'The Transactions of the Bombay Geographical Society. From January 1865 to December 1867. (Edited by the Honorary Secretary.) Volume XVIII.' [‎73] (100/268)

BOMBAY GEOGRAPHICAL SOCIETY.
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and in the neighbourhood of tidal creeks as far within the Rann as practicable;
and an accurate determination of the height of a point upon each above mean
tide-level. A very few of these would suffice if placed at well-selected points.
I believe there is a party of the Topographical Survey at present engaged in
Kattyawar who could without loss of time see that this was done. And the
bench marks left by the Officers of the Great Trigonometrical Survey, while
running their levels from Kurrachee, will always prove carefully determined
and excellent points for comparison, wherever available.
But these evidences of a change in relative level of land and sea, derived
from facts observed in the Eunn of Cutch, are only a very small portion of similar
facts which have been noticed elsewhere round the coasts of India. These occur
almost every where, and along the entire coast, and for the most part they point
to a rise in the land. This universality of the facts, however, reduces the ques
tions now stated with reference to the Eunn to form a very minor part of a very
large and highly important inquiry. For the settlement of this, the establish
ment of a chain of points and fixed marks round the coasts of India, and the
accurate determination of their height above mean sea level, would be neces
sary, and would be of the highest value to science. All buildings with good
solid foundations which lie close to the sea shore would furnish means of fixing
such marks. The several forts which protect the harbours round the coast, all
the light-houses, harbour piers, &c., all these would afford capital points for the
fixing of such marks.
I have spoken of the necessity of an accurate determination of the level of these
points. It is an easy matter to determine with accuracy the difference of level
of two fixed points, not far distant from each other. But in the present case it
is necessary in the first place to fix one of those points before the relative level
of the other can be ascertained. The exact line of mean sea-level must be
determined. This can only be done by a series of observations steadily and
systematically pursued daily for more than a month at intervals, or for a year if
practicable. There is no real difficulty in the case ; it only requires ordinary
caie, but this care continued for such a time as to eliminate the disturbing effects
of local or temporary causes. Once determined, these observations need not be
repeated again for several years, say ten, when the exact relative level of the
fixed mark, as compared with the mean tide level, should be again determined.
It will be sufficient to prove the necessity for great care and accuracy to state
that in every case in which such a secular change of level has been established,
the change has not amounted to more than a few inches, or a foot or two, in a
hundred years.
I would urge upon the Government of Bombay From c. 1668-1858, the East India Company’s administration in the city of Bombay [Mumbai] and western India. From 1858-1947, a subdivision of the British Raj. It was responsible for British relations with the Gulf and Red Sea regions. the establishment of such
uiaiks and the conduct o± such careful observations at favourable points along
Ike coast. A very long line of coast well exposed, with points admirably adapted
foi such observations, and the advantage of a noble harb our, ought to induce it
to take the lead in such researches in India.
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