THE MILLING OP BICE. 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. 5J 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 
