( io ) 



XIV. Thus here was a weir with narrow under-sluices 

 Weirs with narrow under- at which the shad were being detained 



slakes, continued. endeavouring to ascend to their spawn- 



ing beds, although these under-sluices were open during 

 freshes, and the floods were so great that a mere ripple on the 

 surface of the river only marked the presence of a weir. In 

 spite of all this, no fish have been found to pass this obstruc- 

 tion, and surely did they do so, a solitary straggler might have 

 been taken. Even a barren fish, in fact, a shad of any sort, 

 had not appeared at Trichinoooly during the whole period 

 that this construction has existed and been intact. Shad, 

 or rather large fish, have been taken in these under-sluices, 

 but only when they were closed at the up-stream end. It 

 is true that a good current is then coming down between 

 the boards which close these vents or narrow passages, but 

 it does not prevent strong healthy fish from ascending as far 

 as the boards, but these very boards form an effectual bar 

 to their onward progress. The very use of the sluices is 

 to force the water down with such impetuosity that, during 

 high freshes when they are open, no Indian fresh-water fish 

 could possibly ascend when the weirs are several feet in 

 height : the water shoots down the openings and across 

 the apron, bubbling and boiling a hundred yards or more 

 down-stream. This torrent of about six feet in width is 

 like a mill race, or as if it were shot out of an engine, 

 carrying down stones, sand, &c, in its course, and which of 

 themselves would be sufficient to injure fish attempting to 

 ascend. From personal observation I am satisfied no fish 

 could pass up them : persous locally employed on these weirs 

 assert the passage of fish to be impossible : above such con- 

 structions these migratory species attempting to ascend cannot 

 be found; it must, therefore, be evident to any one who will 

 consider the question, that weirs are effectual barriers to the 

 ascent of fish, even although such possess narrow under-sluices 

 that are left open during the periods of the freshes. 



XV. The wide under-sluices, such as exist in the weirs 



weirs having wide under- at Cuttack and Midnapur, are con- 

 siuices no impediment to ascend- structcd on an entirely different prin- 



ing fish when such are open. ciple ^ pattcrn? foxing free gapS 



of many yards in width, so that, when open, fish cannot have 

 any difficulty in ascending through them. 



XVI. These weirs likewise, it is stated, may be topped 

 Fish unable to ascend over by fish during heavy floods, as then 



wens. they may ascend over them, especially 



when the summit of their wall is several feet below the 



