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147
Dr. Hartley's final conclusion is that " there is 110 chemical gas or
vapour of a dangerous kind present in appreciable amount" (p. 25 of
his report).
After a careful review of all the evidence, the number and locality
of complaints, and the investigations of Drs. Andrewes and Hurtley,
taken in conjunction with the fact that no definite case of illness has
ever been traced and recorded as due to sewer ventilating grids in the
middle of the road, your Committee has arrived at the conclusion
that no connection between the ventilators and disease has been proved,
and that it is extremely unlikely that such connection has existed or will
in the future exist.
On the other hand there can be no doubt that sewer smells are
diffused from the grids, and that, though not a nuisance dangerous to
health, they are still a nuisance.
Your Committee have therefore given much careful consideration
as to the means which may usefully be adopted to secure a prevention
of the nuisance.
Drs. Andrewes and Hurtley remark (p. 26 of their report) that
"the problem of sewer ventilation lies in the freest possible admixture
of the sewer air with the fresh air outside the sewer," and in this
opinion the Committee entirely concur. It has hence been adopted as
the principle which must underlie all practical measures in dealing with
the problem.
The report of the bacteriologist and chemist was referred to the
Borough Engineer, and the Committee have had the advantage of receiving
a report on the recommendations, and also other reports and
statements.
It will be noted that, in the opinion of the Borough Engineer and
all other observers, the gradient of the sewers is satisfactory, and the
flow of the sewage steady and at a good speed.
Of the 58 miles of Borough Council sewers, 34½ miles are brick of
varving size, and it is from ventilators in these brick sewers, or in pipe
sewers immediately in connection with them, that the smells arise. It is
improbable that brick sewers of this nature would be constructed at the
present time, and there can be no doubt that it is to their existence in