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and ascertain the carbon monoxide content. Many samples of bread were analysed
under the Bread (Control and Maximum Prices) Order, 1947, to determine whether
the short weight supplied was due to the bread being either "fancy bread" or "protein
fortified." In cases where this was not so, legal proceedings were attended by an
officer of the Chemical Branch to support the certificate given. Premises of firms of
dry cleaners working under licence were visited periodically and samples of the
atmosphere in the machines were taken for subsequent analysis to ensure that the
safety regulations regarding the limitations of inflammable gases, derived from
volatile solvents, were being duly observed.
Chemical analyses and bacteriological examinations of the water of swimming
baths were made and the chlorine dosage being applied for sterilisation purposes was
checked, recommendations for any necessary alteration of procedure being made as
required. During the bathing season all water used in the Council's public swimming
baths is chemically treated, filtered and chlorinated, and, at the majority of the baths,
the so-called " breakpoint " system of chlorination is used. This consists of adding a
relatively large dose of chlorine which rapidly destroys the polluting nitrogenous compounds
: the excess of chlorine above the breakpoint is less likely to cause inconvenience
to bathers than smaller doses well below it. Plants capable of such dosage
are moreover more flexible and can be adjusted to deal with sudden heavy loading in
hot weather. The water of natural ponds used for bathing was also tested and many
samples of soil were analysed as to their content of plant nutrient substances.
Parks
The materials examined for this service cover a very wide field and include a
number actually dealt with for some of the other services mentioned above : for
example, certain paints, and also foodstuffs used by the Restaurants and Catering
Department. Foods of all types, in fact, form a considerable proportion of the work
under this heading and they were examined (a) as tendered samples to ascertain
which offer gave the best value for money, (b) from bulk supplies to ensure that these
were to the standard of the tendered sample and (c) any complaints from consumer
services. Generally a high standard of quality was maintained with but few complaints.
Some of the materials offered for tender were, however, not satisfactory,
certain ice creams for example, being very low in fat content even down to 0.5 per
cent. in one case. Particular watch was kept on the question of the use of petroleum
in foodstuffs, but in only one case (the material was not accepted for use) was it
present in quantity. Canned foods were carefully watched particularly in regard to
the corrosion of the containers and the tin (metal salt) content of the food. Many
samples of liquid milk were examined and also dried milk, the latter particularly in
regard to the acid value and the possibility of curdling dishes in the preparation of
which it may be used. Chemicals, drugs and medical supplies of various types were
submitted for analysis and report, and also lubricating and other oils, and floor and
tile 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 the modern insecticides D.D.T. and Gammexane in suitable
formulations for the different 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. An investigation was made on
anti-freeze solutions for motor car engine radiators with particular reference to the
prevention of corrosion : the use of sodium benzoate as an inhibitor was recommended.
Disinfectants were examined as to their germicidal value.
Supplies
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: one was
Education