved gjennemsnitlig 4 Satser Dobbetøcontacter af
Solrenderne. Middelfejlen af Resultatet af en enkelt Sats
finder jeg at være + 5".7 og Middelfejlen for en
Bestemmelse af Indexfejlen skulde saaledes være + 2".85.
Instrumentet holdtes altid godt justeret og om Excentricitet
af nogen merkelig Virkning nævner Prof. Hansteen ikke
Noget. Ved Observationerne i Hammerfest (Fuglenes) og
i Bodø antydes imidlertid Tilstedeværelsen af constante Feil
i Højden af respektive -j-8" og—8". En Del heraf kunde
box-chronometer by Reid. and in the latter year I took
observations with a pocket-chronometer, tested at the
Observatory of Neufchatel.
The box-chronometers were kept in a cupboard in the
work-room. They were wound up every morning and duly
compared. In 1876, Kullbergs served as chief time-keeper,
in 1867 and 1878 that by Reid. For determinations of
longitude, exclusive use was made of the chief time-keeper,
its rate having proved much more uniform than that
of the other chronometers. On each cruise the result of
the daily comparison showed that no appreciable disturbance
had occurred in the diurnal ,rate of the chief tiuie-keeper.
For observations on shore, or from the deck of the
vessel, we used almost without exception one of the other
box-chronometers, or a pocket-chronometer, nay sometimes
a watch. The chronometer or watch, whichever it might
be. was. however, invariably compared with the chief
timekeeper both before and after the observations.
Previous to the departure of the Expedition on its
several cruises, the brtx-chronometers. with the exception
of Reid’s, were daily compared with the standard-çlock of
the Bergen Observatory, by the Director, Mr. Astrand.
During the stay of the Expedition at Norwegian ports,
their error on Greenwich mean time was determined by
the time-signals telegraphed from the ()bservatory at
Christiania. These signals are sent every Sunday an.d
Wednesday morning. The signalling apparatus (Morse s) stands
close beside the standard-clock of the Observatory. Three
signals are given, viz. at 8;’ 59’" 0s. 9’’ O’" 0s, and 9" lm-0s,
Greenwich mean time, on Sundays, and at l’’ 59m 0s, 8A
O’" 0s and 8A l’" 0s on Wednesdays. Each signal, distinctly,
delivered by the apparatus of the receiving-station, consists
of a single click. As a means of readily distinguishing
between the 3 signals, the first is followed by a double-click,
the second by 2 double-clicks, and the third by 3. These
signals are transmitted to all Norwegian telegraph-stations.
As regards the accuracy of the observations for
determining time, latitude, and longitude, I must observe
as ’follows: —
The computed probable error of a single observed
altitude (using on shore the sextant with a stand and
mercury-horizon) is about + 5". . Meanwhile, there is reason
to believe, as will afterwards appear, that, apart from the
accidental errors of observation, certain constant errors
occur, arising probably from various sources, such as the
determination of the index-error, imperfect adjustment of the
instrument, excentricitv, &c. With regard to the
index-error. this has usually been determined when taking the
observations, and on an average from 4 sets of double
contacts ol’ the solar limbs. The mean error of the result of
one double contact I found to be + 5".7. and the mean
error of the determination of the index-error should
accordingly have been + 2".85. The instrument was always
kept well adjusted, and of excentricitv that could have any
appreciable effect. Hansteen says nothing whatever.
Meanwhile. the observations taken at Hammerfest (Fuglenes) and
at Bodö indicate the existence of constant errors, in the
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