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55
Explosive
properties of
anesthetics.
In connection with an inter-departmental conference on the dangers of explosion
in operating theatres, the explosive properties of some anaesthetics have been
investigated. It has been found that mixtures of ethyl chloride and air are explosive,
within fairly wide limits, an objectionable product of the explosion being hydrochloric
acid. Mixtures of oxygen and ether, as delivered from apparatus used in operating
theatres, are violently explosive, and the addition of chloroform cannot be relied
on to inhibit explosion. The source of ignition in these experiments, which were
undertaken in view of the extensive use of electrical appliances in operating theatres,
was a spark from a Ruhmkorff coil.
Fertilisers
and feeding
stuffs.
In connection with the provisions of the fertilisers and reeding btuns Act,
1926, 282 samples have been examined during the year under the supervision of
the chemist who is the agricultural analyst for those parts of the county which do
not come under the purview of the City Corporation or, Port Sanitary Authority.
The results of the analyses were :

The figures are very similar throughout to those of last year, though the number
of samples with no guarantee or one incorrect in form shows some increase, thus
emphasising the need for continued supervision of the conditions of sale of these
commodities.
It is remarkable that the apparently very wide limits of variation from the
guaranteed composition which are allowed under the Act should so often be exceeded
in the direction of supplying a better article than that stipulated.
Flue gases.
Flue gases have also been examined from time to time at Abbey Mills pumping
station and at Woolwich ferry in connection with the efficient burning of fuel for
steam raising.
Boiler waters.
The regular examination of the water before and after softening has been
undertaken at County Hall and the pumping stations, thus ensuring a suitably
softened water and more efficient and economical working of the boilers.
River
Wandle.
A sample of water taken by a brewery for cooling purposes was obtained for
examination as to its suitability for return into the river Wandle. Investigation
showed that the water was of the same general character as the water of the river
and, moreover, that the effluent was not returned to the river, but flowed into the
sewer.
Swimming
bath water.
In consequence of complaints of the deposition of a green slime (algae) on the
glazed tiles of the indoor swimming bath at the Hutton residential school, an addition
(when the bath was filled) of 1 lb. of chloride of lime to 65,000 gallons of water was
found to be effective.
The waters of several open-air swimming baths have been examined as to their
freedom from suspended matter (green growths, etc.) and advice given as to the
desirability of treatment or emptying.
Water supply
—private
wells.
The transfer of many institutions to the Council under the Local Government
Act, 1929, caused a large increase in the amount of work in the examination of
the water supply from private wells. Daring the year such supplies at 37 institutions
were examined, a total of 208 samples being analysed. In eight of these cases advice