Mayen turde ogsaa hidrøre, foruden fra den længere gjennem- 
løbne Vej fra Atlanterhavet af, tildels fra, at Foramini- 
ferskallerne her synke i en opstigende Strøm og saaledes 
i længere Tid ere udsatte for Søvandets tærende Virkning. 
Efter Alt synes der saaledes at være god Overensstemmelsé 
de Aflejringer paa Bunden vort 
Strømsystem. 
mellem organiske og 
, 
Efter Zöppritz) fremgaar det nu existerende Strom- 
system som Resultatet af Vindenes Arbejde i seeulære Tids- 
rum. Som jeg har søgt at vise, udføres dette Arbejde 
derigjennem, at der dannes en Overflade, som afviger fra 
Niveaufladen, dels ved Vindenes directe Virkning og Jor- 
dens Rotation, dels ved de af Vindstrømningerne og Elve- 
vandet vedligeholdte Uligheder i Søvandets Tæthed. Hvad 
de normale Vinde, Fordunstning og Nedbør udrette, efterat 
Strømsystemet er blevet constant, er at vedligeholde Strøm- 
fladen og med den Strømsystemet. De normale Vinde ere 
Resultatet af det normale Lufttryks Fordeling, hvilken igjen 
beror paa Temperaturens Fordeling. Men denne er af- 
hængig 1 høj Grad af Havets Temperatur og af Fordelin- 
gen af Land Vand. Vi komme saaledes til Solens 
Varme, Fordelingen af fast Land og Hav og Jordens Ro- 
tation som Hovedfactorer for Klima, Lufttryk, Temperatur, 
Fordunstning, Nedbør, Vinde og Havstrømme. 
og 
Forandringer i disses Grundbetingelser ville medføre 
Forandringer i Havets Strømninger, der kunne blive af stor 
Betydning for Klimatet. Seculære Forandringer af den 
relative Havstand ved Kysterne synes ikke at kunne for- 
klares paa saadan Maade, da Strømfladens største Højde 
over Niveaufladen gjennem Havoverfladens fdybeste [Punkt 
kun gaar op til halvanden Meter. 
En aarlig periodisk Variation 1 Havstrømmenes Be- 
vægelse finder rimeligvis Sted i de øverste Lag. De dy- 
bere Lag ere ikke underkastede nogen saadan, ifølge Zöp- 
pritz Undersogelser*. Vindenes fStyrke er 1 Nordhavet 
betydelig større om Vinteren end om Sommeren, og Luft- 
trykkets Minimum befinder sig altid ude over Havet?. 
Derimod er den fra Elvevandet og Sne- eller Issmeltning 
hidrørende Forhøjelse af Havniveauet under Kysterne bety- 
delig større om Sommeren end om Vinteren. I hvilken 
Udstrækning disse Aarsager opveje hverandre, faa! kom- 
mende Undersøgelser afgjøre. 
Havstrømmenes Virkning paa de Landes Klima, som 
de berøre, er en anerkjendt Kjendsgjerning. Her kun en 
1 Wiedemanns Annalen, III. 4. 
I @ 8, GOI, 
Zeitschrift der österreiehisehen Gesellschaft fiir Meteorologie, 
1884, April, m. Kart. 
S. 582. 
ro 
met with in a few places, nay at Station 52 (max. of temp.) it 
exceeds 45 per cent. The very trifling amount of lime met 
with in the tract north-east of Jan Mayen, may come, not only 
of the great distance traversed from the Atlantic, but 
in part also of the Foraminifera shells sinking here in an 
ascending current, and being thus exposed for a considerable 
time to the dissolving action of the sea-water, After 
all, there would accordingly appear to be fair agreement 
between the organic deposits on the sea-bed and our cur- 
rent-system. 
According to Zöppritz," the current-system as now 
existing is the work of the winds during a period of se- 
cular extent. As I have sought to show, this work 
is brought about by the formation of a surface deviat- 
ing from the surface of level, partly by the direct action 
of the winds and the rotation of the earth, partly 
by the differences in the density of the sea-water, as 
maintained by the wind-currents and the river-water. As 
regards the effect of the normal winds, evaporation, and 
precipitation after the current-system has become con- 
stant, this consists in maintaining the current-surface, and 
along with it the current-system. The normal winds are 
the result of the normal distribution of atmospheric pres- 
sure, which in turn depends on the distribution of tem- 
perature. But this is dependent to a very great extent 
on the temperature of the sea and the distribution of land 
and water. Thus we come to the heat of the sun, the 
conformation of land and sea, and the rotation of the earth 
as principal factors in determining climate, atmospheric 
pressure, temperature, evaporation, precipitation, winds, and 
ocean-currents. 
Any changes in these fundamental conditions will in- 
volve changes in the currents of the ocean, which may 
exert a great influence on climate. Secular changes in the 
relative sea-level at the coasts, cannot be explained, it would 
seem, in this way, since the greatest height of the current- 
surface above the surface of level through the deepest point 
of the sea-surface reaches only a metre and a half. 
An annual periodic variation in the motion of ocean- 
currents takes place in all probability throughout the upper- 
most strata. The deeper strata are not subjected to such 
variation, according to Zéppritz’ investigations.” The force 
of the winds in the North Ocean is considerably greater 
in winter than in summer, and the minimum of atmospheric 
pressure lies invariably out at sea.” On the other hand, 
the rise of the sea-level in immediate proximity to the 
coasts, occasioned by river-water and the melting of snow 
or ice, is much greater in summer than in winter. To what 
extent these causes counteract each other, it must rest with 
future investigations to determine. 
The influence of ocean-currents on the climate of 
countries with which they come in contact, is a well-known 
1 Wiedemanns Annalen, III, 4, p. 582. 
3 øl jo COI, 
5 Zeitschrift der österreichisehen Gesellschaft fiir Meteorologie, 
1884, April, with Chart. 
