It would naturally be expected from these observations, that less rain
falls on high ground than at the level of the sea. Such however is not
the case, except on abrupt elevations; where the elevation is made by the
natural and gradual slope of the earth's surface, the quantity of rain is
greater on the mountain than in the plain. Thus, on the coast of
Lancashire, there is an annual fall of 39 inches; while at Easthwaite,
among the mountains in the same county, the annual depth of rain amounts
to 86 inches. By comparing the registers at Geneva and the convent of
the Great St. Bernard, it appears that at the former place, by a mean of
thirty-two years, the annual fall of rain is about 30.75 inches; while at
the latter, by a mean of twelve years, it is a little over 60 inches.

In order to explain these remarkable differences, it must not be supposed
that the clouds extend down to the ground, so as to cause more rain at
the foot of Westminster Abbey than on its roof. There is no doubt that
in moist weather the air contains more water near the ground than a few
hundred feet above it; and probably, the same cause which determined a
fall from the cloud, would also throw down the moisture floating at a low
elevation. Much rain also proceeds from drifting showers, of short
duration, and the current moves more slowly along the surface, and allows
the drops to fall as fast as they are formed. In hilly countries, on the
contrary, clouds and vapours rest on the summits without descending into
the plains, and, according to some, the hills attract electricity from
the clouds, and thus occasion rain to fall. Mr. Phillips supposes that
each drop of rain continues to increase in size from the commencement to
the end of its descent, and as it passes successively through the moist
strata of the air, obtains its increase from them; while the rain which
falls on the mountain may leave these moist strata untouched, so that
they may, in fact, not form rain at all.

The drops of rain are of unequal size, as may be seen from the marks made
by the first drops of a shower upon any smooth surface. They vary in
size from perhaps the twenty-fifth to a quarter of an inch in diameter.
It is supposed that in parting from the clouds they fall with increasing
speed, until the increasing resistance of the air becomes equal to their
weight, when they continue to fall with an uniform velocity. A
thunder-shower pours down much faster than a drizzl