OBSERVATIONS TAKEN IN INDIA. 
317 
exceptions to the former and only one to the latter ; but two of the exceptions are 
remarkable, the tide having turned on the 7th and 28th of January 1848, at 2 p.m. 
I do not recollect a single case of the kind in the records in India. In the first of 
these cases the tide flowed from 2 until 9 p.m., seven hours ; and in the second it re- 
mained stationary from 2 until 3 p.m., and then flowed until 10 p.m. ; this portion of 
the diurnal movement of the atmosphere occupying eight hours instead of six. As a 
contrast to these lengthened periods, we find that the 3 p.m. ascending tide, on the 
25th of January and 20th of June 1847, flowed only from 3 p.m. until 8 p.m., five 
hours instead of eight. On the 15th of January 1848, the ascending a.m. tide did 
not attain its maximum until 11 a.m., but this retardation was probably owing to an 
inversion in the flow at 7 a.m. ; the pressure, instead of increasing at this hour, having 
diminished from 29*572 at 6 a.m. to 29*563, but after this interruption the usual in- 
crease took place up to 1 1 a.m. It will be seen that there are two instances of a station- 
ary state of the barometer on the 28th of January 1848, from 2 to 3 p.m., and on the 
21st of June 1848, from 3 to 4 p.m. Meteorologists know that this circumstance, 
which would excite no attention without the tropics, is of rare occurrence within the 
tropics. The next great feature in this Table is the absence of any retrograde move- 
ment in the p.m. descending and ascending tides ; but this is not the case with the other 
two tides ; as at Dodabetta, several interruptions in the flow or ebb are recorded. In 
the descending nocturnal a.m. tide there are three instances. On the 15th of January 
1847, at 1 A.M., the tide has risen from midnight instead of continuing to fall. Pre- 
cisely the same thing occurs on the 7th of January 1848, at the same hours. On the 
21st of June the interruption occurs at an earlier hour. The pressure is at its maxi- 
mum at 9 P.M. ; it then diminishes until 10 p.m., but instead of continuing to diminish 
it increases until 11 p.m., but at midnight has resumed its usual course. In the a.m. 
ascending tide there is only one instance of inversion ; on the 15th of June 1848, the 
usual rise stops at 6 a.m. and retrogrades until 7 a.m., it then resumes its usual flow 
and continues until 11 a.m., a very unusual hour for the period of the maximum of 
the A.M. tide. Had the term-days of the other months been noticed, numerous in- 
stances of deviations from normal conditions could have been given. It v)ould he de- 
sirable to ascertain whether these aberrations have any relation with changes in the 
electrical tension in the atmosphere. 
If these anomalies be tested by a comparison with hourly readings of the barometer, 
at Aden corrected for the tension of vapour*, for four days in each month of the 
year 1847, not only is their occurrence rendered unquestionable, but new phases in 
abnormal conditions appear. Annexed is a Table of the “ Means” of hourly readings 
of the barometer in four days in each month at Aden in 1847, corrected for 
MOISTURE. 
* Corrected by the observer. 
