COTTON 219 
vent the seed from passing through with the lint. 
On the lower side of the cylinder set with saws is 
a revolving brush which takes off the lint as it comes 
through the saw teeth, and a blast from a revolving 
fan carries it back through a flue into a lint room 
in the rear of the machine. This is the essential 
principle of the Whitney gin as well as of all suc- 
ceeding ones that have yet been made. 
PRESENT DAY GINNING 
There are two kinds of gins used at the present 
time: roller and saw. ‘The former, old long before 
Whitney’s saw gin was invented, is used for ginning 
Sea Island cotton, while the saw gin is always used 
for the upland varieties. Seed of Sea Island cot- 
ton, it must be remembered, are loose in the lint, 
smooth and clean,—as contrasted with upland 
seed to which the lint is as firmly attached as 
barnacles to a log. Hence the need of two forms 
of ginning. 
The cotton gin is by no means perfect yet: it 
leaves too much dirt and trash in the lint during 
the process of separation from the seed. | Whether 
perfection in this direction is at all possible, the 
future only can say; but at present the waste in 
form of dirt, weak fibers, seed and leaf is a mat- 
ter of considerable consequence. The gins now 
used also cut the lint badly, thereby seriously dam- 
aging it for manufacturing purposes. With the 
coming of improvements, cotton ginning has be- 
come an industry, almost separate and distinct 
in itself. 
Not many years ago nearly every plantation had 
its own gin: but there were many items of expense 
which made the small gin too expensive. It was 
