“On my route from Suez to Cairo,” says Rüppel, “I had an opportunity of
observing a meteorological phenomenon of a very curious nature, which
possibly may lead to some interesting results. In the year 1822, May the
21st, being seven hours distant from Cairo, and in the desert, we were
overtaken by one of those violent winds from the south, about which many
travellers have told us such wonderful and incredible stories. During
the night there had been a light breeze from the north-east; but a short
time after sun-rise it began to blow fresh from the S.S.E., and the wind
gradually increased till it blew a violent storm. Clouds of dust filled
the whole atmosphere, so that it was impossible to distinguish any
object clearly as far off as fifty paces; even a camel could not be
recognised at this distance. In the mean time, we heard all along the
surface of the ground a kind of rustling or crackling sound, which I
supposed to proceed from the rolling sand that was dashed about with
such fury by the wind. Those parts of our bodies which were turned
towards the wind were heated to an unusual degree, and we experienced a
strange sensation of smarting, which might be compared with the pricking
of fine needles. This was also accompanied by a peculiar kind of sound.
At first I thought this smarting was occasioned by the small particles
of sand being driven by the storm against the parts of the body that
were exposed. In order to judge of the size of the particles, I
attempted to catch some in a cap; but how great was my surprise when I
found I could not succeed in securing a single specimen of these
supposed little particles. This led me to conceive that the smarting
sensation did not proceed from the small stones or the sand striking the
body, but that it must be the effect of some invisible force, which I
could only compare with a current of electric fluid. After forming this
conjecture, I began to pay closer attention to the phenomena which
surrounded me. I observed that the hair of all our party bristled up a
little, and that the sensation of pricking was felt most in the
extremities and joints, just as if a man were electrified on an
insulated stool. To convince myself that the painful sensation did not
proceed from small particles of stone or sand, I held a piece of paper
stretched up against the wind, so that even the finest portion of dust
must have been detected, either by the eye or the ear; yet nothing of
the kind took place. The surface of the paper remained perfectly unmoved
and free from noise. I stretched my arms out, and immediately the
pricking pain in the ends of my fingers increased. This led me to
conjecture that the violent wind, called in Egypt Camsin, is either
attended by strong electrical phenomena, or else the electricity is
caused by the motion of the dry sand of the desert. Hence we may account
for the heavy masses of dust, formed of particles of sand, which, for
several days, darken the cloudless sky. Perhaps we may also go so far as
to conjecture that the Camsin may have destroyed caravans by its
electrical properties, since some travellers assure us that caravans
have occasionally perished in the desert; though I must remark that in
all the regions I have travelled through, I never could hear the least
account of such an occurrence. At all events, to suppose that such
calamities have been caused by the sand overwhelming the caravans, is
the most ludicrous idea that can be imagined.
“The Camsin generally blows in Egypt for two or three days successively,
but with much less violence during the night than the day. It only
occurs in the period between the middle of April and the beginning of
June, and hence its Arabic name, which signifies, ‘the wind of fifty
days.’”
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