OF WATER-MILLS. 



89 



that means, will wear all the parts of the cogs and 

 rounds which work upon one another equally, and to 

 equal distances from one another in a little time ; and 

 so make a true uniform motion throughout the whole 

 work. Thus, in the above water-mill, the trundle has 

 10 staves, and the wheel 61 cogs. 



Sometimes, where there is a sufficient quantity of 





water, the cog-wheel A A turns a large trundle B B } 

 on whose axis C is fixed the horizontal wheel D, with 

 cogs all around its edge, turning two trundles E and F 

 at the same time ; whose axes or spindles G and H turn 

 two millstones / and K, upon the fixed stones L and 

 M. And when there is not work for them both, either 

 may be made to lie quiet, by taking out one of the 

 staves of its trundle, and turning the vacant place to- 

 wards the cog-wheel D. And there may be a wheel 

 fixed on the upper end of the great upright axle C for 

 turning a couple of boulting jaills ; and other work for 

 .drawing up the sacks, fanning and cleaning the corn* 

 sharpening of tools, &c. 



If, instead of the cog-wheel A A and trundle B B, 



'11 



horizontal levers be fixed into the axle C, below the"" 

 wheel D ; then, horses may be put to these levers for 

 turning the mill : which is often done where water can- 

 not be had for that purpose. 



The working parts of a wind-mill differ very little A wind- 

 from those of a water-mill ; ? nly the former is turned miu " 



