ONE- VARIETY COTTON COMMUNITIES. 13 
in the gin in order that their behavior in the subsequent working of 
the gin might b a observed. 
Contrary to the general opinion of practical ginners that all of 
the left-over seed would come out with the first few bushels of the 
next " run." or at least with the seed of the first bale, it was found 
that colored seeds continued to appear, in gradually decreasing num- 
bers at the end of 5. 10. 20. and even 30 minutes, or during the whole 
period of ginning of the first bale, and that a few colored seeds still 
remained in the gin and came out with the seed of the second bale. 4 
A second report covering the same general ground, but describing 
an experiment with more recent types of gin machinery and ginhouse 
equipment, published recently shows that mixing at present is even 
more extensive than a few years ago. as a result of the use of larger 
and more numerous gin stands, with many pneumatic and screw con- 
veyors in modern gin plants. As much as 60 pounds of seed may 
remain behind in the " seed roll " of a modern 80-saw gin stand, and 
since four or more gin stands usually are employed together, the 
volume of seed mixture tends to increase rapidly. The experiment 
showed that more than 25 per cent of mixture in the seed of the first 
bale, following a different kind of cotton, is to be expected with 
modern gin equipment. Moreover, since the time of ginning a bale 
of cotton is reduced by using the larger and more numerous gin 
stands, the range of mixing is widened. Thus, in a recent experi- 
ment, with machinery that ginned a bale of cotton in 13 minutes, 
the colored seeds continued to appear not only during the ginning 
of the second bale, but a few were left for the third bale. When it 
is considered that farmers usually bring only one or two bales of 
cotton to the gin at the same time, the results of this experiment are 
practically fatal to the idea of getting any unmixed seed from a 
public gin unless special precautions are taken to clean the gin 
stands and to keep the seed from going through the conveyors. Shut- 
ting off the conveyors and sacking the seed under the gins are an 
absolute requirement. This experiment showed that contamination 
continues even to the fourth bale and beyond when seed is not sacked 
under the gin. but allowed to go through a screw conveyor. 5 
GIN-UNIT COMMUNITIES. 
Cotton is a community crop. The nature of the cotton gin. 
the machine that separates the fiber from the seed, form all the 
farmers who send their cotton to the same gin into a community 
4 Saunders, D. A., and Cardon, P. V. Custom ginning as a factor in cottonseed de- 
terioration. U. S. Dept. Agr. Bui. 288, 8 p., 5 fig. 1915. 
5 Ballard, W. W., and Doyle, C. B. Cotton-seed mixing increased by modern gin equip- 
ment. U. S. Dept. Agr. Dept. Circ. 205, 12 p.. 1 pi. 1922. 
