158 RENNIE'S DRAINAGE OF TART VII. 



surplus water anyhow, either by turning it into the 

 nearest river, or sending it in upon a neighbour. What 

 was done in one season was very often undone, or 

 undid itself, in the next. The ordinary drainer did not 

 care to look beyond the land immediately under his own 

 eyes. Mr. Rennie's practice, on the contrary, was founded 

 on a large and comprehensive view of the whole sub- 

 ject. He was not bounded by the range of his phy- 

 sical vision, but took into account the whole contour of 

 the country ; the rainfall of the districts through which 

 his drains were to run, as well as of the central 

 counties of England, whose waters flowed down upon 

 the Fens ; the requirements of the lands themselves as 

 regarded irrigation and navigation ; and the most effec- 

 tual method not only of removing the waters from 

 particular parts, but of providing for their effectual 

 discharge by proper outfalls into the sea. 



What was the problem now to be solved by our 

 engineer ? It was how best to carry out to sea the 

 surplus waters of a district extending from the eastern 

 coast to almost the centre of England. Various streams 

 descending from the Lincolnshire wolds flowed through 

 the level, whilst the Witham brought down the rainfall 

 not only of the districts to the north and east of Lin- 

 coln, but of a large part of the central counties of 

 Rutland and Leicester. It was therefore necessary to 

 provide for the clear passage of these waters, and also to 

 get rid of the drainage of the Fens themselves, a con- 

 siderable extent of which lay beneath the level of the 

 sea at high water. It early occurred to Mr. Rennie 

 that, as the waters of the interior for the most part came 

 from a higher level, their discharge might be provided 

 for by means of distinct drains, and prevented from at 

 all mingling with those of the lower lying lands. But 

 would it be possible to " catch " these high land waters 

 before their descent upon the Fens, and then to carry 

 them out to sea by means of independent channels ? 



