ame condition, because, in
order to insure a good quality of the product, the bunches of grapes,
after picking, must be dried on the ground. To a certain extent this is
also true of other fruits, such as dates, figs, and prunes, which
frequently are sun-dried.

The presence of large bodies of water, which both absorb and give out
their heat very slowly, tempers the climate of the nearby land and to
that extent modifies the commerce of such districts. The grape-growing
industry of central New York is a great one and its product is famous.
Its existence depends almost wholly upon the lake-tempered climate.
Elsewhere in the State the industry is on a precarious basis, and the
product is inferior.

=Effects of Inclination of the Earth's Axis.=--The inclination and
self-parallelism of the earth's axis is undoubtedly a very important
factor in climate. Practically it more than doubles the width of the
belts of ordinary food-stuffs by lengthening the summer day in the
temperate zone. Beyond the tropics the obliquity of the sun's rays are
more than balanced by the increased length of time in which they fall.

Thus, in the latitude of St. Paul, the longest day is about fifteen and
one-half hours long; at Liverpool it is nearly seventeen hours long; a
greater number of heat units therefore are received in these latitudes
during summer than are received in equatorial regions during the
twelve-hour day. Moreover, the summer temperature is higher in these
latitudes than in the torrid zone, because the sun is shining upon them
for a greater length of time.

The result of these various influences is far-reaching. Because of the
long summer days and short nights, wheat can be cultivated to the
sixtieth parallel. Corn, which gets scarcely enough warmth and light in
the torrid zone to become a prolific crop, attains its greatest yield in
the latitude of fourteen-hour days.

These factors, it is evident, carry the grain and meat industries into
regions that otherwise would not be habitable. Because the long summer
days produce these great food-crops, commerce and its allied industries
have reached their maximum development in these regions. Human
activities are greatest in the zones bounded by the thirty-fifth and
fifty-fifth parallels, the zone that includes the greater parts of the
United States, Europe, China, Japan. They are greatest, moreover,
because of their geographical position.

QUESTIONS FOR DISCUSSION

What would be