508 
WHIRLWINDS; AND CLOUDS OF SAND. 
3—13 Jan. 
straight, nor were they quite perpendicular; but uncertain and 
changing. Whenever thej happened to pass over our fire, all the 
ashes were scattered in an instant, and nothing remained but the 
heavier sticks and logs. Sometimes they were observed to disappear, 
and, in a minute or two afterwards, to make their re-appearance at 
a distance further on. This occurred whenever they passed over 
rocky ground, or a surface on which there was no dust, nor other 
substances sufficiently light to be carried up in the vortex. Some- 
times they changed their color, according to that of the soil or dust 
which lay in their march ; and when they crossed a track of country 
where the grass had lately been burnt, they assumed a corresponding 
blackness. 
But to-day the calm and heat of the air was only the prelude 
to a violent wind ; which commenced as soon as the sun had sunk, 
and continued during the greater part of the night. The great heat, 
and long-protracted drought of the season, had evaporated all mois- 
ture from the earth, and rendered the sandy soil excessively light 
and dusty. Astonishing quantities of the finer particles of this sand 
were carried up by the wind, and filled the whole atmosphere ; 
where, at a great height, they were borne along by the tempest, and 
seemed to be real clouds, although of a reddish hue; while the 
heavier particles, descending again, presented, at a distance, the 
appearance of mist or driving rain. 
During the day, I had been employed in preparing the skin of 
the large blue crane ; but the scorching beams of a nearly vertical 
sun caused a violent head-ache and throbbing at the temples. The 
remedy which was always found efficacious in such cases was strong 
tea taken very warm ; the power of which, assisted by wrapping up, 
particularly the head, caused an active perspiration, that, in the 
course of the evening, relieved the pain and removed all symptoms. 
But by degrees, as I became more inured to exposure to the sun, I 
rarely suffered any serious attack of this kind. 
8^A. The heat of this day also was intense, and almost insup- 
portable. The thermometer, however, did not rise above 96° ; but 
there was not a breath of air stirring. In the rainy climate of 
