ON THE CONTINUOUS
X
CURRENTS
WHICH THE
BODIES
TIDAL ACTION OF THE HEAVENLY
MUST PRODUCE IN THE OCEAN.
(Verhandlungen der physikalischen Gesellschaft zu Berlin, 5th January 1883.)
IN
consequence of the friction of the water of the sea, internal
as well as against its bed, the tidal skin whose axis in the
absence of friction would lie in the direction of the tide-gener-
ating body or in a perpendicular direction, will be turned
through a certain angle out of the positions named. Hence
the attraction of the tide-generating body on the protuberances
of the tidal ellipsoid gives rise to a couple opposed to the
earth's rotation. The work done by the earth against this
couple as it keeps rotating is that energy at whose expense
the tidal motion is continually maintained in spite of the
friction. It would be impossible to transfer to the solid
nucleus of the earth this couple, which directly acts on the
liquid, if the motion of the liquid relative to the nucleus were
purely oscillatory, and if the mean ocean level coincided with
the mean level surface. The transference becomes possible
only because the mass of liquid constantly lags a little behind
the rotating nucleus; or because there is a continual elevation
above the mean level at the western coasts of the ocean; or
because both phenomena occur together. I have attempted to
deduce from the theory of the
estimate of the character and
currents generated in this way.
tion are as follows.
motion of a viscous fluid an
order of magnitude of the
The results of the investiga-
Consider a closed canal. Let be the distance along it
from the origin, L its whole length, h its depth, t the time,