hat is the case. And for the first
moment it seems absurd; for what then makes the summer hotter than the
winter? That is due to an altogether different cause; it depends on the
position of the earth's axis. If that axis were quite straight up and
down in reference to the earth's path round the sun we should have equal
days and nights all the year round, but it is not; it leans over a
little, so that at one time the North Pole points towards the sun and at
another time away from it, while the South Pole is pointing first away
from it and then toward it in exactly the reverse way. When the North
Pole points to the sun we in the Northern Hemisphere have our summer. To
understand this you must look at the picture, which will make it much
clearer than any words of mine can do. The dark part is the night, and
the light part the day. When we are having summer any particular spot on
the Northern Hemisphere has quite a long way to travel in the light, and
only a very short bit in the dark, and the further north you go the
longer the day and shorter the night, until right up near the North
Pole, within the Arctic Circle, it is daylight all the time. You have,
perhaps, heard of the 'midnight sun' that people go to see in the North,
and what the expression means is that at what should be midnight the
sun is still there. He seems just to circle round the horizon, never
very far above, but never dipping below it.

When the sun is high overhead, his rays strike down with much more force
than when he is low. It is, for instance, hotter at mid-day than in the
evening. Now, when the North Pole is bowed toward the sun, the sun
appears to us to be higher in the sky. In the British Isles he never
climbs quite to the zenith, as we call the point straight above our
heads; he always keeps on the southern side of that, so that our shadows
are thrown northward at mid-day, but yet he gets nearer to it than he
does in winter. Look at the picture of the earth as it is in winter.
Then we have long nights and short days, and the sun never appears to
climb very high, because we are turned away from him. During the short
days we do not receive a great deal of heat, and during the long night
the heat we have received has time to evaporate to a great extent. These
two reasons--the greater or less height of the sun in the sky and the
length of the days--are quite enough to account for the difference
between our summer and winter. There is one rather inter