21. Desert Sands

If deserts _have_ a fault (which their present biographer is far from
admitting), that fault may doubtless be found in the fact that their
scenery as a rule tends to be just a trifle monotonous. Though fine in
themselves, they lack variety. To be sure, very few of the deserts of
real life possess that absolute flatness, sandiness and sameness, which
characterises the familiar desert of the poet and of the annual
exhibitions--a desert all level yellow expanse, most bilious in its
colouring, and relieved by but four allowable academy properties, a
palm-tree, a camel, a sphinx, and a pyramid. For foreground, throw in a
sheikh in appropriate drapery; for background, a sky-line and a
bleaching skeleton; stir and mix, and your picture is finished. Most
practical deserts one comes across in travelling, however, are a great
deal less simple and theatrical than that; rock preponderates over sand
in their composition, and inequalities of surface are often the rule
rather than the exception. There is reason to believe, indeed, that the
artistic conception of the common or Burlington House desert has been
unduly influenced for evil by the accessibility and the poetic adjuncts
of the Egyptian sand-waste, which, being situated in a great alluvial
river valley is really flat, and, being the most familiar, has therefore
distorted to its own shape the mental picture of all its kind elsewhere.
But most deserts of actual nature are not all flat, nor all sandy; they
present a considerable diversity and variety of surface, and their rocks
are often unpleasantly obtrusive to the tender feet of the pedestrian
traveller.

A desert, in fact, is only a place where the weather is always and
uniformly fine. The sand is there merely as what the logicians call, in
their cheerful way, 'a separable accident'; the essential of a desert,
as such, is the absence of vegetation, due to drought. The barometer in
those happy, too happy, regions, always stands at Set Fair. At least, it
would, if barometers commonly grew in the desert, where, however, in the
present condition of science, they are rarely found. It is this dryness
of the air, and this alone, that makes a desert; all the rest, like the
camels, the sphinx, the skeleton, and the pyramid, is only thrown in to
complete the picture.

Now the first question that occurs to the inquiring mind--which is but a
graceful periphrasis for the present writer--when it comes to examine in
detail the peculiarities of deserts is just this: Why are there places
on the earth's surface on which rain never falls? What makes it so
uncommonly dry in Sahara when it's so unpleasantly wet and so
unnecessarily foggy in this realm of England? And the obvious answer is,
of course, that deserts exist only in