22 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE. 
SPECIAL CLEANING DEVICES. 
SPIRAL CLEANER FOR REMOVING ROUND SEEDS FROM GRAIN. 
Machines especially devised for removing round seeds from grain 
and screenings are advertised in various grain papers and catalogues 
of firms manufacturing grain-cleaning machinery. One machine used 
to separate vetch from wheat or rye consists of an upright spiral 
tube divided into several sections. The grain containing vetch is 
fed into the top and follows its course down the spiral steel tubes. 
The round seed travels more rapidly and finally gets into the outer 
tube or section, while irregularly shaped seeds and lighter matter 
move less rapidly and are discharged from the openings of the tubes 
nearer the center. Such machines require very little space, no power 
(being operated by gravity), and scarcely any watching. The 
capacity of these machines for cleaning grain thoroughly is very 
small, as only a few bushels per hour can be cleaned. They are very 
useful in separating vetch from rye or wheat where clean grain is 
desired for seeding purposes, but they have insufficient capacity for 
use in grain elevators or flour mills. 
THE COCKLE CYLINDER. 
In addition to the grain cleaners usually found in mills for pre- 
paring wheat for grinding, specially constructed machines known as 
cockle cylinders are frequently installed for the purpose of removing 
from the grain corn-cockle seed and other foreign matter and seeds 
of similar size and shape. 
Although these machines are comparatively inexpensive, a con- 
siderable quantity of wheat consisting of broken, small, and shriveled 
kernels is taken out in removing the corn cockle. This increases the 
mechanical loss that results from cleaning grain, and a portion of 
the corn-cockle seed is left in wheat after being cleaned with the 
cockle cylinder. 
MECHANICAL ANALYSES OF CORN-COCKLE SCREENINGS. 
Table XI gives the mechanical analyses of four samples of corn- 
cockle screenings secured from country mills. Sample No. 73719 
represents screenings removed in cleaning wheat with the cockle 
cylinder. Half a pound of screenings was obtained from each bushel 
of wheat cleaned. Analysis of this sample showed that but 1.3 per 
cent was corn cockle and 93.6 per cent was wheat. In the other 
three samples a relatively small percentage of the screenings con- 
sisted of corn cockle, while a high percentage was wheat. Sample 
No. 80994 represents corn-cockle screenings removed by the cleaning 
machinery in general use in country mills, and the other three samples 
are screenings removed from wheat with cockle cylinders. Such 
