THE MILLING OF RICE. 13 



screens of the shaker frame the small quantity of finely broken rice 

 which failed of separation in the brewer's reel or resulted from a slight 

 breakage within the trumbles is removed through a No. 5| screen 

 and combined with the other brewer's rice. 



Long, revolving, cylindrical grading reels replaced in some cases 

 the earlier shaker frames. Such a reel consisted of a framework 

 divided equally into four sections, each of which was covered with a 

 wire screen. The screens, which could be replaced, were of various- 

 sized mesh, and by making substitutions the character of the sepa- 

 ration could be fairly well controlled. Beneath each section was a 

 trough to receive the rice which passed through the screen of that 

 section. The grading reels are now used only to assist the more 

 efficient cockle cylinders described in the following paragraph. 



The cockle cylinder is by far the most valuable and widely used 

 device for grading rice. It is a form of the machine extensively 

 employed in removing cockle from wheat previous to its milling, 

 and has been in use for grading rice for about 10 or 12 years. It con- 

 sists of a metal cylinder, the inside surface of which contains in- 

 dentations stamped or bored in the metal. The cylinder is set on an 

 incline and propelled from the outside, and in action revolves around 

 a supporting stationary axle, to which is also fastened an adjustable 

 curved metal apron. The apron extends nearly across the diameter 

 of the cylinder and throughout its entire length. The rice to be 

 graded is introduced on the floor of the cylinder at its upper end. 

 As the cylinder revolves, the smallest particles of rice fall into the 

 depressions, are carried upward through a part of a revolution, and 

 when above the suspended apron, they fall upon it. Since the apron 

 receives all rice particles which are carried by the surrounding cylin- 

 der above its edge, the size separation of the rice may be changed 

 at will by adjusting the position of the apron on the axle and thus 

 raising or lowering the edge of the apron. Each cylinder is desig- 

 nated according to the diameter of its depressions, which, as in the 

 case of the flat metal screens, are expressed in terms of sixty-fourths 

 of an inch. In most mills three cockle cylinders, Nos. 10, 12, and 14, 

 are set up in the same framework and are operated together, and 

 frequently two such sets are placed side by side in a double frame. 

 It is the customary practice in milling the Honduras type of rice to 

 conduct the ungraded rice from the shaker frame to the floor of 

 cockle cylinder No. 10, which takes out the smallest particles and 

 sends the remainder to cylinder No. 12 below. Broken grains of the 

 next larger size are separated on the apron of cylinder No. 12 and 

 the remainder goes down to cylinder No. 14, which performs its 

 work in a similar way. The rice from the apron in cylinder No. 10 

 is ordinarily bagged as the screenings grade of clean rice, the par- 

 ticles from the aprons of Nos. 12 and 14 are mixed and sold as the 



