fttt 



tide to rise to the mean height of the two extremes, it 

 would give only eighteen inches, or two feet, 



Admitting it to be nearly the same at the mouth of 

 the Indus, we cannot suppose that the tide had any in- 

 fluence in checking the current of that river, indeed, 

 if Mr. RennelVs account be true, the tide, at present, 

 does not extend up so high as the head of the delta, or 

 the ancient mouth of the river, by fifty miles : for the 

 delta being one hundred and fifteen miles from its head 

 to its extremity, and the tide being perceptible only 

 sixty-five miles from, or above its mouth, leaves a dif- 

 ference of fifty miles. 



If, in this instance, Mr. Rennell meant that the 

 tide was only perceptible, at the distance of sixty-five 

 miles above the original or ancient mouth of the Indus, 

 it would make some difference. But this, 1 have rea- 

 son to believe, he did not, from what he says of the 

 Ganges. 



" In the Ganges the tides are perceptible at two hun- 

 dred and forty miles up ."* 



Now the head of the delta of the Ganges being two 

 hundred and twenty miles from the sea,f gives an ex- 

 cess of the tides above the head of the delta, or- 

 ancient mouth of the river, equal to twenty miles, 

 which is highly probable, from the known height to 

 Which the tide rises in those seas. This being the 

 case, it must appear evident, that the tides had but lit- 

 tie or no influence, in checking the currents of those 



* Kennell's Map of Hindostan, page xxiv. f Do, page 358, 



