( we) 
much, that if the flood continues, it fhall carry all away 
together. 
For preventing of this mifchief, there are two wavs; r. 
Grates at each end of the bank, planted upon the level that is 
to be the higheft of the water. 2. Channels of diver- 
fion, which being taken fo high in the current as may lead the 
water upon the fide of either hill above the bank, you have 
the power to turn out all the water when you pleafe, fo that 
none fhall come upon the bank. 
1. As to grates, the way of them is well known; however 
obferve, that if they be made of wood, the banks muft be fet 
diagonally, like window-bars ; for fo rubbifh ftops leaft againft 
them, and the water paffeth freely. And in regard you can- 
not allow any great diftance between them for keeping in the 
fith, you muft-help out the room by extending the grate from 
each fide of the cut in the bank where the water is to. vent, 
fome confiderable {pace from the bank, and there to meet in 
1 point, forming a triangle upon the bank. Here are many 
more {lits for the water to vent at, than if the grate lay flat 
upon the bank, covering the paflage only. Andif need be, 
there may be doors to flide up and down, made in the grate, 
to let the water pafs more freely ; but this endangereth lofing 
the fifth. If you will afford iron for thefe grates, you need 
only cover the paflage of the bank; for the bars need not 
be fo thick, but there will be fpace enough for the water to 
vent at. 
2. The channels for diverting the water are very ufeful in 
this and many other refpeds; for they give you a perfe& 
command 
