I Meteorologien reducere vi Barometerhøjderne til Hav- 
fladen. Vi skulde reducere dem til en bestemt Niveauflade. 
Som Pl. XLVIII viser, ligger Havets Niveau ved Christiania 
omtrent 1.5 Meter højt, medens det ved Vardø kun ligger 0.9 
Meter højt. Forskjellen er 0.6 Meter, hvortil svarer en For- 
skjel i Barometerhøjden af 0.05 mm. Da denne Størrelse 
er Grændsen for den Nojagtighed, hvormed vore Stations- 
barometres constante Correction er bestemt, har Havets 
Niveauforskjel mgen praktisk Betydning for Lufttrykkets 
Reduction til Niveauflade. 
Ude i Midten af Havet ligger Overfladen 1.5 m lavere 
end Niveauet ved Christiana. Her bliver Reductionen til 
det sidste over 0.1 mm. Dette er imidlertid en Størrelse, 
som ikke overstiger den Usikkerhed, man i Almindelighed 
kan paaregne ved Barometerobservationer paa Havet". For 
vort Lufttrykkart, Pl. XXXI, er den, med dettes Usikker- 
hed, af ringe Betydning. 
14. Slutningsbemerkninger. 
I den foreliggende Afhandling har jeg søgt at be- 
erunde Vandets Bevægelse 1 vort Nordhav som en Følge 
saavel af de normale Vinde som af Ulighederne 1 Vandets 
Tæthed. Den første Aarsag er den overvejende, men den 
sidste har ogsaa sin fulde Betydning. Jeg betragter dette Ar- 
bejde som et Forsøg, dog ikke som en blot og bar Hypothese, 
men som en ved consekvente Beregninger gjennemført Ide- 
række, der, udgaaende fra kjendte Kræfter og deres Virke- 
maade, har ledet til Resultater, som i mange Henseender og 1 
mange Punkter stemme overens med de af Observationerne 
givne virkelige Forhold. De Coefficienter, jeg har benyttet, 
f. Ex. Forholdet mellem Vindhastighed og Strømhastighed, 
Grændsefladens Dybde, trænge til yderligere Veritication, og 
de numeriske Data have for vigtige Punkters Vedkommende 
været magre, navnlig gjælder dette Sovandets specifiske Vægt, 
Lufttrykkets Fordeling over Havet og tildels Dybderne. 
Jeg maa bede erindret, at da vi 1 1876 rejste ud paa vor 
Expedition, havde jeg ikke nogen bestemt Tanke om, at 
det skulde blive muligt at række saa langt med mine Stu- 
Alt 
kjendt, og Dybder, Temperatur og Vandets chemiske Egen- 
skaber indtoge den første Plads i vore Tanker. At det 
har været mig muligt at føre Arbejdet saa vidt, som skeet 
er, skyldes for en væsentlig Del mine Medarbejdere, Com- 
mandørcaptein Wille, der havde organiseret Lodningerne, 
og hans Officierer, der assisterede ham i deres Udførelse, 
Captein Petersen og Captein Grieg, Professor Waage, der 
organiserede de chemiske Arbejder, og Chemikerne Svend- 
/ 
dier som til den oceaniske Circulation. var da ube- 
1 Den norske Nordhavs-Expedition. Meteorologi. Af H. Mohn. 
Side 40. 
195 
resulting from the great rivers, the Oder and the Vistula, 
the water of which is carried east, towards Memel. 
In meteorology, it is the custom to reduce the heights 
of the barometer to the sea-level. We should rather 
reduce them to a given surface of level. As shown by 
Pl. XL VIII, the level of the sea at Christiania lies about 
1.5 metre high, whereas at Vardo it lies only 0.9 metre 
high. The difference is 0.6 metre, to which corresponds 
a difference in the height of the barometer of 0.05 mm. 
As this quantity represents the limit fof accuracy with 
which the constant correction of our Station-Barometers is 
determined, the difference in the sea-level has no practical 
importance for the reduction of atmospheric pressure to 
a surface of level. 
In the middle of the Sea, the surface lies 1.5 m. lower 
than the level at Christiania. There, the reduction to the 
latter will be more than 0.1 mm. Meanwhile this 
quantity that does not exceed the uncertainty we as a rule 
expect with barometric observations at sea.’ As 
regards our Map of Atmospheric Pressure, Pl. XX XI, with 
its inherent uncertainty, it is of trifling importance. 
IS 8) 
may 
14. Concluding Remarks. 
In the present Memoir, I have sought to explain the 
motion of the water in the North Ocean as produced alike 
by the normal winds and the differences in the density 
of the water. The former cause predominates, but the 
latter too has full significance. I regard this research 
as an attempt, not indeed as a mere hypothesis but as a 
consistent computations, 
which, proceeding from known forces and their mode of 
action, have led to results that in many respects and on 
series of ideas carried out by 
many heads agree with the actual results given by the 
observations. The coefficients made use of, e.g., the rela- 
tion between the wind-velocity and the current-velocity, 
the depth of the limiting-surface, need additional verifica- 
tion, and in many important points the numerical data 
have proved but meagre: this applies in particular to the 
specific gravity of the sea-water, the distribution of atmospheric 
pressure over the sea, and partly to the depths. The reader 
must bear in mind that, when, in 1876, we started on our 
Expedition, I had no definite idea of being able to advance 
so far with my studies as oceanic circulation. All was 
then an unknown field of research, and depth, temperature, 
and the chemical properties of water laid claim to the 
first place in our labours. The possibility of my having 
carried on the investigations to so advanced a stage, must be 
ascribed in great measure to my colaborators: Commodore 
Wille, who organised the soundings, and his officers, who 
assisted him in taking them, Capt. Petersen and Capt. 
Grieg; Professor Waage, who organised the chemical work, 
1 The Norwegian North-Atlantic Expedition. 
Meteorology. 
By H. Mohn. P. 40. 
bo 
or 
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