EXCESSIVE HEAT. 
97 
picture,?” He could not, in fewer words, have given me an .insight 
into the whole of his feelings upon this subject. 
From the 28th to the 31st May, the heat was excessive, the ther¬ 
mometer at about two o’clock, in our different tents, varying from 98° 
to 103°. The Persians allowed this heat to be uncommon, but still 
talked of it as trifling when compared with the great heats of summer. 
Although it was very oppressive, yet we did not find it so relaxing as 
the heat of India. All our furniture had suffered extremely : maho¬ 
gany boxes that had stood the climate of India, and which had crossed 
the equator several times unwarped, here cracked. Ivory split, our 
mathematical rulers curled up, and the mercury in the artificial horizons 
over-ran the boxes which contained it. We found the nights cool, 
and the mornings quite cold, the thermometer varying sometimes 30° 
between the greatest heat and the greatest cold. The difference was 
sufficiently sensible to enable us to comprehend the full force of the 
complaint which Jacob made unto Laban : —In the day the drought 
consumed me, and the frost by night. Gen. xxxi. 40. 
During the day-time a light breeze generally prevailed from the 
westward. It is to be remarked, that when there was a perfect calm, 
partial and strong currents of air would arise and form whirlwinds, 
which produced high columns of sand all over the plain. * Those that 
,we saw at Shiraz were formed and dissipated in a few minutes, nor is 
it the nature of this phenomenon to travel far, it being a current 
of air that takes its way in a capricious and sudden manner, and is dis¬ 
solved by the very nature of its formation. They are looked upon as 
the sign of great heat, which was indeed the case, because they never 
took place but when the heavens were quite calm. Their strength was 
very various. Whenever one of them took our tents, it generally dis¬ 
turbed them very materially, and frequently threw them down. Their 
appearance was that of water-spouts at sea, and perhaps they are pro¬ 
duced in the same manner. 
We learnt from three English gentlemen (the Rev. Mr. Martyn, 
* Compare Bruce’s Account of the Pillars of Sand in the Desert, vol. iv. c. xi. p. 563. 
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