.314 LIEUT.-COLONEL SYKES’S DISCUSSION OF METEOROLOGICAL 
Observations on Horary Oscillations. 
It is hence seen that in the month of March the diurnal tide, which usually falls 
from 10 A.M. until 4 p.m., turned at 3 p.m., and should then have gradually risen until 
9 — 10 P.M., instead of which it rose only until 4 p.m. and then fell until 5 p.m., when 
it turned again and ran its usual course. In the same month the a.m. tide, which 
usually falls from 10 p.m. until 4 a.m., had its fall interrupted at 2 a.m. and rose until 
3 A.M., when it turned and fell to its ordinary minimum, and then gradually rose 
until 10 A.M, In the month of May the daily minimum occurred at the proper hour, 
4 P.M,, and its ordinary regular rise continued until 5 p.m. ; but at this hour it changed 
and fell until 6 p.m., but at that hour resumed its usual course. The other tides were 
free from these aberrations, but two of them turned at 3 and 9 a.m. instead of 4 and 
10 A.M. In the month of June the flow is irregular in the 4 a.m. tide. Its minimum 
occurs properly at 4 a.m,, and it rises until 5 a.m., but at this hour it has turned, 
instead of continuing to rise, and falls until 6 a.m., when the barometer is as low as at 
4 A.M., — a solitary instance within the year. In the month of January 1848, the falling 
tide from 10 p.m. goes on regularly until midnight, when it turns and rises until 
1 A.M. ; it then turns again in the proper direction, but instead of stopping at 4 a.m., 
the minimum hour, it continues until 5 a.m. and then turns. An inspection of the 
Table shows that the barometer never appeared to remain stationary at the turning 
hour of the maximum a.m. (9 — 10) tide, but that in the months of January, February 
and April, no movement of the tide took place for a full hour at the 9 — 10 p.m. maxi- 
mum tide. In August, although the other tides flowed as usual, that of the a.m. 
period remained stationary from 2 — 4 a.m., both inclusive. The maximum a.m. tide 
occurred six times in six months of the year at 9 a.m., and six times in the other six 
months at 10 a.m. The maximum nocturnal tide took place only twice at 11 p.m., 
thrice at 9 p.m., five times at 10 p.m., and thrice was stationary between 9 and 10 p.m. 
The minimum diurnal tide turned once only at 6 p.m. The chief irregularities appear 
to have been in the a.m. minimum nocturnal tide, embracing the hours from 1 — 6 a.m. 
On looking over the Madras hourly observations for four years for the twenty-four 
hours between the 21st and 22nd of each month in the year 1842, there are only two 
instances of similar irregularities. On the 22nd of March in the falling a.m. tide at 
2 h 4 im ^ jyj ^ barometer stood at 29 859, and at 3^ 41“ a.m., instead of continuing 
to fall, it had risen to 29‘869, but at 4*^ 41“ it resumed its regular course and fell to 
29'865. On the 22nd of November an irregularity occurred in the nocturnal p.m. 
tide. At lO'* 41“ the barometer stood at 30'004 ; at 11*^41“ it had fallen in due 
course to 29’991, but at 12*’ 41“ it had risen to 29*992, and only at 1^ 41“ resumed 
its usual ebb, and fell to 29*981. In the year 1843 there are also only two instances 
of irregularity in the specified days ; namely, on the 2 1st of August in the a.m. falling 
tide. At I** 4l“A.M. the barometer stood at 29*722; at 2’’ 41“, instead of falling, it 
rose to 29*725, then fell, at 3*' 41“, to 29*724 ; then rose, at 4^^ 41“, to 29*726, and con- 
tinued regular to the maximum period at 9 a.m. On the 21st of December, at ll^^ 41“ 
