CHAP. VI. nrKF/S CANAL To lirNCOllX. 385 



lions with economy and despatch. Where there was a 

 break in the line of work, occasioned, for instance, by 

 tin- erection of some bridge not yet finished, the engi- 

 neer had similar barges constructed and carried by 

 land to other lengths of the canal which were in pro- 

 gress, where they were floated and advanced in like 

 manner for the use of the workmen. When the bridge 

 across the Mersey, which was pushed on with all despatch 

 with the object of economising labour and cost of mate- 

 rials, was completed, the stone, lime, and timber were 

 brought along the canal from the Duke's own property 

 at Worsley, as well as supplies of clay for the purpose 

 of puddling the bottom of the water-way ; and thus the 

 work rapidly advanced at all points. 



As one of the great objections made to the construction 

 of the canal had been the danger threatened to the sur- 

 rounding districts by the bursting of the embankments, 

 Brindley made it his object to provide against the occur- 

 rence of such an accident by an ingenious expedient. 

 He had stops or floodgates contrived and laid in various 

 parts of the bed of the canal, across its bottom, so that, 

 in the event of a breach occurring in the bank and a 

 rush of waters taking place, the .current which must 

 necessarily set in to that point should have the effect of 

 immediately raising the valvular floodgates, and so shut- 

 ting off the stream and preventing the escape of more 

 water than was contained in the division between the 

 two nearest gates on either side of the breach. At the 

 sin ne time, these floodgates might be used for cutting 

 off the waters of the canal at Different points, for the 

 purpose of making any necessary repairs in particular 

 lengths ; the contrivance of waste tubes and plugs being 

 so arranged that the bed of any part of the canal, more 

 especially where it passed over the bridges, might be laid 

 bare in a few hours, and the repairs executed at once. 

 In devising these ingenious expedients, it ought to be 

 remembered that Brindley had no previous experience 



VOL. i. 2 c 



