524 Wood's Report on the River Indus, [No. 115. 



IV. — Of the mode of Navigating the Indus. 



The diagram on the preceding page, represents a reach of the river 

 below Sehewan. The better to illustrate the figure, I shall suppose a 

 boat deeply laden at the village Y is about to start on the downward 

 voyage, and that her ''meerbaVj' or man in charge of the boat, is 

 a stranger to the river. Leaving the village, he would doubtless take 

 the large channel indicated by the colored arrows, without regarding, 

 if indeed they had been seen, the numerous offsets on the right hand ; 

 when abreast of the shoal S, a decrease in the depth of water would 

 for the first time apprise him of his having lost the fair channel, 

 and shortly after this intimation had been received, the boat would 

 ground on the bar G. Now by inspecting the sketch, it will be seen that 

 between the villages X and Y, the deep channel has shifted from the 

 left to the right bank of the river. The alteration has been effected by 

 the silent drainage of the lateral channels O, P, E, and D, and 

 by the unperceived departure of a large body of water over the bar 

 extending from S to G into the back water F. E is the passage the 

 boat should have pursued ; but this knowledge could only have been 

 the result of a previous careful examination, appearances at starting 

 being decidedly in favour of channel D. The nature of these changes 

 will be rendered still more evident, by inspecting a section of the 

 river's bed. Take for example the following : — 



1st. Channel. 2nd. Channel. 



S4 4i 4i .^1 91 O 3331333 1 11 li li O 91 Oi 23 1111 3^3313313 



3rd. Channel. 



1^.14.14.2.2.1.^ fathoms. Such a line of soundings is not uncommon, 

 though this one differs from the usual section in having an additional 

 channel, two being the more usual number. The junction of these is 

 not effected at a particular spot, but is, on the contrary, the result 

 of a parallel course of many miles, during the whole of which distance 

 the change is gradually being effected. They thus imperceptibly 

 glide into each other; and should the channel selected by a boat 

 descending the river, be that which the stream is in the act of 

 abandoning, she must be moved into the new formed channel as soon 

 as a decrease of soundings gives warning of the fact. Now it is deserv- 

 ing of remark, that when the necessity of change first becomes apparent. 



