The relative position of the land and water is an essential cause of
this diversity. The waters of the ocean are of very equal temperature,
and have a tendency to moderate both heat and cold, wherever their
influence extends. Thus when a cold wind passes over the sea, it becomes
warmed, while a hot wind becomes cooled; and thus islands generally
experience milder winters and more temperate summers than continents.
Such countries are said to possess an insular climate. But when any
region experiences great severity of cold in winter and a high degree of
heat in summer, it is said to possess an extreme or excessive climate.
The most striking instances of an extreme climate are drawn from places
like Yakutsk, situated in the depths of Siberia, where the difference
between the average temperature of winter and summer amounts to the
astonishing sum of 101 degrees Fahrenheit.
[Illustration: =THE LIFE-GIVING SUN SENDING HEAT AND LIGHT=
The sun is the great life-giver of our earth. Its waves of light and
heat and electricity come to the earth through a measureless ocean of
ether and make it a living rather than a dead world. The above
illustration shows how these waves are constantly bombarding the earth,
and not only giving it life but contributing to it the glory of the
seasons, the wonders of color, and the brilliant effects of light which
we see in the skies and call Auroras, or Northern and Southern Lights.]