st 
hour og en Hastighed af 4 til 23 miles. Heraf beregnes 
ke) to) c=) ? 
at Vindstyrken 3.9 svarer til 22.5 miles an hour. Da 1 
mile an hour svarer til 0.447 Meter pr. Secund, faar man 
Vindstyrke 3.9 = 10.0 Meter per Secund, 
altsaa: til en Vindhastighed af 10.0 m. p. 8. 
Stromhastighed af 15 Kvartmil 1 24 Timer eller, idet 
vi sætte Stromhastigheden proportional med Vindhastig- 
heden, å 
Vindhastighed 1 m. p. S. giver Strømhastighed 1.5 Kvart- 
mil i 24 Timer eller 0.082206 Meter pr. Secund {log 
0.032206 = 8.50794). 
Man har i den senere Tid gjort Indvendinger mod 
Rigtigheden af Scotts Reductionstabel, der hovedsagehg gaa 
i den Retning, at den til en vis Vind-Styrke svarende Ha- 
stighed skulde være mindre end den, Scotts Tabel angiver. 
svarer en 
Saalænge Discussionen om denne Sag ikke har faaet nogen 
bestemt Afslutning, har jeg fundet at burde holde mig til 
Scotts Tabel, saameget mere, som de samme Data, der ere 
benyttede til at udlede Stromhastighedsfactoren, tidligere! have 
ledet til en særdeles god Overensstemmelse mellem den efter 
Scotts Tabel beregnede Vindhastighed og den af Barome- 
terhøjderne paa dynamisk Vej Den af Gra- 
dienten beregnede Vindhastighed var nemlig 9.15 m. p. S., 
medens den af den observerede Vindstyrke efter Scotts Tabel 
udledede var 9.38 m. p. S. Forskjellen, 0.25 m., peger 1 
samme Retning som ovenfor bemerket og antyder en For- 
mindskelse, dog kun af 2.5 Procent. En Formindskelse af 
de respective Vindhastigheder vilde forøvrigt give Vinden 
en forholdvis større Evne til at fremkalde Strøm. 
beregnede. 
Den Maade, hvorpaa Vinden virker paa den med Is 
dækkede Del af Havet, er en anden end den, hvorpaa den 
virker paa det aabne Hav. For det første svækkes selve 
Vindens Styrke, som vi ovenfor have seet, ved at den blæser 
over Isen, og dernæst har Vinden at sætte i Bevægelse 
directe selve Isen og gjennem dens Bevægelse middelbart 
Vandet. Da Havisen frembyder en yderst ujevn saavel 
Overflade som Underflade og kan paa sine Steder stikke 
temmelig dybt, maa man vente, at Vindens Virkning til at 
sætte et isfyldt Hav i Bevægelse resulterer i en langsom- 
mere Fart, end naar Havet er isfrit. For at faa et Maal 
for denne Virkning, med andre Ord, for at finde Strømfac- 
toren for det isfyldte Hav har jeg benyttet Sir Leopold 
M‘Clintock’s Observationer fra *Fox”s Drift i Baffins-Bugt 
og Davis-Strædet Vinteren 1857—58. Efter 
man følgende Tabel, i hvilken Vindstyrken (den observe- 
rede, altsaa af Isen paavirkede) er angivet etter Beaufort 
Skala, Driftens Retning efter den Compasstreg, henimod 
hvilken den fandt Sted, og Driftens Hastighed i Kvartmil 
disse har 
horizontalen Luftströme in der 
Nahe des Æquators. Von C. M. Guldberg und H. Mohn. Zeitschrift 
der gsterreichischen Gesellschaft fiir Meteorologie 1877, S. 182. 
Tallet 9.15 er beregnet efter de til Normaltyngden reducerede Baro- 
meterhøjder. 
' Ueber die Bewegung der 
corresponds to a velocity of 18 miles an hour, and a velocity 
of 4 to 23 miles. From these figures was computed, that a 
wind-force of 3.9 corresponds to 22.5 miles an hour. As 
1 mile an hour corresponds to 0.447 metre per second, 
we get — 
Force of wind 3.9 = 10.0 metres pr. second; 
hence, to a wind-velocity of 10.0 m. per second  corre- 
sponds a current-velocity of 15 nautical miles in 24 
hours, or, putting the current-velocity proportional to 
the wind-velocity, 
a wind-velocity of I m. per second gives a current-velocity 
of 1.5 nautical miles in 24 hours, or 0.032206 metre 
per second {log 0.032206 = 8.50794). 
Of late objections have been made to Scott's Table 
of Reduction, which conclude in assuming the velocity cor- 
responding to a given force of wind as less than given in 
Scott’s Table. 
has not attained a definite conclusion, I have seen fit to 
So long as the discussion on this subject 
abide by Scott’s Table, more especially since the same data 
that have been used for educing the factor for current veloc- 
ity, on a former occasion led to excellent agreement between 
the velocity of wind computed according to Scott’s Table 
and that dynamically. The 
computed from the gradient was namely found to be 
computed wind-velocity 
9.15 m. per sec., whereas that deduced from the observed 
force of the wind according to Neott's Table was 9.38 m. 
per sec. “The difference, 0.23 m., points in the same direc- 
tion, as remarked above, and indicates a decrease, but of 
only 2.5 per cent. Besides, a diminution of the respective 
wind-velocities would give the wind a proportionally greater 
power to produce currents. 
The way in which the wind acts on the ice-covered 
part of the sea, is another compared to its action on the 
open water. To begin with, the force of the wind itself 
is materially weakened, as shown above, by blowing over 
ice; and in the next place, the wind has to impart motion 
directly to the ice, and through that motion indirectly to 
the water beneath it. Sea-ice presenting an exceedingly 
rough surface, both the upper and the under, and reaching 
in places a considerable depth, we cannot but expect that the 
power of the wind to set in motion an ice-encumbered sea 
should result in a slower rate than with a sea free of ice. 
To obtain a standard for this influence, or, in other words, 
to find the current-factor for an ice-encumbered sea, I made 
use of Sir Leopold M‘Clintock’s observations from the drift 
of the “Fox” in Baffin’s Bay and Davis Strait during the 
winter 1857—58. From these we have the following Table, 
in which the force of the wind (viz., the observed, or that 
to Beaufort 
Scale, the direction of the drift by the point of the com- 
influenced by the ice) is given according 
1 Ueber die Bewegung der horizontalen Luftstr6me in der Nahe 
Von C. M. Guldberg und H. Mohn. Zeitschrift der 
1877, p. 182. The 
figures 9.15 have been computed from the heights of the barometer 
des Æquators. 
österreichischen Gesellschaft fir Meteorologie, 
reduced to normal gravity. 
