Note 3 — Chapter V · ON THE ORIENTATION AND MEASUREMENTS OF ZIMBABWE RUINS.

There is nothing to show that even these walls do not belong to a now far distant time; for although they would not long remain in this country, yet at Zimbabwe they might endure for an indefinite period, for there, in a clear atmosphere free from dust, and a tropical climate with its yearly torrential rains, no soil can accumulate among the stones to support vegetation which would destroy the walls. The few small plants which grow even on the oldest walls are of species which do not require much mineral matter for their growth, and whose roots are so soft that they mould themselves to the shape of the interstices in the walls, but do not press asunder the stones. Besides, the present inhabitants of the country do not use stone in any of their constructions, and never trouble themselves to remove stones from any existing walls, so that more stones have probably been disturbed during the two years of British occupation of the country than the Kaffirs would disturb in as many centuries; and under the old conditions the walls might endure for an indefinite time.3