177 



engine, which was erected near the West'* 

 India Docks, at Poplar, raised, I sup* 

 pose, more water than any of the above-^ 

 mentioned; and yet, as far as I could 

 judge from the appearance of the stream 

 that flowed from it, it did not afford 

 water enough fully to float three acres at 

 a time. Denon tells us, that in Eg}^pt 

 wheels, with pots aflixed round them, are 

 worked by oxen, to raise water for irriga* 

 tion ; but he says that windmills would 

 answer the purpose much better. Mr, 

 Tatham mentions the Persian wheel, 

 which is worked by the stream from 

 which it raises the water, as having been 

 used in irrigation in America; but he 

 says the German lifting-wheel has equal 

 power with the Persian, and is preferable 

 to it for simplicity and cheapness. Mr. 

 Tatham is bold enough to assert that, 

 by means pf machinery, water might be 



raised 



