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Chemicals, drugs and medical supplies of various types were submitted for
analysis and report, and also lubricating and other oils, floor and tile polishes and
silver plate polishes. Many of these were to L.C.C. specifications and the need for
keeping these up to date, having regard to recent scientific advances and the
improvement in the supply position, was constantly borne in mind. In this connection,
it should be added that the use of modern insecticides (based on D.D.T. and
Gammexane) for the various purposes continued with satisfactory results. The
development of synthetic detergents was carefully watched and the use of one type
(which previous experimental trials had proved to be the most satisfactory) was
continued on a large scale for hand washing-up : the newly developed production of
these as spray-dried powders has some advantages. Disinfectants were examined as
to their germicidal value, stability of emulsion and freedom from staining linen
fabrics.
Swimming bath waters and drinking water supplies at residential schools were
examined and the work on school meals already described was done indirectly for
this service. Modelling plastics suggested for use in schools were analysed, and also
coloured chalks: some of these were reported on adversely as containing deleterious
colouring ingredients (lead chromate, antimony compounds). Instructional visits of
school parties to both the Headquarters and Northern Outfall Works laboratories
might also be mentioned.
Much consultative and advisory work was done for both the Chief Engineer's
and Architect's departments involving examinations in situ and subsequent analysis
of samples in the laboratory regarding scale formation, scale removal and corrosion
problems. The use of sodium hexa-metaphosphate for scale prevention, and of soda
ash and quebracho or full phosphate conditioning for boiler water was considerably
extended. The dosages were controlled by periodical analysis of the water concerned.
Examples of special cases dealt with were — (a) several cases of severe
scaling were successfully dealt with by the adoption of the hexa-metaphosphate or
micromet treatment; for example, in a series of electrically heated tea boilers:
(b) extensive corrosion of iron pipes having occurred at some out county premises
the installation of copper pipes was recommended having regard to the nature of
the water supply and other circumstances.
At the request of the Architect this matter was dealt with extensively in 1949.
The most important case was Cleopatra's Needle. The last full treatment of this
was in 1911 and on re-examination it was found that the wax then used had
crystallised in plates and the deposited dirt had penetrated behind it on to the
stone; there was also some evidence of flaking of the stone. After laboratory
investigation and bearing in mind the need for care to avoid further injury to the
stone and the inscribed hieroglyphics, the treatment adopted was first of all to
soften the wax and dirt with a mixture of carbon tetrachloride and benzole and
then to emulsify and remove it by the use of a non-ionic synthetic detergent. A low
melting point paraffin wax dissolved in white spirit was applied and the wax
subsequently carefully melted into the stone by means of a blow lamp. This
effectively sealed the microscopic fissures, preventing the ingress of water.
Other monuments, etc., dealt with were Boadicea's Statue, several commemorative
plaques, and ceremonial bronze doors. Each case had to be considered
separately as to the best method which could be devised for its particular
circumstances and material.
Many other matters were dealt with of which may be mentioned: (a) The death
of fish in an ornamental pond was attributed to the effect of a violent storm of
rain in hot weather which disturbed the mud at the bottom and caused the
depletion of the dissolved oxygen content of the water: (b) an investigation was
made into the possibility of installing simple instruments for measuring the consumption
of hot water in separate flats whose supplies are drawn from a central
Education
Steam
raising, heating,
etc.,
plants
Cleaning of
Monuments,
etc.
Miscellaneous