Eli Whitney invented the cotton gin while staying with Catherine Greene. He experimented over the winter and spring, arriving at a design with a spiked cylinder that pulled cotton fibers through slits while leaving seeds behind. This allowed one man and horse to do the work of 50 men with old machines. However, Whitney made little money as others copied his invention without paying. He was left virtually penniless. Whitney later moved to New Haven and developed the idea of interchangeable parts for manufacturing firearms, allowing unskilled workers to produce consistent products using machines. This "American System of Manufacture" spread across the country.

1. Eli Whitney Invents the
Cotton Gin

2. After his
conversation with
the Georgia
planters, Eli Whitney
put aside his plans
to study law and
instead tinkered
throughout the
winter and spring in
a secret workshop
provided by
Catherine Greene.

3. Before long he had
arrived at his basic
design, which had a
cylinder spiked with
wire teeth. The raw
cotton was fed onto
the cylinder and as it
rotated the teeth
passed through
narrow slits in a
piece of wood,
pulling the cotton
fibers through but
leaving the seeds
behind.

4. Within months he
had created the
cotton gin. A small
gin could be hand-
cranked; larger
versions could be
harnessed to a
horse or driven by
water power.

5. "One man and a
horse will do more
than fifty men with
the old machines,"
wrote Whitney to
his father. . . . "Tis
generally said by
those who know
anything about it,
that I shall make a
fortune by it."

6. But in the end,
Whitney made
virtually nothing
from his
invention. Others
copied his
invention and he
was left virtually
penniless.

7. Eli Whitney and
Interchangeable Parts

8. In 1804, Whitney left
the South forever,
disappointed and
disgusted. In his
words, "An invention
can be so valuable
as to be worthless to
the inventor."

9. But after settling in New Haven, Connecticut,
Whitney settled on an idea that would be as
valuable to the North as his cotton gin was to
the South.

10. In 1798, the federal government awarded Eli
Whitney a contract of $134,000 to produce
and deliver 10,000 muskets.

11. Until then, every rifle had been made by
hand from stock to barrel; but the parts of
one gun did not fit any other gun, nor did
anyone expect them to.

12. It was Whitney's
idea to use
machines that
would make all
the parts of his
rifles so nearly
identical that the
machines parts
could be
interchangeable
from one gun to
another.

13. This system of
manufacturing
would permit
an unskilled
man to turn
out a product
that would be
just as good as
one made by a
highly trained
machinist.

14. Whitney’s idea caught on all over America.
By 1850, English visitors back from America
described what they now called the “American
System of Manufacture.”