480 FOURTH REPORT — 1834. 



direction of Messrs. Telford and Rennie, and the result has ex- 

 ceeded the most sanguine expectations. 



The lands hmnediately drained by this Cut were estimated to 

 amount to .35,000 acres. 



The improvements of the river were estimated at j£373,7l3. 



And the internal drainage at 263,604. 



Making a total of . . 637,317 



According to Mr. Wing, the district drainage which would be 

 effected by the river Nene would amount to 116,900 acres. 



" The effect which the works, when completed, will have on ' 

 the internal drainage of the fens connected with them may be 

 appreciated," says Mr. Wing, " by the following facts : The 

 windmills used in the North Level are not permitted to throw 

 any water to the height of more than four feet above the lands 

 in Thorney North Fen, which ai-e about four feet three inches 

 above the cill of Gunthorpe Sluice, making the greatest fall 

 which can be obtained from the drains only eight feet three 

 inches ; but it seldom happens that the low-water mark is less 

 than two feet above the cill, so that the general fall may be 

 considered as not more than six feet three inches ; whereas the 

 low water at Crab Hole is nine feet nine inches below the cill of 

 Gunthorpe Sluice, and consequently below the lands in Thorney 

 Fen." Another important object was that at least 10,000 acres 

 would be gained from the sea by the improvements, and this 

 operation is now going on very rapidly. The expense of up- 

 wards of sixty vrindmills, costing on the average 4385/. per 

 annum, would be saved, independently of other advantages, all 

 of which are fully detailed in Mr. Wing's pamphlet *. 



A similar plan for a Cut has since been carried into execution 

 on a modified scale below Boston, in Lincolnshire, and with cor- 

 responding benefit both to the navigation and drainage. 



Principles similar to the foregoing have been recommended by 

 Mr. Rennie in his various Reports on the drainage of the marshes 

 of Hatfield Chase, Congresbury, Romney, Holderness, &c. 



The system of canal navigation in England has been carried 

 on for more than half a century on a scale no less extensive 

 than the drainage. The completion of the Sankey Canal in the 

 year 1760, and of the Bridgewater Canal in the year 1761, 

 opened the eyes of the nation to the vast advantages that were 

 likely to be derived from artificial navigation, and led to the 



* Considerations on the Principles of Mr. Rennie' s plan for the Drainage of 

 the North Level of South Holland. By Tyclio Wing, Esq. Peterborowgh, 1820, 



