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bromide and carbon tetrachloride under the conditions of test can produce acid
vapours of such a concentration as would be dangerous in an enclosed space unless
a mask were worn. Although carbonyl chloride (phosgene) and carbonyl bromide
were not found in appreciable quantity, the possibility of their formation under
special circumstances must be borne in mind. In order to extinguish a fire with
carbon dioxide it appears that a concentration of this gas is required which must
be regarded as a possible danger in a confined space unless a mask is worn : the
time required to extinguish a fire by this means is also longer than when using methyl
bromide. The final opinion expressed was that there is no more risk involved in the
use of methyl bromide and carbon tetrachloride extinguishers than when carbon
dioxide alone is used. In each case it would be necessary to use a mask if the fire
were in a confined space.
During the year, 92 samples, taken under the Petroleum (Consolidated) Act,
1928, and London County Council (General Powers) Act, 1912, were examined.
Of these, 22 samples were petroleum spirit as defined by the Act; 49 samples contained
petroleum spirit and came under the provisions of the Act; and 21 samples
were not, or did not contain, petroleum.
Petroleum
Act
A sample of a white cotton material was submitted which showed irregularly
distributed thin patches and holes. An examination of the article showed that
although the material was quite strong generally, the fibres were badly damaged
in places, and there was evidence that borates had been used in the process of
washing. It seemed probable that a washing powder containing sodium perborate
had been used in a manner resulting in an uneven distribution in the washing
machines. Recent work has shown that unless these bleaching materials are used
under proper conditions, serious damage to fabrics is likely to be caused.
Laundry
work
Much discussion has taken place in professional circles, and many papers have
been published on the question of the effect of sulphates in water or subsoil, on
Port land-cement concrete. The matter has been investigated during the year, and
work is still being continued in connection with one of the Council's housing estates
where the clay has been found to contain a small amount of sulphuric anhydride
present as soluble sulphates, and also appreciable quantities of pyritic matter
and selenite which may cause damage to Portland-cement concrete especially in the
presence of water. A sample of water from this site was found to contain soluble
sulphate considerably in excess of that found in normal surface water.
Concrete
In accordance with an order of the Entertainments Committee, arrangements
were made for the examination of the atmosphere in several places of public entertainment,
and a report was submitted thereon from the hygienic point of view.
The conclusion was that the average "cinema" without mechanical aids to reasonable
ventilation, was not well ventilated, and that "theatres" without mechanical
yentilation, were definitely unsatisfactory from this point of view. One particular
hall, in which alterations to the ventilating system were subsequently made, was
re-examined later in the year. Considerable improvement was evident and the
atmospheric conditions were then described as satisfactory.
i Places of
entertainment
:
ventilation
In addition to the applied research which has been necessary to elucidate many
of the problems submitted by other departments during the year, it has been found
possible to carry out several pieces of what may be termed "pure" research work.
These have been found necessary in connection with the critical examinations of
'analytical processes available for the testing of products used by the Council, and
include the determination of small quantities of strychnine in the presence of caffeine,
the colorimetric determination of morphine, and the determination of the best
method for estimating cod-liver oil in preparations of this substance. By the aid
of the quartz spectrograph mentioned above, an investigation has been begun as
to the possible loss in course of manufacture or storage of the vitamin A content of
cod-liver oil in extract of malt and oil.
Research