etter at afvige til Højre lodret paa Bevægelsens Retning. 
Maalet for denne Bestræbelse, udtrykt som accelererende 
Kraft, er 
2 ov sin —p %, 
hvor w er Jordens Omdrejnings Vinkelhastighed 
27:86164 = 0.00007292 (se ovenfor Side 114), m den 
geografiske Bredde. 
Idet Vandpartikkelen p samtidig paa- 
virkes af Tyngden pg, som betegnes ved 
g, kommer Resultanten pr af Tyngden 
og den ved Jordrotationen fremkaldte Af- 
bøyningskraft ph til at danne en Vinkel 
med Tyngdens Retning. Havoverfladen 
00 vil stille sig lodret paa denne Resul- 
tant, og altsaa danne en Vinkel » med 
Niveaufladen ph. Vandets Overflade lof- 
ter sig til hojre, naar man ser frem i den 
Retning, 1 hvilken det bevæger sig. I 
denne skraa Flade er der Ligevægt, naar 
ph 
Tyngden, g, er forskjellig 
beregnes efter Formelen 
for forskjellige Bredder, og kan 
, g = gas (1—pP cos 2 g) 
J 45 = 9.806165 og 8 = 0.00259 *. 
Vinkelen 1 bliver altid meget liden. For en Strom- 
hastighed af 4 Kvartmil i 24 Timer eller 0.09 Meter per 
Secund bliver den kun 4 Secund, og dens højeste Verdi 1 
Nordhavet bliver % Secund. 
Ved ovenstaaende Beregning af Havoverfladens Skraa- 
hed have:vi kun taget Hensyn til Jordrotationens Afbgj- 
ningskraft som den eneste i horizontal Retning virkende 
Kraft. Foruden denne virke ogsaa Centrifugalkraften, 
Frictionen og Tregheden ?. 
Frictionen ved Vandets Bevægelse langt fra Kysterne 
og Bunden er kun den indre Friction mellem Vandtraade, 
der betinges af de til hverandre grændsende Traades for- 
skjellige Hastighed. 
hvor 
Denne Forskjel er yderst ringe, og vi 
kunne sætte Frictionens Virkning ud af Betragtning i For- 
hold til Afbøjningskraften. 
Ogsaa til Trægheden tage vi intet Hensyn, idet over 
store Strækninger Strømmens Hastighed praktisk taget er 
uforandret. I Constructionen af Vind-Strøm-Systemet er 
taget Hensyn til Vandets jevne [Bevægelse over længere 
Strækninger i Modsætning til Vindens. 
Centrifugalkraftens Virkning bliver ogsaa meget ringe, 
og saagodtsom forsvindende i Forhold til Virkningen af 
1 0. J. Broch. Accéleration de la pesanteur ete. 
2 Se Guldberg og Mohn, Etudes sur les mouvements de bat- 
mosphére, I, S. 19, og Zeitschrift der dsterreichischen Gesellschaft 
fir Meteorologie, 1877, S. 258. 
cos 7 = pg sin 7; 2osin 4. u. cos 9 = g sin 7; tang 7 
124 
a tendency to deviate towards the right, perpendicular to 
the direction of its motion. The measure of this tendency, 
expressed as accelerating force, is 
2 osin fu, 
in which w represents the angular velocity of the earth’s 
rotation, 27: 
latitude. 
86164 = 0.00007292 (See p. 114), p the 
Now, the particle of water, p, being 
also acted upon by gravity, pg (gravity I 
designate g), the resultant, pr, of gravity 
and the deviating force, ph, arising from 
the earth’s rotation, will form an angle, 
y, with the direction of gravity. The sur- 
face of the sea, 0 0, will assume a position 
perpendicular to this resultant, and ac- 
cordingly form an angle, 7, with the sur- 
face of level. ph. The surface of the 
water rises upon the right when looking 
in the direction in which it moves. In 
this inclined surface there is equilibrium, 
when 
2 sin g 
GONG . U. 
g 
The force of gravity, g, is different for the different lati- 
tudes, and admits of being computed by the formula 
g = 9 (1—P cos2y), 
Q45 = 9.800165 and 8 = 0.00259. 
The angle 1 will always be very small. For a cur- 
rent-velocity of 4 nautical miles in 24 hours, or 0.09 metres 
per second, it will amount to only I second; and its highest 
value in the North Ocean does not exceed % second. 
In our computation set forth above of the inclination 
of the sea-surface, we had regard merely to the deviating 
force of the earth’s rotation, as the only force acting in a 
horizontal direction. Besides, we have also centrifugal force, 
friction, and inertia exerting their influence. ? 
Friction attending the motion of the water far away 
from the coasts and the bed of the sea, is only the inner 
friction between threads of water caused by the different 
velocities of adjacent threads. Such difference is trifling 
in the extreme, and the effect of friction may be wholly 
set aside compared to that of the deviating force. 
Of inertia likewise we take no account, since the ve- 
locity of the current, regarded practically, will continue 
unchanged throughout extensive tracts. When constructing 
the wind-current system, consideration was had to the uni- 
form motion of the water over long tracts of ocean as 
contrasted with that of the wind. 
The effect of centrifugal force is also exceedingly limited, 
nay well-nigh inappreciable compared to the effect of the 
in which 
1 O. J. Broch. Accéleration de la pesanteur ete. 
2 See Guldberg and Mohn, Etudes sur les mouvements de ’at- 
mosphére, I, p. 19; and Zeitschrift der dsterreichischen Gesellschaft 
fiir Meteorologie, 1877, p. 258. 
