788 THE COMPLETE GRAZIER. BOOK vni. 



Ill an exhaustive report on the trials of grist mills and disintegrators 

 at Plymouth ("Journal of the Boyal Agricultural Society," vol. i., 

 3rd series, 1890, pp. 604 623), Mr. Dan. Pidgepn discusses in detail 

 the two machines just named. The " Devil " disintegrator consists of 

 a pair of grinding rings, one fixed and the other revolving, whose 

 contiguous surfaces are furnished with teeth arranged in concentric 

 circles, and diminishing in size towards the peripheries of the grinding 

 rings, but so disposed that each ring of teeth travels between similar 

 rings of teeth on the opposing annulus, as shown in fig. 359. 



" The grinding rings are placed vertically within a strong wrought- 

 iron cylindrical chamber, to which one annulus is bolted while the 

 other revolves at the rate of 800 turns per minute. Adjustment is 

 made, for fine or coarse grinding, by means of a set screw at one end of 



Fig. 360. Nicholson's Disintegrator and Cake Crusher. 



the spindle, operating against the opposing pressure of a spiral spring 

 at the other end of the shaft, which itself is driven, without counter- 

 shafting, by belt direct. All the moving parts of the mill are placed 

 between the bearings, which are very long and adequate. Only three 

 pairs of grinding discs, ' coarse/ ' medium,' and ' fine,' are employed in 

 ranging from the coarsest to the finest work. They are of cast metal, 

 having the teeth deeply chilled, and are ground together with emery for 

 the purpose of trueing up. 



"The system of grinding adopted in the 'Devil' disintegrator 

 combines the percussive action of what has been called the ' Collision ' 

 mill with a shearing action which, progressing step by step, gradually 

 reduces the material to be operated upon to any required degree of 

 fineness. Meanwhile, although nothing can escape from the mill until 



