14 BULLETIN 330, U. S. DEPARTMENT OP AGRICTJLTUBE. 



second head grade, and the remainder from the floor of No. 14 con- 

 stitutes the fancy head grade. Each separated grade is conducted 

 through a wooden chute to the first floor of the mill, where it is 

 packed for the market. 



The above-described separations apply only to the Honduras type 

 of rice. The Japan type is sorted in a similar way, except that all 

 broken particles separated by the cockle cylinders are ordinarily 

 mixed and sold as Japan type screenings, thus making three grades 

 instead of four. 



Weighing and bagging machines. — All clean rice, except the brew- 

 er's rice and a small amount which is packed in cartons, is shipped 

 from the mill in closely woven burlap bags, or pockets, of 100 pounds 

 each. In many mills automatic machines for weighing the rice and 

 sewing the filled bags have been installed with satisfactory results. 



EFFECTS OF MILLING ON RICE. 



It is the purpose of modern rice milling to free the grain from 

 hulls and then to scour and grade it so as to produce a maximum 

 amount of the highly polished rice which, on account of its bright 

 luster, seems to appeal to the trade. The scouring process, to be 

 effective in removing the bran layers, is so severe that a large pro- 

 portion of the rice grains are broken, the weight of the individual 

 grains is materially decreased, and important chemical constituents 

 are removed. 



MECHANICAL EFFECT. 



METHOD OF ANALYSIS. 



A 25-gram portion of the thoroughly mixed sample was weighed 

 out for the mechanical analysis. This was shaken on a nest of two 

 flat metal screens with round holes six sixty-fourths and five sixty- 

 fourths of an inch in diameter, respectively. The particles which 

 passed through the larger holes, but remained on the screen with the 

 smaller holes, were weighed and considered as one-third grain, while 

 those which also passed through the smaller holes were classified as 

 less than one-third grain. The remainder of the sample was then 

 separated into three further sizes by hand picking with small for- 

 ceps. The whole grains were first removed and the remainder 

 divided into particles of more and particles of less than one-half 

 grains of the average size occurring in the sample under examination. 

 The weight of each of the five separations was then taken and the 

 results calculated to a percentage. The divisions, according to the 

 size of particles, are therefore (1) whole grains, (2) three-fourth 

 grains, (3) one-half grains, (4) one-third grains, (5) less than one- 

 third grains. While these designations do not describe with abso- 



