240 Of the Management and 



large Windmil-Sails, and made propottiona- 

 ble to the Strength that is to drive them ^ fo 

 that a great Qiiantity of Water may be row*d 

 along upon a FJat, where it is not to be rais'd 

 to any Height : For this Parpofe the Spoaks 

 are made broad and fet a iittie floping, to row 

 the Water more readily 5 and they are exaftly 

 fitted to move between two Boards : But when 

 the Engine is to raife the Water any fmall 

 Height above the Level, the Spoaks are made 

 hollow like Scoops, and fet fo, as to deliver 

 the Water at the Height intended: And if 

 the Place require the Carting of it over a 

 Bank that is of any confiderabie Height, the 

 Ends of the Spoaks are to be form'd like Box- 

 es, which, as the Wheel rifes, let the Water 

 run into the Circle made hollow to receive it, 

 and a Channel being cut on the Back of the 

 Spoaks, delivers the Water as the Wheel de- 

 fcends. As this Wheel is effectual for drain- 

 ing of Lands, fo an Engine call'd the Perftan 

 Wheel, will raife a Quantity of Water fuffici- 

 ent for Overflowing of Lands that border on 

 the Banks of Rivers, where the Streams lye fo 

 low, as to be incapable of doing it. '^ This 

 *' VVheel may be made of any Size, according 

 ** to what Height you would have the Water 

 " convey 'd, and the Strength of the Stream 

 *' that gives Motion to the Engine. One Sort 

 ** of thefe Wheels is made after the manner of 

 «' an undcr-lhot Mill, with a doublb Ring, 

 ** into which are let two Pins, whereon the 



** Floats 



