ON THE METEOROLOGY OF BIRMINGHAM. 299. 
4, Dew-point (Tables XVI. XVII.).—The dew-point register extends over 
five years, from 1838 to 1842 inclusive. The Table XVI. shows the monthly 
and annual means as derived from observations made daily at 9 a.m. and 
3 P.M. with Daniell’s hygrometer. 
’ The mean annual dew-point from Table XVI. is 44°95, while the same 
result deduced in Table XVII. from the highest and lowest monthly dew- 
_ point at the above-mentioned hours is 44°18. 
: Adopting the first quantity, 44°95, the mean annual dryness of the climate 
of Birmingham is 4°95, and its mean humidity (complete saturation being 
represented by unity) is =0°707 ; and consequently the weight of vapour in 
a cubic foot of air is =3°03 grs., and the quantity required for saturation 
about 1°28 gr. 
5, Evaporation (Table XVIII.).—The amount of evaporation is recorded 
_ for two years only, namely, 1843 and 1844; and was registered daily at 9 a.m., 
by Howard’s evaporation gauge, which was placed 37 feet above the ground. 
In 1843 the greatest amount took place in the months of June, July and 
August, and the least in February ; while in 1844 the greatest amount took 
~ place in the months of May, June and July, and the least in December. 
: The total amount of evaporation was, for 1843, 32°166 in., and for 1844, 
_ 85°113 in. 
6. Winds (Tables XIX. XX.).--The Table XIX. records the direction of 
the winds at 9 a.m., through the several months of the years 1837 to 1844 
inclusive; Table XX. being a summary of the aggregate number of the 
several winds throughout that period, with the corresponding barometric 
_ pressures, reduced to 32°, with their variations from the mean. The mean of 
_ the barometric pressures at 9 A.M. was 29°403 in.; differing only by +°014 in. 
from the mean of the observations at 9 a.m. and 3 p.m.; and the forces, as 
shown by the pressures, balance each other to the hundredth of an inch. 
The prevailing winds at Birmingham are from the S.W., S., and S.S.W. in 
- the order indicated. Of 2914 registered winds, not fewer than 906, or nearly 
one-third, blew from those quarters alone; namely, from the S.W. 341, from 
_ the S. 300, and from the S.S.W. 265. 
_ It is an anomalous fact, of which I do not understand the cause, that the 
_ barometer is lower with the S.E. than with the S.W. winds, the mean pres- 
& 
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— sure with the S.E. winds being 29°191, and with the S.W. winds 29347. 
~ Conelusion.—In the synoptical Table XXT. the meteorological elements of 
~ temperature, pressure, and dew-point, during the five years for which the 
“materials of comparison exist, are brought into juxtaposition; and in the ap- 
pended curves (Plate V.) these elements are represented graphically. sila 
It is not my intention to enter into any enumeration or discussion of the 
_ Many interesting deductions suggested by the before-mentioned tables. I 
_ May, however, remark, in general, that they exhibit some important results 
in comparison with similar tables constructed from data derived from other 
~ localities, and show a marked difference between the climate of the south- 
western and other parts of our island and its interior; and illustrate, more- 
over, the influence of situation and local circumstances, even at moderate 
distances, in modifying the general laws of climate, and their influence on 
human health, longevity, and enjoyment. 
_ The striking accordance of form between the accompanying curves and 
‘similar ones formed by numerous observers, from facts obtained at different 
~and widely separated places, is strongly corroborative of the simplicity, 
uniformity, and universality of the laws by which the great agencies of me- 
teorologic change are restrained from destructive irregularity and excess, 
~ and controlled and adjusted, with the nicest exactness, to the exigences of 
animal and vegetable existence. ; Ti 
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