348 



THE ELLESMEEE CANAL 



TART VIII. 



was 47,0 18., which was considered by Telford a mode- 

 rate sum compared with what it must have cost if 



VIEW OF POST-CYSYLLTAU AQUEDUCT. 

 QBy Percival Skelton, after his original Drawing ] 



moir of William Jessop,' published in 

 4 Weale's Quarterly Papers on Engi- 

 neering,' points out the bold and ori- 

 ginal idea here adopted, of constructing 

 a water-tight trough of cast iron, in 

 which the water of the canal was to 

 be carried over the valleys, instead of 

 an immense puddled trough, in ac- 

 cordance, with the practice until that 

 time in use ; and he adds, " the im- 

 mense importance of this improve- 

 ment on the old practice is apt to be 



lost sight of at the present day by 

 those who overlook the enormous size 

 and strength of masonry which would 

 have been required to support a pud- 

 dled channel at the height of 120 

 feet." Mr. Hughes, however, claims 

 for Mr. Jessop the merit of having 

 suggested the employment of iron, 

 though, in our opinion, without suffi- 

 cient reason. Mr. Jessop was, no 

 doubt, consulted by Mr. Telford on 

 the subject ; but the whole details of 



the 



