12

REPORT ON THE WORKING OF THE KING INSTITUTE, GUINDY

be incurred in the purchase of stores and apparatus for the use of the
Public Analyst.

   The number of samples of water examined during the year was 1,221
(statement No. 14), an increase of 10 per cent over last year's figure. The
half-yearly routine examination of protected municipal, jail and railway
station supplies yielded 665 samples, an increase of 50 per cent over the
previous year. The experimental filters at Guindy accounted for 392
samples, an increase of about 35 per cent. One hundred and sixty-four
samples were examined for the Madras Corporation. There was a
decrease of about 200 samples under this heading, as a result of the
Corporation now getting their analytical work done by their Analyst who
was trained at the King Institute. In spite of this decline, the total
number of samples examined shows an increase, and the institute is now
free to devote greater time and attention to research work and to mufassal
water-supplies.

   The following is a review of the various protected water-supplies in
the Presidency:—For details, see Appendix I.

   Municipalities.—Of the ten sand filter installations, Berhampur and
Ellore yielded good results, which were due in a large measure to the
adoption of the newer method of filming slow sand filters with alum, on
the strength of the success which attended the experiments carried out at
Guindy under the direction of the Committee on Water Filtration. The
Water-supply to Adōni Municipality has continued to be in a most
unsatisfactory condition for several years and no attempts have yet
been made to set matters right. The slow sand filters at Salem have
been working very unsatisfactorily and producing a large amount of
sulphuretted hydrogen, with the result that the town has been receiving
a supply inferior in quality to the raw water of the tank, which is always
liable to gross excremental pollution. The slow sand filter installation
at Periyakulam has not been acting beneficially and will require a
thorough overhaul.

   The Vizagapatam Municipality has had its sand filters overhauled
and relaid, resulting in the yield of a filtrate of good quality. An initially
fair filtered supply was found to deteriorate in transit through a dirty
reservoir and a fouled pipe line at Kurnool; this is easily remediable at
no great expense by periodical, systematic and thorough scourings.
Vellore and Cocanada afford examples of water-supplies of a variable and
indifferent quality. It is not necessary to say anything here about the
condition of the Madras City water-supply beyond inviting attention to
the two reports of the Committee on Water Filtration, submitted to
Government during the year.

   Of the three mechanical rapid sand filter installations in the Presi-
dency, that at Masulipatam is the only one which has functioned
effectively. The Chidambaram filter has never been worked satisfactorily
and formed the subject of a special communication to Government during
the year. At Erode the mechanical filter plant has never been anything
but a mere strainer. The success of mechanical filtration depends mainly
on the proper coagulation of the raw water with the optimum dose of
alum and where this factor is neglected, the entire process of purification
is vitiated.

   With the opening of the Anantapur water-works early in the year,
the number of infiltration gallery supplies in the Presidency rose to fifteen.
Of these, Anantapur, Nellore, Tirupathi and Rāmēswaram were in good
order throughout the year under report. At Tanjore and Gudiyāttam an
initially good supply was found to reach the consumer in an unsatisfac-
tory condition as a result of storage in a dirty reservoir and passage
through a fouled pipe line. The necessity for a thorough cleaning at
regular intervals was pointed out to the authorities concerned. The