THE METEOROLOGY OF THE PLAINS AND MOUNTAINS OF N. W. INDIA. 
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Txovcn the Meteorology of a country is frequently omitted in Works treating of Natural History, 
there is no subject which is more interesting or more closely connected with its several branches, especially 
when it is desired to point out the connection between climate and the vegetable and animal forms 
which it supports. ‘This is still more important, indeed essentially necessary, when we desire to make 
any Practical application to the Arts of Culture of the results of our investigations into the Natural 
History of a country. 
India being so extended in territory and varied in surface, with lengthened coasts, washed by a tro- 
pical ocean, and the summits of its mountains, covered by eternal snows, necessarily presents every variety 
of climate. As it is intended in the present Work to notice the vegetation of its heated plains and vallies, 
and to compare this with that found on the slope of its mountains, it is desirable, therefore, for the sake 
of comparison, to notice the more striking characteristics of the climate of different parts of India. This 
can only be done very briefly ; but the Author hopes to be able to return to the subject, and give the 
details of his observations made at Saharunpore, from the year 1826 to 1830, with the Barometer, 
and both the Dry and Wet Bulb Thermometer, with observations on Radiation, Temperature of Wells, 
Quantity of Rain, together with Horary Observations, with all the instruments, from 1 a.m. to midnight, 
or for one day (the 15th) in each month for one year; occasionally also at different elevations, and at 
the different seasons of the year, in the Himalayan Mountains. 
The instruments were compared with those of Capt. Herbert and of Mons. Jacquemont, when these 
gentlemen passed through Saharunpore, and subsequently with those of my friend Mr. James Prinsep, 
on my arrival in Calcutta, and the differences between all were very slight. 
As much of the vegetation of India is of a tropical nature, and as this is found extending into higher 
latitudes, or to considerable elevations, when local circumstances favour the production of a similar climate, 
we may therefore notice the characteristics of tropical climate, which consist in great uniformity of tem- 
perature, as well as of moisture, throughout the year. Various attempts have been made to ascertain by 
calculation the mean temperature of the Equator, assisted by the few observations which we possessed, 
of places in its vicinity. The illustrious Humboldt was induced to adopt 81° 5’ as the mean tempera- 
ture of the Equator. Mr. Atkinson, on the contrary, inferred, that it was at least 84° 53’; but when 
it is considered that five-sixths of this line passes over the Ocean, the mean temperature of which between 
the limits of 3° N. and 3° S. varies, in general, between 80° 24 and 82° 4/, and as the air which rests 
upon these waters is from 1° 8’ to 2° 7 cooler, it is probable that 81° 5’ is not too low for the mean 
temperature of the Equator. Sir David Brewster, indeed, from observations since made in Ceylon, 
Penang, and at Singapore, is inclined to think that this may be too high. 
_ The seasons in equatorial regions are well known to be characterized by great equability of tempera- 
ture, and, in fact, they are not distinguished, as in high latitudes, into hot and cold, but into wet and 
_ dry seasons, and are greatly regulated by the periodical winds. In Java and Sumatra the thermometer 
= ———- 85° or 90° on the coast, falling as low as10° at sunrise. The heaviest rains take place 
in December and January, the driest weather occurs in July and August, while the intermediate months 
_ afford variable weather. Singapore, from its insular nature, and being 1° 15’ North of the ‘Equator, 
~— near the S. extremity of the Malayan Peninsula, is well suited to give an idea of an Equatorial 
— there we have, fortunately, thermometric observations carried on for six years by Capt. C. E. 
Davis, three times a-day: at 6 a.m., 6 p.m., and at Noon (v. Journ. As. Soc. 2, p. 428), though the 
a . mean temperature deduced from them may probably be a little too high; but in the whole time the 
Thermo- 
