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14
METEOROLOGY OF GREENWICH IN 1867.
The mean temperature of the year was 48.°6, which is 0.2 of a degree
higher than the mean of 98 preceding years, but 0.07 lower than themean
of 27 years. The mean daily range of temperature was 15.06, or 0.04 less
than the averange of 27 years. The rain-fall measured 28.4 inches, which
is 0.8 of an inch more than the average of 52 years.
The first quarter was 0.07 colder, the second quarter was 0.06 warmer
the third quarter was 0.03 cooler, the fourth quarter of the year was 2.05
colder than the corresponding quarters of 26 previous years.
The mean daily amount of horizontal movement of the air was 283
miles, which is more than any year since 1848. To sum up, there was
nothing very notable in the general meteorogical conditions. The chief
differences from the means of other years were a lower temperature of the last
three months of the year, and a greater amount of wind throughout the year.
The general temperature, the rain-fall, and the degree of moisture which
prevailed was very nearly what has been noted in previous years.
REPORT ON THE GAS SUPPLY DURING THE YEAR 1867.
The average illuminating power during the whole year, at the time of
my testings, on 144 different days, was equal to 14.2 standard candles. (On
each occasion ten observations were made and the average taken). The
mean of the monthly maximum results was 15.2, and the mean of the
monthly minimum results was 13.4 candles. The highest illuminating
power observed was 15.6, and the lowest was 12.1 candles.
Traces of ammonia were detected by turmeric test-papers almost constantly
; the gas was on all occasions free from indications of sulphuretted
hydrogen. The amount of sulphur in the gas varied on different occasions,
from 7 grains to 16.3 grains in 100 cubic feet. On no occasion during the
year was the amount found to exceed the limit defined by the Act. The
mean of all the testings was about 10 grains to the 100 feet of gas.