1831 .] 
Analyses of Books. 
185 
XI . — Analyses of Books. 
An Account of Steam Vessels , and of Proceedings connected with Steam Naviga-> 
tion in British India. By G. A. Prinsep, Esq. Calcutta Government Press, 1830. 
[Concluded from our last.] 
In our last number was given a brief abstract of Mr. G. A. Prinsep’s recent pub- 
lication on Indian Steam Navigation, with reservation for the present occasion, of 
his observations on the peculiarities of the Ganges as a navigable river. 
Where a writer is not himself prolix or redundant, and where his remarks are 
all to the point, the difficulty of condensing them is much increased ; and we know 
not how to choose a middle course between embodying the whole of his chapter, 
and contenting ourselves with a mere index of his deductions. 
The characteristic features of the Ganges are fully described in Rennell’s Me- 
moir; but that great geographer seems to have been much misled as to some of 
the elements of its navigability ; such as average depth , slope of surface, and 
discharge. 
Thus he asserts, that “ at 500 miles from the sea, the channel is 30 feet deep, 
when the river is at its lowest, and continues at least of the same depth to the sea ; 
while no spot below Allahabad is known to be at any time fordable to an ele- 
phant.” Again, he concludes from an instrumental level of 60 miles, made by order 
of Mr. Hastings, that the average slope of surface is 9 inches per mile : but the most 
serious error of all is in his supposition, that the quantity of water discharged by 
the Ganges, in the freshes, is only 4§ times greater than during the dry weather; and 
that the melting of snows, or showers among the mountains, contribute so much as 
one-half to the annual rise 1 . 
The real circumstances of the mighty Ganga are widely different. It is strictly 
a tropical river, subject to alternate freshes and droughts ; and with exception, per- 
haps, of the Delta itself, the country through which it flows is remarkable for the 
perfect contrast of its wet and dry seasons : from October to June, it may be said 
that not a drop of rain is seen ; while during the remaining three months, it falls with 
hut little intermission : the consequence is, that great inequality prevails in the 
hulk of the stream, and that the maximum and minimum discharge are more nearly 
as 100 to 1 than in the proportion quoted from Rennell. The following table 
shews the data from which this estimate, rude as it is, has been worked out : 
River. Season. 
Ganges at Benares, April, 
Rains, 
Do. at Sikrigall, April, 
Rains, 
Breadth of 
Average 
Average 
Discharge 
surface. 
depth. 
velocity. 
per second. 
1400 ft. 
34,75 ft. 
1410 ft. 
20000 ct 
3000 
58,0 
26400 
1372500 
5000 . 
3,0 
5000 
21500 
10000 
28,0 
26400 
1850000 
For the sake of comparison, the circumstances of the great American river, are 
subjoined, as extracted from from Captain Hall’s work. 
Mississipi at ) Lowest ebb, 2400 50,0 3000 100000 
Natchez, j Maximum, 2700 100,0 13200 1000000 
The average discharge of the Ganges throughout the year, may hence be calculated 
as 250000 cubic feet per second, at Benares, and 500000 at Sikrigall : which is 
J Another error, committed by Major Rennell, not noticed by our Author, but one 
which has done serious harm at home, in leading to false deductions, is probably duo 
to a mistake of the printer: he asserts, that the water of the freshes holds in suspension 
4U1 of its weight of silt or sand : now this must evidently mean either ^th per cent, or 
45th that is per cent, and the latter is the utmost that can be allowed. 
