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62
atic analyses for a variable treatment of the tidal water used at the Western Pumping
Station have led to a great improvement in the condition of the boilers. The
great advantage of treatment at an elevated temperature has been demonstrated
by experiments made in the laboratory.
Systematic examination of water in the various stages of steam-raising has
assisted in the efficient working of both pumping stations and sludge ships; similar
work has been done at the outfall laboratories.
Coroners
inquests—
Poisoning.
Toxicological investigations have again been made at the request of medical
officers in charge of certain of the Council's institutions. A case of peculiar
interest was that of an inmate of a mental hospital who was found dead in
her bed. Yew poisoning was suspected and vegetable structures found in the
stomach contents were isolated and found to be morphologically indistinguishable
from authenticated yew leaves. The toxic constituent of yew does not appear
to be well characterised chemically, but the deadly properties of the leaves and
stems of taxus baccata are well known.
Bathing
lakes and
open-air
swimming
baths.
The supervision, as set out in previous reports, has been continued in connection
with the outdoor swimming baths in the Council's parks. The fine weather led to
a much greater use of these baths and in these conditions the very great advantage
of filtration and chlorination were manifest. It has been found that the use by the
bath attendants of simple chemical tests, after careful instruction, enabled the use
of the necessary chemicals to be sufficiently controlled. Chlorination effected some
improvement in the water of the baths not fitted with filtering plant, but it is impossible
to keep these in the same satisfactory condition as to appearance, purity or
safety as those with filters.
Petroleum
Acts.
The examination of samples collected by inspectors under the Pretroleum Acts
has shown that new materials are being largely used as solvents for paints, varnishes
and " dopes." Among these may be mentioned methylcylohexanone, a member
of a class of bodies which has been prominently exhibited in recent years at the
British Industries Fair.
River Lee.
The River Lee, which was inspected on two occasions in July, continues to be
objectionable in the parts which flow through or by the County of London. The
main cause of this condition appears to be the heavy pollution of the Pymmes Brook
and the intercepting ditch which receives the contents of the Brook and passes them
into the Lee below Tottenham Lock. Below this point the Navigation Cut is dirty
with a scummy surface. The water bubbles vigorously and smells unpleasantly
whilst scum accumulates around moored boats. Chemical analysis shows this water
to be poorly aerated and highly contaminated although there is some self-purification.
The very small flow in this canalized part of the river allows the accumulation of
foul matters to settle on the river bottom so that the water itself does not show the
full effect of pollution. The natural stream which runs more or less alongside the
Navigation Cut is in a rather more satisfactory condition.
fiiver
Wandle,
This river was visited towards the end of July, at Earlsfield, where the effluents
from the Wandle Valley Sewage Board Works and the Wimbledon works enter.
The water of the river after receiving these effluents is used by the Southern Railway
for circulation in the condensers at their electricity works. The effluents
appear to be well purified, and the effect of cascading in the condensers and return
channel was on the whole beneficial as, at the time of examination, the water below
the outfalls was better aerated than that above.
River
Thames.
The systematic examination of the River Thames was continued in 1928 at
points from the Edinburgh Lightship to Waterloo Bridge. The results obtained in
the early summer were considered to justify the partial use of chemical precipitants
for a short period. Some improvement occurred as the summer went on, owing to
an increase in the fresh water flow, and the additional treatment was stopped. The
results obtained at the upper stations in the summer, show that the effects due