opic of Capricorn
raises hopes for a rich economic, social and cultural development here;
but these are dashed by an examination of the isotherms. Excessive heat
lays its retarding touch upon everything, while a prevailing aridity
(rainfall less than 10 inches or 25 centimeters), except on the narrow
windward slope of the eastern mountains, gives the last touch of
climatic monotony. The coastal belt of Cape Colony and Natal raise
tropical and sub-tropical products[1431] like all the rest of the
continent, while the semi-arid interior is committed with little
variations to pastoral life. [See maps pages 484 and 487.] Climatic
monotony, operating alone, would have condemned South Africa to poverty
of development, and will unquestionably always avail to impoverish its
national life. South African history has been made by its mines and by
its location on the original water route to India; the first have
dominated its economic development, and the latter has largely
determined its ethnic elements--English, Dutch, and French Huguenots,
while the magnet of the mines has drawn other nationalities and
especially a large Jewish contingent into the urban centers of the
Rand.[1432] In the background is the native Kaffir and Hottentot stocks,
whose blood filters into the lower classes of the white population. The
diversity of these ethnic elements may compensate in part for the
monotony of climatic conditions, which promise to check differentiation.
However, climatic control is here peculiarly despotic. We see how it has
converted the urban merchants of Holland and the skillful Huguenot
artisan of France into the crude pastoral Boer of the Transvaal.

In contrast to South Africa, temperate South America has an immense
advantage in its large area lying outside the 20 deg.C. isotherm, and in the
wide range of mean temperatures (from 20 deg.C. to 5 deg.C.) found between the
Tropic of Capricorn and Tierra del Fuego. Climate and relief have
combined to make the mouth of the La Plata River the site of the largest
city of the southern hemisphere. Buenos Ayres, with a population of over
a million, reflects its large temperate hinterland.

[Sidenote: The effects of Arctic cold.]

Frigid zones and the Tropics alike suffer from monotony, of Arctic the
one of cold and the other of heat. The Arctic climatic belt, extending
from the isotherm of 0 deg.C. (32 deg.F.) to the pole, includes inhabited
districts where the mean annual temperature is l