7'2 OF ^ULLS. 



the more forcibly is the corn wedged in between 

 them. 



In order to cut and grind the corn, both the 

 upper and under mill-stones have channels or fur- 

 rows cut into them, proceeding obliquely from 

 the centre to the circumference. These furrows 

 are cut perpendicularly on one side and obliquely 

 on the other, which gives each furrow a sharp 

 edge; and in the two stones they come, as it were, 

 against one another, like the edges of a pair of 

 scissors, and so cut the corn, to make it grind the 

 easier, when it falls upon the places between the 

 furrows. These are cut the same way in both 

 stones, when they lie upon their backs, which makes 

 them run crossways to each other when the upper 

 stone is inverted by turning its furrowed surface 

 towards that of the lower; for, if the furrows of 

 both stones lay the same way, a great deal of the 

 corn would be driven onward in the lower furrows, 

 and so come out from between the stones, without 

 being; either cut or bruised. 



The grinding surface of the under stone is a 

 little convex from the edge to the centre, and that 

 of the upper stone a little concave; so that they 

 are farthest from one another in the middle, and 

 approach gradually nearer towards the edges. By 

 this means the corn, at its first entrance between 

 the stones, is only bruised; but as it goes farther 

 on towards the circumference or edge, it is cut 

 smaller and smaller, and at last finely ground, just 

 before it comes out from between them. 



When the furrows become blunt and shallow by 

 wearing, the running stone must be taken up, and 

 both stones new drest with a chisel and hammer; 

 and every time the stone is taken up, there must be 

 some tallow put round the spindle upon the bush, 



