'The Transactions of the Bombay Geographical Society. From January 1863 to December 1864. (Edited by the Secretary.) Volume XVII.' [‎15] (176/524)

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BOMBAY TIDAL OBSERVATIONS FOR 1861.
but it tends to lessen our confidence in those of other years ; and from a
cursory examination of those for 1858, I am inclined to suspect they
are equally valueless. How they should he so it is not for me to de
termine—if it is to be attributed in part to the instrument, it is cer
tainly a great pity that the observations were not stopped at once
when it first failed to give correct indications ; or they might have
been made independently of the guage until it had been again restored
to working order.
Postscript.
It was only yesterday morning I had the opportunity of perusing
the report of Lieutenant Fergusson’s remarks at the last meeting. These
I think require further notice. Lieutenant Fergusson seems to place
very little value on the correct registration of the tides, and attributes
a surprisingly large effect to the wind on the times of high-water. In
this latitude, where the winds vary their direction with the seasons, we
may expect that formulae founded on the observations will embrace
their mean effect. But independently of this, it is remarkable if the
effects are so great as those attributed. Sir John W. Lubbock, in
order to ascertain the effects of the different winds in accelerating or
retarding the time of high-water says, he “ calculated all the times
of high-water for the year 1826/ 5 and requested Mr. Dessiou to
classify the tides observed in that year according to the different winds
noted against every observation in the register” kept at the London
Docks. The greatest retardation was found to occur when the direc
tion of the wind was ESE., and the mean of the times of 14 observed
tides was found to differ only 7 minutes from the computed times.
The greatest average acceleration was found to be 12 minutes on an
average of 37 observed tides when the direction of the wind was NW.
Again in a later paper, exhibiting the final results of his discussion
of the London Dock observations from 1808 to 1826 inclusive, he
states the mean effect on an average of 16 observations, when the
direction of the wind wasEbE- to be a retardation of only 5 minutes and
a depression of 3 inches on the height; the average acceleration when
the direction of the wind is SSW. he gives as 4 minutes. These are
the largest mean differences given between observation and calculatiom
Observations at other ports also tend to show that the effect of the
wind is not generally very great. The Committee of the British
Association, in their Seventh Report on Waves, say—“ The magnitude of