View report page

For the purpose of the third control, started on the 11th September, 406 entrances were
baited and the recorded result was 31 "takes" (7 complete, 5 x ¾, 3 x ½ and 16 x ¼). In this
instance 6 bodies were found.
The equivalent control of the first series resulted in 18 "takes" (4 complete, 4 x ¾, 8 x ½
and 2 x ¼) ex 396 entrances treated.
The fourth and final control of the series was applied on the 5th December and of a total of
399 entrances baited 29 "takes" were obtained (8 complete, 3 x ¾, 9 x ½ and 9 x ¼) as against
17 "takes" (4 x ¾ and 13 x ½) and 4 and 10 bodies respectively were found.
The annual overall test was applied as from the 1st January, 1959, 22 days after completion
of the final control of the second series and a total of 400 manholes were baited, and on examination
21 complete "takes" were recorded as opposed to 27 "takes" (15 complete, 9 x ¾,
1 x ½ and 2 x ¼) in the comparable test on completion of the first series of Controls.
The third series of 4 "direct" controls at quarterly intervals is due to start in June, 1959
and will follow an overall test baiting after a lapse of six months, which will again provide data
on the build-up during this period.
In conclusion it is understood that the results of this series of controls on a full scale and
under practical conditions, coincide with results of experiments conducted by the Scientific
Officers of the Infestation Division, Ministry of Agriculture, Fisheries and F'ood.
From observations of the Fluoracetamide, "1.081" controls and comparison of the detailed
records collected, it does appear to be comparable to Mono Sodium Fluoracetate, "1080".
Bearing in mind the complete "takes" of poison bait obtained in both series, it might well be
more palatable than the latter, and this, when combined with slower onset of warning symptoms
results in a larger bait acceptance.
By reason of its coarser division it is safer to dispense and owing to lower toxicity to rats
and presumably to man, is less hazardous in distribution.
ATMOSPHERIC POLLUTION
1958 was the third complete year of the coming into operation of the smoke abatement
provisions of the City of London (Various Powers) Act, 1954, and the second of the Clean Air
Act, 1956. No application was received under Section 4 (2)(b) of the Various Powers Act for
approval to use, in existing premises, a fuel other than one of those on the list of "authorised"
fuels. Mr. City Engineer had three such applications in respect of new buildings which were
subsequently approved by the Public Health Committee. Three notices of intention to install
or replace furnaces in existing premises were received. In each case the fuel to be used was an
"authorised" fuel under the Various Powers Act. Complaints of smoke emission relating to six
premises were made by the general public. All were of a temporary nature and were remedied by
suitable administrative action.
During the year steam railway locomotives became subject to Regulations which specify the
periods when emissions of smoke of prescribed densities will be allowed. The problem of smoke
and grit emissions from steam traction diminished as a result of the replacement of a number of
steam locomotives by modern diesel units. By June, 1959 this improvement will be more
apparent by the greater use of diesel cars on some services and the electrification of others at
Liverpool Street and Moorgate, but not until 1960/61 (the electrification of the London, Tilbury
and Southend Section of the Eastern Region will be completed by then) will the full impact begin
to be felt of the modernisation programme of the British Transport Commission. Meanwhile
every effort is being made to secure supplies of low volatile fuel, and by frequent visits of the
railway supervisory staff to ensure that smoke emissions are reduced to a minimum.
In a contribution by members of the Department of Scientific and Industrial Research to the
Conference in October of the National Society for Clean Air, the results of a survey of air
pollution in London and its smokeless zones, indicated the probability of a 40 per cent reduction
in average smoke pollution over much of the City of London, which more nearly agrees with the
calculated figure of a maximum, at the centre, of 58 per cent. It has often been said that air
pollution does not stop at local boundaries and that the air of a smokeless zone surrounded by
smoky neighbours would be swamped by their emissions so that there would be no appreciable
local benefit. The result of the survey should provide some encouragement to authorities who
may be considering embarking on smoke control areas under the Clean Air Act. Of dust and
grit deposition and sulphur dioxide emission it was concluded, as the result of the survey, that
the measurements showed no reduction. In fact, in 1958, the water-insoluble matters i.e., dust
and grit deposited in the gauges at Golden Lane and Guildhall were much in excess of that
found in 1957 and for the average of the preceding 5 years. This is quite understandable having
regard to the large scale re-development of war damaged sites, and much of the deposited matter
is due to the demolition of old, and the erection of new , buildings. On the other hand the weight
of tarry matter — a water-insoluble constituent closely associated with the emission of chimney
smoke — is considerably less than the average for the preceding five years.
13