28 
THE REV. W. WHEWELL ON THE TIDES OF THE PACIFIC, 
diurnal inequality, apparently amounting to one or two hours, in the time of high 
water, but no conspicuous diurnal inequality in the heights. The inequality or irre- 
gularity of the times is so great, that it is difficult, at this place, to speak of a tide- 
hour. The lunitidal interval varies from 11|^ hours to 16| hours. 
50. I shall not entangle myself in the seas broken by innumerable large and small 
islands which extend from Torres Straits to the coasts of India, Arabia, and Africa ; 
but I may observe that in these Indian seas the diurnal inequality is very marked 
in general, as I have already noticed for several places. I will refer back to these. 
Phil. Trans. 1839, Part I. p. 164. Bassadore, at the entrance of the Persian Gulf. — 
A very large inequality of the times, amounting in some instances to more than two 
hours. 
Surat and Gogah, in the Gulf of Cambay. — A large diurnal inequality in the heights 
of high water, amounting to not less than seven or eight feet. The age is two days. 
Phil. Trans. 1833, p. 221. The River Hoogly. — The night tides highest from No- 
vember to February : the day tides highest from March to October. 
Phil. Trans. 1833, p. 224. Tonquin. — One tide in twenty-four hours. 
Phil. Trans. 1837, Part I. p. 78. Sincapore. — A very large diurnal inequality, 
high water heights, diurnal inequality — If ft. Low water heights, diurnal inequa- 
lity = 6 ft. 
The age of the diurnal inequality is a day and a quarter. 
This very large diurnal inequality in the low water heights of Sincapore was, so 
far as I know, a new fact, when it was thus extracted from the observations, and was 
probably looked upon by most persons as a singular case. There is however good 
reason to believe that the same fact extends over the whole of the sea in that region. 
At least I have the means of showing that it prevails on the north coast of Australia, 
namely, at Port Essington. 
51. Port Essington. — I am supplied with a considerable series of observations, 
somewhat interrupted, made by Sir Gordon Bremer, of which I have thrown five 
semilunations into curves. The observations indicate a diurnal inequality in the 
high water heights, but not very regularly. But at low water there is a diurnal in- 
equality, of which the magnitude is not less than four feet, and this appears to be 
regular. The observations however are not exact enough to determine the age of 
this diurnal inequality. 
I will add, as apparently connected with this, a reference to the peculiarities of the 
tides in the Gulf of Carpentaria. Flinders found only one ebb and one flood in the 
day, as I have noticed*. 
I may remark, that the phenomena involved in the diurnal inequality are very 
curiously distributed to some of our principal colonies in Australia. At Adelaide, 
on the south, there is a large diurnal inequality in the heights of high water: at Port 
Essington, on the north, this inequality falls mainly upon the low water ; while at 
* Philosophical Transactions, 1833, p. 225. 
