350 THE BRJDGEWATEB CANAL PACT V. 



natural level. Accordingly, Brindley contrived a weir, 

 over which the stream fell into a large basin, from 

 whence it flowed into a smaller one open at the bottom. 

 From this point a culvert, constructed under the bed of 

 the canal, carried the waters across to a well situated 011 its 

 further side, where the waters, rising up to their natural 

 level, again flowed away in their proper channel. A 

 similar expedient was adopted at the Manchester terminus 

 of the canal, at the point at which it joined the waters 

 of the Medlock. It was a principle of Brmdley's never 

 to permit the waters of any river or brook to intermix 

 with those of the canal except for the purpose of supply ; 

 as it was clear that in a time of flood such intermingling 

 would be a source of great danger to the navigation. In 

 order, therefore, to provide for the free passage of the 

 Medlock without causing a rush into the canal, a weir 

 was contrived, 366 yards in circumference, over which 

 its waters flowed into a lower level, and from thence into 

 a well several yards in depth, down which the whole 

 river fell. It was received at the bottom in a subter- 

 ranean passage, by which it passed into the river Irwell, 

 near at hand. The weir was very ingeniously contrived, 

 though it was afterwards found necessary to make con- 

 siderable alterations and improvements in it, as experi- 

 ence suggested, in order effectually to accommodate the 

 flood-waters of the Medlock. Arthur Young, when 

 visiting the canal, shortly after it was opened up to 

 Manchester, says, " The whole plan of these works shows 

 a capacity and extent of mind which foresees difficulties, 

 arid invents remedies in anticipation of possible evils. 

 The connection and dependence of the parts upon each 

 other are happily imagined; and all are exerted in 

 concert, to command by every means the wished-for 



success." l 



Brindley 's labours, however, were riot confined to the 



1 ' Six Months' Tour through the North of England,' vol. iii., p. -f>s. 

 Ed. 1770. 



