the forest is confined to the deep valleys or the mountain-slopes. The
rainfall, which is fair on the coast, becomes very light in the middle
belt, which in consequence tends to have an arid character; on the
plateau it is high or very high. Because of these marked differences the
economic character of the three regions varies considerably.
Semi-tropical products, such as maize, coffee, cotton, and millet, can
be raised on an almost unlimited scale on the plateau; while rice,
rubber, sisal, and copra are raised in the two lower belts.

[Sidenote: The chain of large lakes.]

[Sidenote: Extinct and active volcanoes.]

All along the mountains which mark the western edge of the high plateau
one will notice a chain of lakes, from Nyasa in the south through
Tanganyika and Kivu to Lake Albert in the north. In prehistoric time
some convulsion of nature broke the African continent all along its
spine, and formed this system of lakes. Another break occurs on the high
plateau, from Portuguese East Africa in the south to British East Africa
in the north, along the Great Rift Valley, with its magnificent
escarpments and weird scenery, prolonged through Lake Rudolf to the Red
Sea and on to the Dead Sea and Jordan Valley. Great volcanoes, now
mostly extinct, though some to the north of Kivu are still active, are a
still later feature of the country.

[Sidenote: Lakes and mountains a frontier for defense.]

I have referred to these lakes and to the great mountain-chain along the
lakes because they formed the western boundary of German East Africa,
and from the point of view of defense made a magnificent frontier so