[ 221 ] 



the more, on to the trough : The boat is 

 then drawn over the fpot which is to be 

 filled up, and the earth there dropped : It 

 is aftoniming what a vaft laving is made by 

 this invention : In common management to 

 conduct a canal level acrofs a valley, and 

 without locks, would confume the revenue 

 of a whole county ; but fuch inventions as 

 thele eafe the expence at lead 5000 /. per 

 cent. The following fketch, Plate X. 

 Fig. 1. will give a clearer idea of theie 

 boat- waggons. 



A. The boat that appears on a fide view. 



B. The trough, fupported by the piece? 



c, c, c 



D. The ends of the boats. 



E. That of the trough. 



I ihould tell you, that any part of this 

 aqueduct can be repaired without dama- 

 ging the reh: of the canal, or lofing more 

 water than is contained within a fmall 

 fpace on each fide the part decayed ; for 

 fever al doors, of the fame nature as thole 

 already deicribed, are fixed in the chan- 

 nel ; and alfo trap-doors, or tubes, (if I 

 may fo call them,) at the bottom, &c. of 

 the aqueduct, through which, by drawing 

 a few plugs, the water would prefently be 

 difcharged into the Irwell, and the part 

 to be repaired, laid dry at once ; a contri- 

 vance, which is undoubtedly of vail conle- 

 quence. 



But 



