and continues till near six in the evening. About seven
the land-breeze comes off, and prevails through the night till towards
eight in the morning, when it gradually dies away.

CAUSE OF THE LAND AND SEA-BREEZES.

These depend upon the same general principle that causes and regulates
all other wind. Heat acting upon air rarefies it, by which it becomes
specifically lighter, and mounts upward. The denser parts of the
atmosphere which surround that so rarefied, rush into the vacuity from
their superior weight; endeavouring, as the laws of gravity require, to
restore the equilibrium. Thus in the round buildings where the
manufactory of glass is carried on, the heat of the furnace in the centre
being intense, a violent current of air may be perceived to force its way
in, through doors or crevices, on opposite sides of the house. As the
general winds are caused by the DIRECT influence of the sun's rays upon
the atmosphere, that particular deviation of the current distinguished by
the name of land and sea breezes is caused by the influence of his
REFLECTED rays, returned from the earth or sea on which they strike. The
surface of the earth is more suddenly heated by the rays of the sun than
that of the sea, from its greater density and state of rest; consequently
it reflects those rays sooner and with more power: but, owing also to its
density, the heat is more superficial than that imbibed by the sea, which
becomes more intimately warmed by its transparency and by its motion,
continually presenting a fresh surface to the sun. I shall now endeavour
to apply these principles. By the time the rising sun has ascended to the
height of thirty or forty degrees above the horizon the earth has
acquired, and reflected on the body of air situated over it, a degree of
heat sufficient to rarefy it and destroy its equilibrium; in consequence
of which the body of air above the sea, not being equally, or scarcely at
all, rarefied, rushes towards the land and the same causes operating so
long as the sun continues above the horizon, a constant sea-breeze, or
current of air from sea to land, prevails during that time. From about an
hour before sunset the surface of the earth begins to lose the heat it
has acquired from the more perpendicular rays. That influence of course
ceases, and a calm succeeds. The warmth imparted to the sea, not so
violent as that of the land but more deeply imbibed, and consequently
more permanent, now acts in turn, an