London's Pulse: Medical Officer of Health reports 1848-1972
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Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
Holborn 1928
[Report of the Medical Officer of Health for Holborn Borough]
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TABLE VII.
METEOROLOGY OF LONDON 1928.
(Deduced from observations at Greenwich under the superintendence of the
Astronomer Royal)
| 1928. | Air Temperature. | Bright Sunshine. | Rain and other forms of Precipitation. | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Mean of— | Mean of A. & B. | Difference from Average." | Daily Mean. | Difference from Average.* | Per cent, of possible. | Total Fall. | Difference from Average.* | ||
| A. | B. | ||||||||
| Maximum. | Minimum. | ||||||||
| °F | °F | °F | °F | hrs. | hrs. | % | m.m. | m.m. | |
| January | 47.5 | 36.0 | 41.7 | +3.2 | 1.41 | +0.17 | 17 | 77 | +34 |
| February | 50.7 | 36.5 | 43.6 | +3.8 | 2.84 | +0.80 | 29 | 30 | -10 |
| March | 52.2 | 37.5 | 44.9 | +2.4 | 3.13 | -0.27 | 27 | 43 | -1 |
| April | 56.7 | 39.6 | 48.1 | +0.5 | 4.12 | -0.90 | 30 | 35 | -2 |
| May | 62.4 | 43.7 | 53.1 | +0.9 | 5.02 | -1.45 | 32 | 63 | +19 |
| June | 68.7 | 47.3 | 58.0 | -1.9 | 7.29 | +0.59 | 44 | 58 | +7 |
| July | 79.0 | 54.7 | 66.9 | -3.4 | 9.35 | +2.85 | 58 | 54 | -3 |
| August | 72.9 | 52.5 | 62.7 | +0.1 | 6.46 | +0.26 | 45 | 72 | +16 |
| September | 68.3 | 46.0 | 57.1 | -0.9 | 7.03 | +2.08 | 56 | 17 | -28 |
| October | 60.1 | 43.5 | 51.8 | +1.6 | 3.46 | +0.34 | 32 | 88 | +24 |
| November | 53.0 | 41.8 | 47.4 | -3.4 | 1.67 | -0.05 | 19 | 45 | -13 |
| December | 43.5 | 33.5 | 38.5 | -1.7 | 0.89 | -0.17 | 11 | 61 | +4 |
| Year | 59.6 | 42.7 | 54.1 | +1.0 | 4.39 | -0.34 | 33 | 643 or 25.07 ins. | + 47 or +l.83in. |
* L'lie averages used are obtained from observations extending over 35 years (1881-1915).
Ultra-Violet Rays.
Thanks to the work of Dr. Leonard Hill and others, figures are available
showing the amount of biologically-active ultra-violet rays present in London
and certain other towns throughout the year. The measurements are taken " by
the amount of fading produced in a standard solution of acetone and methylene
blue." The amount of fading of the solution at the end of 24 hours is
measured by comparison with a set of standard tubes numbered 10 to 3, of varying
depths of blue, fixed and unbleachable. The degrees of this colour scale are equal
and biologically standardised. One degree of the scale is equal to two to four
times the dose required to produce a slight sunburn, the sensitivity of the skin
varying in individuals. The particular wave length of ultra-violet rays which
are absorbed by and fade the acetone blue solution, closely correspond to those
which are active in producing sunburn of the skin and in activating ergosterol in
the skin and so forming vitamin D (antirachitic). The table following gives the
daily average for the various months in the year in some of the towns where
records are taken. It will be seen that Central London (Kingswa.y) and Hull show
low readings.
The figures show that the ultra-violet rays do not penetrate a smoky atmosphere
in sufficient quantities to be of practical value, and they lend weight to the
contention that the limited ultra-violet rays in town are often not used to the
greatest advantage. The majority of town dwellers spend the best hours of
daylight behind windows of ordinary glass, so that even the ultra-violet rays that
do penetrate the smoke laden atmosphere remain obscured to the indoor dweller
or worker. This condition would be improved by the more general use of glass
permeable to ultra-violet radiation. At the same time it should be understood that
the use of such glass would not make less urgent the need for every possible step to
be taken for the abatement and avoidance of smoke nuisances; the fact that ultraviolet
radiation is reduced by smoke in industrial areas is but an additional reason
why the small amount that does get through should be used to the greatest
advantage.
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