Circa earum frontes adfiguntur pinnae, quae, cum percutiuntur ab impetu fluminis, cogunt progredientes versari rotam, et ita modiolis haurientis et in summum referentes sine operarum calcatura ipsius fluminis inpulsu versatae praestant, quod opus est ad usum.
Round the outside, paddles are fixed, and these, when they are acted on by the current of the river, move on and cause the wheel to turn. In this fashion they draw up the water in buckets and carry it to the top without workmen to tread the wheel. Hence, being turned by the force of the river only, they supply what is required.
final_alignments\Vitruvius_Architecture_Book_10.json