4 
ON THE STATISTICS OF DUKHUN. 231 
Sedimentary Rocks.—There are not any sedimentary rocks 
in Dukhun, nor am I aware of any south of Broach, excepting 
such as have probably originated in the consolidation of com- 
paratively recent alluvium. 
Climate. 
A detailed account of the atmospheric tides, and meteor- 
ology of Dukhun having been published in the Philosophical 
Transactions, I shall limit myself to a description of such broad 
features as characterize the climate. The Ghats and the 
Desh have distinct features. The tract along the line of the 
former has a lower mean temperature, much more moisture, 
greater prevalence of westerly winds, a more limited range of 
the thermometer; but a greater prevalence of fogs before, 
during, and after the rains, but not in the winter months ; 
and, finally, is characterized by the absence of hot winds. 
The Desh, on the contrary, has the air excessively dry in the 
hot months; a great diurnal and annual range of the ther- 
mometer, a comparatively small fall of rain in the monsoon, 
the frequent occurrence of hot winds, and the rareness of 
fogs. 
iiatometer.—'The mean monthly pressure of the atmosphere 
is greatest in the winter months of December and January ; it 
gradually diminishes until July or August, the most damp 
months, when it is at its minimum; it gradually increases again 
until the cold months. The greatest diurnal oscillation re- 
corded by me in several years’ observations was *1950, or less 
than two-tenths of an inch; the smallest oscillation ‘0150. The 
mean rise of the barometer from sunrise to 9—10 a.m. for three 
years was ‘0445, thermometer + 7°15’. The mean fall from 
9—10 a.m. to 4—5 p.M., for four years, was ‘1066, thermometer 
+ 5°21’; and the mean rise from 4—5 a.m. to 10—11 p.o., for 
one year, is ‘0884, thermometer — 7°°2’. The maximum range 
_ of the barometer at Poona, in the year 1830, at 1823 feet 
above the sea, was only ‘672, or not seven-tenths of an inch. 
The mean height of the barometer for that year was 27°-9254, 
and the mean height in the monsoon was 27°°8447; so that the 
constant moisture of the monsoon only occasioned a mean 
diminution of pressure of ‘0807, or less than one-tenth of an 
inch. At Madras, for twenty-one years, the mean height of 
the barometer was 29°-958! inches ; at Calcutta, the means of 
three years make it 29°764. M. Arago, at Paris, by nine 
years’ observations, reduced to the level of the sea, makes the 
_mean height 29:9546 inches, being almost identical with the 
mean height at Madras. 
