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INTRODUCTORY NOTES
COMPARING THE ANALYTICAL RESULTS OBTAINED DURING THIS
QUARTER WITH THOSE OF THE CORRESPONDING QUARTER OF 1909.
Trichinopoly.— Although there would appear to have been less rain during the
past three months than in the corresponding period of 1908–1909, the river on this
occasion is more flooded. This is explained by want of rain at the source of the
Cauvery in the earlier year. This time there are fewer excremental germs but a far
higher total count. In 1909, the water after passing the infiltration gallery was
uncommonly good, but it has not maintained the same high standard this year. On
both occasions there is a slight increase in hardness after passing the gallery which
would seem to point to some admixture with sub-soil water.
Tanjore.—Precisely the same conditions as regards local and distant rain and as
regards the river Coleroon are here seen as were noted under Trichinopoly. The
river, though flooded, does not contain the objectionable species noted last year, and
the infiltration gallery was working fairly well. A more frequent flushing of the
post-filtration passages might reduce the number of varieties to be found in the water
from the distributary system. Some sub-soil water is probably getting into the
supply, as the river water is not so hard or so saline as the water from the infiltration
gallery.
Cuddapah.—The meteorological conditions were fairly similar in the two years,
and so was the quality of the unfiltered water. In 1910, however, the filtered water
was much worse than in the previous year. Silt in the post-filtration passages and
in the pipes is probably the cause of this.
Adóni. —With apparently much the same meteorological conditions in force the
quality of the water is astonishingly different in the two years and very much worse
in 1910. Chemically the water is always so bad that water subject to such pollution
should be most carefully filtered and the pipes frequently flushed out.
Conjeeveram.— Owing to a change in the order of taking the samples, there is no
very closely corresponding date in the two years, The special feature for 1910 was
the marked improvement of the water of the infiltration gallery over that of the river
water. In 1909 the water of the river was just as good as the filtered water.
Madura.—The water was very much worse in this quarter than in the corre-
sponding quarter of 1909 ; but in both years we note the introduction of recent pollu-
- t i o n b y
p a s s a g e t h r o u g h
t h e g a l l e r y a n d p u m p s . S u r e l y t h i s s h o u l d b e p r e v e n t i b l e .
Dindigul.— The deep well was not in use in 1909, so no comparison can be made.
Q u a n t i t a t i v e l y ,
t h e i m p u r i t i e s i n
t h e w a t e r f r o m t h e i n f i l t r a t i o n g a l l e r y w e r e m u c h
better in 1909, but qualitatively they were worse. Considering that there was more
rain in the previous year, this is just the reverse of what might have been expected.
Madras.—The meteorological conditions varied greatly in the two years and so
did the analytical results. It is difficult, however, to make out any connection bet-
- w e e n t h e t w o s e t s o f c i r c u m s t a n c e s , a s t h e a n a l y t i c a l r e s u l t s v a r y m o s t c a p r i c i o u s l y .
Coonoor.— In all respects the water was better in 1910. The relation between
the water of the storage and service reservoirs as regards quality is as usual. Most
fortunately the astonishingly bad results got from le distributary system in 1909,
have not been maintained.
Ootacamund.— The only results which vary materially in the two years are those
obtained with the waters of the Tiger Hill and Kodappamund reservoirs. The
former is much worse in 1910, the latter in 1909. As already noted the variations
in these lake waters where the gathering grounds are presumably much alike as
regards nature and liability to pollution are not a little puzzling.
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