The friction of the wind combines with the tide in agitating the
surface of the ocean, and, according to the theory of undulations,
each produces its effect independently of the other. Wind, however,
not only raises waves, but causes a transfer of superficial water
also. Attraction between the particles of air and water, as well
as the pressure of the atmosphere, brings its lower stratum into
adhesive contact with the surface of the sea. If the motion of the
wind be parallel to the surface, there will still be friction, but the
water will be smooth as a mirror; but if it be inclined, in however
small a degree, a ripple will appear. The friction raises a minute
wave, whose elevation protects the water beyond it from the wind,
which consequently impinges on the surface at a small angle: thus
each impulse, combining with the other, produces an undulation which
continually advances.--_Mrs. Somerville’s Physical Geography._