Chap. 3.] . Water IVheels. 471 



float-boards, they Ihould be furnifhed with concave 

 or hollow ones refembling buckets, whenever we 

 can have a fall of more than four feet, and efpecially 

 where there is not the neceflary quantity of water to 

 turn a mill with wheels, furnimsd with plain > float- 

 boards. 



M. Deparcieux, in the Memoirs of the French 

 Academy of Sciences *, has proved, that the flower 

 wheels with buckets move, the more will be their 

 effect with an equal expence of water. He made a 

 fmall wheel of twenty inches diameter, the circum- 

 ference of which was furniflied with forty-eight buck- 

 ets. Upon the axis of this wheel were placed four 

 cylinders of different fizes ; the leaft was one inch 

 in diameter, the next two inches, the third three 

 inches, and the fourth was four inches in diameter. 

 Thefe cylinders were different axes, about which a 

 cord, which elevated a weight by means of a re- 

 turning pully placed above the machine, wrapped it- 

 felf. The axis of the wheel was fupported at each 

 end by two rollers eafily put in motion; this was to 

 diminifh the friction. To the fore part of the wheel, 

 and a little higher than its axis, was attached a fmall 

 fhelf, upon which was placed a veflel with a hole 

 pierced in it on that fide towards the wheel, which was 

 rilled, with water. Above this veflel was placed a 

 large bottle full of water inverted, and the neck of it 

 was plunged a few lines in the water of the veflel, in 

 order that the bottle Ihould only empty itfelf in pro- 

 portion as the water in the veflel ran through the 

 aperture. The water in flowing fell into a channel 

 which carried it into the buckets of the wheel. By 

 this means he made fure of employing, at each expe^. 

 always the fame quantity of" water. 



* Fpr the year 1754, page 603 and 671. 



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