[ '^^1 ] 



tnd of the pafTage and the furface of the 

 water above, in the nature of a fmaller 

 well, but the mouth plugged up ; this is 

 made with defign to clear the palTage of 

 all mud or rubbiHi that might accumulate 

 in time at the bottom of the well M, by 

 drawing the plug, and letting down a 

 heavy fall of water, to drive out fuch rub- 

 bifh at the mouth O. 



The reafon why the wear was made of 

 this form, was to command a greater line 

 of extent, within a fmaller general fpace 

 than if it was a plain circle, fquare, or other 

 iimple form. The circumference is 366 

 yards, which was neceifary for the quan- 

 tity of water to be carried off; now a cir- 

 cle of that circumference could not be con- 

 tained within the outward bounds of the 

 enlarged river, and at the fame time leave 

 Ipace enough for a body of water around it. 



The lines in the plan, marked R, R, 

 denote a fubterraneous palTage, to drain 

 off all fuperfluous water at fbme houfes 

 and warchoufes at S, S, and alfo from the 

 above-mentioned one at F. At T is a 

 well and plug, as before defcribed at Q^ 

 for the fame purpofe of cleanfing the paf- 

 fage from mud and rubbidi. The water 



Vol. III. S thus 



