This Is The Same Phenomenon, On A Gigantic Scale, As That
Which Takes Place On Table Mountain, At The Cape, In What Is Called
The Spreading Of The "Table-Cloth".
The southeast wind causes a mass of air,
equal to the diameter of the mountain, suddenly to ascend
at least
Three thousand feet; the dilatation produced by altitude,
with its attendant cold, causes the immediate formation of a cloud
on the summit; the water in the atmosphere becomes visible;
successive masses of gliding-up and passing-over air cause the continual
formation of clouds, but the top of the vapory mass, or "table-cloth",
is level, and seemingly motionless; on the lee side, however,
the thick volumes of vapor curl over and descend, but when they reach
the point below, where greater density and higher temperature
impart enlarged capacity for carrying water, they entirely disappear.
Now if, instead of a hollow on the lee side of Table Mountain,
we had an elevated heated plain, the clouds which curl over that side,
and disappear as they do at present when a "southeaster" is blowing,
might deposit some moisture on the windward ascent and top;
but the heat would then impart the increased capacity
the air now receives at the lower level in its descent to leeward,
and, instead of an extended country with a flora of the `Disa grandiflora',
`gladiolus', `rushes', and `lichens', which now appear on Table Mountain,
we should have only the hardy vegetation of the Kalahari.
Why there should be so much vegetation on the Kalahari may be explained
by the geological formation of the country.
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