nedover mod Dybet. Dette vises blandt andet af følgende 
Observationsrækker fra Svolvær 1 Lofoten, tagne 1 den sidste 
Uge af Januar 1878 ved Opsynschefen, Capt. Juel's For- 
anstaltning. Stationerne I til IV følge efter hverandre fra 
Land af udover Søen. — 
Station I JØTill 
Bundens Dybde i Favne 
Temperatur i o Favnes Dyb 10.4 OD) 
å 5 ie oS 
Isothermobatherne ligge, i et Verticalsnit, paa skraa, 
og Normalen paa dem, trukket fra hojere til lavere Tem- 
peraturer, peger opad og mod Land. Da Luftens Tempe- 
ratur paa denne Aarstid er lavere end Havoverfladens og 
lavere over Land end over Havet, henvises vi til Kulden 
over Landet som Aarsag til Temperaturens ejendommelige 
Fordeling i Havet under Kysten om Vinteren. 
At denne Afkjøling fra oven væsentlig foregaar ved 
Ledning og ikke ved nedgaaende Strømninger af afkjølet 
Vand, sees af følgende Exempel. Expeditionens Chemiker, 
Hr. Svendsen, observerede i Juni 1876 ved Husø?, Mun- 
707 
. g Vo 
dingen af Sognefjorden, en specifisk Vægt ved Tae > Over- 
X 3) 
fladen lig 1.02465, 1 11 Favnes Dyb lig 1.0%492.  Scettes 
Overfladens Temperatur 1 Marts til 49,5, og antages den, 
efter Observationerne fra Svolvær, at voxe med 09.3 til 10 
Favnes Dyb, faar man for Marts, den koldeste Maaned, i 
Overfladen en specifisk Vægt af 1.02567, i 11 Favnes Dyb 
af 1.02590. Den større Saltholdighed i Dybet bevirker 
altsaa, at Overfladens ferskere Vand, selv med dets lavere 
Vintertemperatur, ikke faar nogen Tendents til at synke. 
Smil, S. 89. 
Efter de foreliggende Iagttagelser er den aarlige Va- 
riation af Havets Temperatur størst i Overfladen, aftager 
stadigt med Dybden og forsvinder i 100 Faynes Dyb eller 
lidt dybere. 
6. Temperaturens aarlige Variation i Havets Overflade. 
For at studere Temperaturens Variation 1 Havets 
Overflade har jeg udarbejdet nye Karter over samme for 
Maanederne August og Marts. Jeg har valgt disse Maa- 
1 Tornge, Chemi, IT, S. 59. No. 14—10. 
Den norske Nordhavsexpedition. H. Mohn: 
97 
ward. This appears, ter alia, from the following series 
of observations, taken at Svolver in Lofoten during the 
last week of January 1878, by order ot Capt. Juel, Govnt. 
Inspector of the Lofoten cod-fishery. Stations I o IV 
follow in succession from the land, seaward. 
UI IV Station 
25 70 Depth of Bottom in Fathoms 
PG OG Temperature at Depth of o Fathoms 
5 
2.9 3.0 IO 
3.8 3 5 25 
2 8 35 
5-4 40 
6.1 45 
6.4 50 
6.7 60 
© o77 70 
The isothermobaths lie, in a vertical section, obliquely, 
and their normal, drawn from higher to lower temperatures, 
points upward, and towards land. The temperature of the 
air at that season of the year being lower than the temper- 
ature of the sea-surface, and lower over the land than over 
the sea, we must obviously seek in the cold over the land 
for the cause of so remarkable a distribution of the sea’s 
temperature on the coast during winter. 
That such cooling from above is principally brought 
about by conduction, and not by descending currents of cooled 
water, may be seen from the following observation. Mr. Syend- 
sen, chemist to the Expedition, found in June 1876, at Husø, ? 
off the mouth of the Sognefjord, a specific gravity, reduced 
72 
to equal at the surface of the sea to 1.02465, at a 
Ly 
depth of 11 fathoms to 1.02492. 
temperature in March at 49,5, 
Now, putting the surface- 
and assuming it, from the 
observations taken at Svolvær, to increase 0°.3 down to a 
depth of 10 fathoms, we shall get for March, the coldest 
month, at the surface a specific gravity of 1.02567, at a 
depth of 11 fathoms of 1.02590. The greater proportion 
of salt in the deep is attended therefore with the effect, 
that the comparatively fresh water of the surface, even 
with its lower winter-temperature, has no tendency to sink 
(See p. 89). 
From the observations given above, it follows that 
the annual range of the sea’s temperature is greatest at 
the surface, diminishing steadily with the depth, and ceasing 
altogether at a depth of 100 fathoms, or a trifle deeper. 
8. Annual Variation of Temperature at the Surface 
of the Sea. 
With a view to study the variation of temperature 
at the surface of the sea, I have constructed new maps for 
the months of August and March. These months I selected, 
1 Tornge, Chemistry, III, p. 59. No. 14—19. 
Nordhavets Dybder, Temperatur og Strømninger. 13 
