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1
A. METEOROLOGY.
From the point of view of the weather, last year was a remarkable one, recalling in a
general way that of 1911. In Table I*, will be found the annual means, etc. of the principal
meteorological elements for the 11 years 1911-21, as observed at the Royal Botanical Gardens,
Regent's Park, together with the averages, etc. for the decennium 1911-20. The means of
the morning (9.0 a.m.) temperatures, wet and dry bulb thermometers, were higher last year
than in 1911 and in excess of the averages. In comparison with 1911 the means of the
past year were 2.1° and 0.2° higher. It will also be noted that the difference between the
readings—4.1°—was greater in 1921 than in 1911 or the averages for 1911-20. That
difference meant that the air was, on the average, drier during the past year. Last year
the highest temperature recorded was 930—a figure which was exceeded by 3° in 1911,
while the absolute minimum air temperature—25°—was 8° above the previous minimum
—17° in 1920. The maximum sun—black bulb thermometer—was 138°, a record not
exceeded during any of the preceding ten years, but equalled in 1914, a year of a different
character from last year. The minimum recorded by the grass thermometer was 19.7°, differing
notably from the minimum of 1920 (7.0°) and comparing favourably with the records of
the other years.
The total rainfall measured last year amounted to 14.55 inches, measurable quantities
being recorded on 116 days. In 1911 the total measured was 25.34 inches on 143 days,
the decennial average (1911-20) being 28.05, with measurable amounts on 164 days. A glance
at Table I will make the differences between the records very apparent.
As regards the record of bright sunshine, that for the past year is exceptional, the
year's total of 1561 hours—on 284 days—having been exceeded only by that of 1911, 1644
hours, on 267 days. In 1914 bright sunshine was recorded on 287 days, but the total
number of hours recorded was nearly 110 hours less.
While it has to be admitted that the effects on public health of a summer such as
that of last year, have not been fully worked out, it is possible to state that past experience
has shown that there is (or has been) a somewhat intimate connexion between high
temperatures of the air and soil, deficient rainfall, and infantile diarrhœa. At this
stage it will suffice to direct attention to the immediate effects of deficient rainfall and
high temperature and reserve comparisons of their influence on the prevalence of diarrhœa
for the section of this Report dealing with that disease. (See Diarrhœa, p. 26.)
The immediate effects just alluded to are—
from deficient rainfall—
(i.) Insufficiency of supply of water for domestic and municipal cleansing;
(ii.) Loss of cooling of the soil; and
from continued high temperatures—
(iii.) Promotion of decomposition in accumulations of refuse of all descriptions,
thereby favouring the breeding of flies and increased danger of spread
of infective material by those insects; and
(iv.) High temperatures in the upper layers of the soil.
Results (ii.)—(iv.) are important factors in the causation of diarrhoea, and while that
remark applies to result (i.), a shortage in the supply of water affects the public so generally
that a note on the question will be of sufficient interest to be included at this point. As some
90 per cent. of the Metropolitan supply is drawn from the Thames, data are available for a
direct estimation of the extent of the deficiency in the quantity of water from that source.
During the months of January and September of last year the rainfall measured was in
excess of the average.† The deficiencies observed in the other ten months varied from a
maximum of 95 per cent. of the average in July to a minimum of 15 per cent. in November.
For the whole year the deficiency was equal to 40 per cent. of the average, the year's total
fall amounting to 14.59 ins. and the average to 24.47 ins. The immediate effect of the
deficiency in rainfall on the river is clearly shown by the shrinkage in the quantity of water
measured as flowing over the weir at Teddington. In January the measurements showed
an excess equal to 27.7 per cent. of the month's average, the volume of water steadily
decreasing thereafter, until in December the flow showed a deficiency equal to 83 per cent. of
*All Tables will be found in the Appendix.
†The contents of this paragraph are based on records published in The Lancet of January 21st, 1922 (i., 1922,
p. 148). The averages here quoted are those for the 35 years 1881-1915.