232 SEVENTH REPORT—1837, 
Atmospheric tides.—There are four tides of the atmosphere 
in Dukhun, as indicated by the movement of the barometer ; 
two diurnal, and two nocturnal: the diurnal rising tide is from 
4—5 a.m. to 9—10 a.M., and varies from ‘0200 inches to ‘0500 
inches; the falling tide is from 9—10 a.m. to 45 p.m, and 
varies from *1950 inches to ‘0150 inches. The nocturnal 
rising tide is from 4—5 p.m. to 10O—11] P.m., and varies from 
0450 inches to 1140 inches; the nocturnal falling tide is 
from 10—11 p.m. to 4—5 a.o., and is about :0442 inches. This 
order was never deranged or inverted in one single instance 
in many thousand observations. 
Temperature.—The climate of Dukhun is subject to very 
considerable variations of temperature ; more, however, in the 
diurnal than in the monthly or annual ranges; indeed, less so 
in the last particular than in Europe. In 1827, the extreme 
range of the thermometer at Edmonton was 75° Fahrenheit ; 
at Cheltenham, 64°°6. In St. Petersburgh, the thermometer 
has been as low as 35°°7! below zero, and as high as 91°4; 
the range, therefore, 127°:1, At Berne, the annual range has 
been more than 75°. In 1826, I observed a range of 53°4, 
viz., from 93°°9 on the 12th March, to 40°-50 on the 15th 
January at sunrise. In 1827, the maximum range observed by 
me was 48°°8, viz., from 96°°8 on the 28th March, to 48° on 
the 12th December at sunrise. In 1828, the maximum oc- 
curred on the 7th May, being 101°, and the minimum was 56°, 
the range, therefore, 45°; but, for a very short time, the ther- 
mometer rose on the 7th May, between two and three o’clock, 
to 105°; and this was the more remarkable as I was then en- 
camped on the edge of the Ghats at the source of the Beema 
river, at an elevation of 3090 feet above the level of the sea. 
This instance of unusual height of the thermometer, however, 
is not confined to Dukhun, for we learn from M. Arago, that it 
has been higher than 101° Fahrenheit in the shade in Paris. 
Monthly means.—The monthly means do not differ more 
than from 13° to 17° from each other. In 1826, the dif- 
ference between the hottest month (May, 83°:28), and the 
coldest (January, 65°-90), was only 17°38. And in 1829, 
March was the hottest month, and November the coldest, ° 
their difference of means being 15°°66. 
Diurnal range.—The greatest diurnal range in 1826 was 
on the 5th March, being 37°°30, from 50°°5 to 87°8. In 1827, 
it was 39°°5, on the 12th December, from 49°°5 to 89°. In 
1828, it was 34°°8, on the 16th July, from 56° to 90°°8. In 
1829, the maximum diurnal range was 37°°5 in December. 
The minimum diurnal range occurs in the monsoon months of 
