188 
Analyses of Books. [June, 
The changes of the course of the great river, since Colebrooke s Maps of 1796, 
have been ascertained within tolerable limits, by the recohnoitering voyage of the 
Hooghly : those of the Jellingbee and Bliagurutee have been accurately laid down 
in Captain Prinsep’s River Charts, from Mr. May’s recent surveys. 
Above Buxar, the high-water channel does not appear to have undergone much 
alteration, but below that spot the character of the river changes, and its banks 
are composed of a softer alluvium : the following are a few of the principal aber- 
rations within the last 30 years. 
The mouth of the Surjoo, formerly 2 miles below Bullea, is now 1 mile above it, 
and the latter place is upon the edge of the bank. From hence the old and the 
new course cross one another like the interwoven coils of a double corkscrew ; 
abandoning the banks of Chupra, encroaching upon Dinapoor, depositing a 
wide strip of culturable land in front of Bankipoor, and cutting away a breadth of 
2 miles at Futwa. 
There are certain points of intersection which remain, in a measure untouched 
in this oscillation of the stream, and experience seems to have pointed these out as 
the sites adapted for building; such are Patna, Bar, Soorujgutta, Baghulpoor: 
some are fixed by natural or artificial obstacles, as the rocky points of Colgong 
and Puthurghata, and the brick bastions of Monghir and Rajmahal. 
Below Monghir the new channel deviates 4 miles to the northward, leaving a 
large tract of chur-l and near Seetacoond, The island in front of Baghulpoor, has 
been more than half eaten away, bringing the stream to its ancient course near 
that town : “ should it direct its force once more round the high bank thence to 
Souludgunj, we may again behold the formidable Colgong rocks, as in Rennell’s 
time, and in Colebrooke’s remembrance, surrounded by dry land.” 
At the present moment the famed pass of Peerpointee is deserted by the main 
river, which holds its course in the very centre of Colebrooke’s island of D (Ta 
Khoaspoor, and a comparatively tranquil stream washes this place, dreaded by 
trackers, the passage to which is closed entirely during the dry months. Th e 
river, as if to compensate for deserting such a spot, is however apparently break- 
ing its way afresh into the Terryagullee bend, under the foot of the beautiful 
hills which uprear their gi-een masses to relieve the otherwise dull monotony of 
sand and water. 
At Rajmahal, the last permanent rallying point is passed, and the river appe ars 
only to cease its corrosions of any bend of soft alluvium, and betake itself to an 
opposite channel, “ when it has overshot the cuiwature proportioned to its magni- 
tude.” 
The last sentence, (from the River Memoir,) alludes to a principle pointed out by 
Captain Prinsep, that in running water the magnitude of every elbow, or curve at a 
change of direction, is in direct proportion to the momentum, (or body and velocity,) 
of the stream. Thus it may be generally remarked, that the radius of curvature for 
the windings of the Ganges, when full, is about 2§ or 3 miles ; and if a mean line be 
drawn in the direction of its course, its meanderings may be rudely represented 
by semicircles of 3 miles radius on either side thereof; the whole breadth of coun- 
try, therefore, liable to alternate corrosion and deposit, will be about 6 miles. The 
bends of the Jellinghee and Bhageeruttee have a curvature of fths mile radius; 
those of the Matabhanga are of less than i th mile ; while after their union in the 
Hooghly, the radius increases gradually to nearly 1£ mile at Calcutta. 
In the map of the Bhageeruttee may be traced a further exemplification of this 
principle in the gradual extension of the circle, until at last the narrow neck is cut 
through, and the river instantly deserts the long course round the bow, for the 
