70 OF MILLS. 



tity will be more or less, according as the shoe is 

 more or less let down ; for the hopper is open at 

 bottom, and there is a hole in the bottom of the 

 shoe, not directly under the bottom of the hopper, 

 but nearer to the lowest end of the shoe, over the 

 middle eye of the mill-stone. 



There is a square hole in the top of the spindle, 

 in which is put the feeder E (Fig. 13.) ; this feeder, 

 as the spindle turns rounds, jogs the shoes three 

 times in each revolution, and so causes the corn to 

 run constantly down from the hopper through the 

 shoe, into the eye of the mill-stone, where it falls 

 upon the top of the rynd ; and is, by the motion 

 of the rynd, and the leather under it thrown below 

 the upper stone, and ground between it and the 

 lower one. The violent motion of the stone creates 

 a centrifugal force in the corn going round with 

 it ; by which means it gets farther and farther 

 from the centre, as in a spiral, in every revolution, 

 until it be quite thrown out ; and being then 

 ground, it falls through a spout, called the mill- 

 eye, into a trough placed to receive it. 



When the mill is fed too fast, the corn bears up 

 the stone, and is ground too coarse; and, besides, 

 it clogs the mill, so as to make it go too slow. 

 When the mill is too slowly fed, it goes too fast, 

 and the stones, by their attrition, are apt to strike 

 fire. Both which inconveniences are avoided by 

 turning the pin S backward or forward, which 

 draws up or lets down the shoe, and thus regu- 

 lates the feeding, as the miller sees convenient. 



The heavier the running mill-stone is, and the 

 greater the quantity of water that falls upon the 

 wheel, the faster will the mill bear to be fed ; and 

 consequently it will grind the more. And, on the 

 contrary, the lighter the stone, and the less the 





