6 BULLETIN 1319, U. S. DEPARTMENT OP AGRICULTURE 
when a greater number of picker rolls are used or if they move at 
a greater speed. It is not desirable to pull the locks apart and sepa- 
rate the individual seeds, since this results in more twisting of the 
fibers, or the fibers may be rolled so closely around the seeds that they 
pass through the grids with the ginned seed. (PL VI.) 
DISTRIBUTING THE SEED COTTON TO THE GIN STAND 
_ For long-staple cotton the pneumatic-elevator method of distribu- 
tion to feeders is preferable to the belt-conveyor system, having 
less tendency to roll and tangle the fiber. Of course, the worst 
tangling and rolling occur when the overflow cotton is resucked, so 
that it passes over the belt a second time. 
FEEDING THE SEED COTTON TO THE ROLLER 
Feeding by hand gives the best sample of ginned cotton but is 
more expensive, so most of the gin plants use mechanical feeders. 
With the mechanical feeders the cotton falls from the cleaner 
feeder into a box on the gin stand. This box may be stationary and 
may have a sloping bottom so that the cotton rolls forward, or 
the box may be agitated to carry the cotton forward to the gin 
roller. In such feeders the box has a flat perforated bottom through 
which dirt and small leaf trash may fall. (PL V, fig. 2.) The 
seed cotton is taken from the box by a broad endless belt of canvas 
having numerous wire spikes that carry small masses of seed cotton 
and deposit them in front of the gin roller. These feeders tear more 
of the locks apart and also are likely to keep too much unginned 
cotton on the seed grid. This, in turn, prevents the ginned seed from 
falling through the grids promptly, and the seeds tend to accumulate 
in front of the roller, blocking the unginned cotton. Though these 
feeding devices are the best available at the present time, further 
improvement should be sought to give increased efficiency in ginning. 
CONSTRUCTION AND CARE OF THE GIN ROLLERS 
The gin rollers are wooden cylinders with a covering of walrus 
hide in the form of strips about three-fourths inch wide laid on 
spirally and held in place by glue and wooden pegs driven through 
the hide into the wooden core. To avoid the expense of walrus 
hide different kinds of leather and several other substitutes have 
been suggested and tried, but none with complete success. Some 
combinations of walrus hide with rubber packing or friction paper 
are practical and even superior in some respects to walrus hide alone, 
as well as more economical. The packing or paper is put between 
the strips of walrus hide and should never be thicker than a quarter 
of an inch, as its chief function is to keep the fixed knife from 
wearing the leather too fast. The paper or packing is harder than 
the leather and takes most of the pressure of the knife, leaving just 
enough pressure on the leather to pull the cotton over the gin roller. 
Also the packing or paper, having a uniform consistency, will wear 
evenly and keep the roller true, so that repairs are not required so 
frequently. If the leather wears in holes the paper will lap over and 
fill them, thus obviating the clanger of cracking seed. Friction 
paper is better than rubber packing but more difficult to put on 
the roller. 
