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Another cause of plating on the top side of bales is the re-clean- 
ing of seed cotton. Certain types of gins have an overflow of soed cotton 
from the distributor. Later, this cotton is passed through the overflow 
suction pipe to the cleaning machinery, is re-cleaned, and is again pre- 
sented to the distributor. If the gin stands are still too crowded to take 
all of the cotton presented, the distributor throws the excess to the over- 
flow pile, and the cleaning process is repeated. Should the operation of 
the over-flow system cause seed cotton to pass through the cleaning equip- 
ment two or more times, a plate of different quality would probably be de- 
posited on the top of the bale. 
Ginning also affects the thickness of the plate in another way: the 
plate may not be of uniform depth. It may be thick on one end of the bale 
and thin on the other end, or it may be thick in the center of the bale and 
thin on the ends. Charles A. Bennett, senior mechanical engineer in charge 
of engineering work at the Department's experimental cotton ginning labor- 
atory at Stoneville, Miss., states that uneven distribution of fibers in a 
plate or a bale may be caused by an unequal rate of feed into the different 
gin stands, unbalanced action of brushes or air-blast nozzles that deliver 
the ginned fiber from the gin stands, or a combination of these two causes. 
To quote Mr. Bennett, "Standard construction of the lint flues in gins intro- 
duces the fiber from each gin stand to the main lint flue in such a manner 
as to give a spiralized or twisting delivery of the lint to the condenser. 
This delivery, acting like a thread on a screw, will discharge lint from 
any particular gin to a certain position on the condenser screen; conse- 
quently, the failure of all the units to deliver lint uniformly and in equal 
quantities will result in the bat being thicker at one place than another, 
and as the bale is built up, more fiber accumulates in the corresponding posi- 
tion within the press box. If one stand is not fed at the same rate as that 
for other stands, or if the doffing action of the brushes or air-blast nozzles 
produces a greater velocity of discharge from one gin stand than from another, 
it will be seen that it becomes possible for the bat to be thinned out in one 
place and thickened in others." 
Since a bale packed in this way is not of uniform density, and since 
this lack of uniformity affects the top layer of fibrous material as well 
as the underlying cotton, it is possible for a sample to be drawn at a point 
on the bale where this layer is likely to be thick and another sample to be 
drawn through a thin portion of the layer at a different position on the 
bale. This may result in differences in classifications for the same bale, 
due to actual quality differences in the samples drawn. 
In some cases, the ginner avoids placing the plate on the bottom of 
the bale by turning the press box one-fourth of the way around. As the gin- 
ning of the new bale is started, the lint from the previous bale that was 
left in the roll box is allowed to fall to the floor. After a part of the 
lint from the new bale is ginned into the press box, the lint from the pre- 
vious bale is thrown into the center of the bale, and the ginning continues. 
