BOOK VIII. 



is turned by water-power, is made in the following way. An axle is rounded 

 to compass measure, or is made angular, and its iron pinions turn in iron 

 sockets which are held in beams. The axle is turned by a water-wheel, the 

 buckets of which are fixed to the rim and are struck by the force of a stream. 



A AXLE. B WATER-WHEEL. C TOOTHED DRUM. D DRUM MADE OF RUNDLES. 

 E IRON AXLE. F MILLSTONE. G HOPPER. H ROUND WOODEN PLATE. 



I TROUGH. 



Into the axle is mortised a toothed drum, whose teeth are fixed in the side 

 of the rim. These teeth turn a second drum of rundles, which are made of 

 very hard material. This drum surrounds an iron axle which has a pinion 

 at the bottom and revolves in an iron cup in a timber. At the top of the 

 iron axle is an iron tongue, dove-tailed into the millstone, and so when the 

 teeth of the one drum turn the rundles of the other, the millstone is made to 

 turn round. An overhanging machine supplies it with ore through a hopper, 

 and the ore, being ground to powder, is discharged from a round wooden plate 

 into a trough and flowing away through it accumulates on the floor ; 

 from there the ore is carried away and reserved for washing. Since this 



