s effect in tempering the heat of the lowlands, especially
at night. If tropical mountains are high enough, they carry snow all the
year round, even on the equator, and the zones of vegetation may range
from the densest tropical forest at their base to the snow on their
summits. The highlands and mountains within the tropics are thus often
sharply contrasted with the lowlands, and offer more agreeable and more
healthy conditions for white settlement. They are thus often sought by
residents from colder latitudes as the most attractive resorts. In
India, the hill stations are crowded during the hot months by civilian
and military officials. The climate of many tropical plateaus and
mountains has the reputation of being a "perpetual spring." Thus on the
interior plateau of the tropical Cordilleras of South America, and on
the plateaus of tropical Africa, the heat is tempered by the altitude,
while the lowlands and coasts are very hot. The rainfall on tropical
mountains and highlands often differs considerably in amount from that
on the lowlands, and other features common to mountain climates the
world over are also noted.

_The Characteristics of the Temperate Zones._

_General._--As a whole, the "temperate zones" are _temperate_ only in
that their mean temperatures and their physiological effects are
intermediate between those of the tropics and those of the polar zones.
A marked changeableness of the weather is a striking characteristic of
these zones. Apparently irregular and haphazard, these continual weather
changes, although they are essentially non-periodic, nevertheless run
through a fairly systematic series. Climate and weather are by no means
synonymous over most of the extra-tropical latitudes.

_Temperature._--The mean annual temperatures at the margins of the north
temperate zone differ by more than 70 deg.. The ranges between the mean
temperatures of hottest and coldest months reach 120 deg. at their
maximum in north-eastern Siberia, and 80 deg. in North America. A
January mean of -60 deg. and a July mean of 95 deg., and maxima of over
120 deg. and minima of -90 deg., occur in the same zone. Such great
ranges characterize the extreme land climates. Under the influence of
the oceans, the windward coasts have much smaller ranges. The annual
ranges in middle and higher latitudes exceed the diurnal, the conditions
of much of the torrid zone thus being exactly reversed. Over much of the
oceans of the temperate