Back in Colonial times, Americans raised most of the food they ate and made most of the clothes they wore . They spun their own yarn, wove their own cloth, and stitched their own garments. They dipped candles and built tables and chairs. When wealthy colonists wanted fancy dishes, fine cloth, or elegant furniture, they sent to England for them. Manufactured goods were made in England; raw materials came from the colonies. Then, during the American Revolution, that system stopped. Suddenly there was no place to send raw materials and no supply of fine goods. The colonists had to find new markets for their lumber, tobacco, cotton, and other raw materials. Soon their sailing ships were calling in ports from Spain to India.

After the war, the new United States began trading with England again. At the same time, America was growing and changing. Our democracy was producing a strong middle class. It wasn't only the very rich who wanted to buy manufactured goods. Ordinary people wanted them too. And something was happening in England that would make that possible. It was another revolution—an industrial revolution (although no one called it that for a while). It was a way of organizing work, based on new ideas in science and technology and business. Things once made at home—like cotton and cloth—were being made faster, and often better, in factories . And it all began in England .

Machinery made factories possible. But the English had no intention of sharing their technology. They planned to keep the Industrial Revolution for themselves. Americans wanted those machines. Some people offered a big reward to anyone who could build a cotton-spinning machine in the United States . In England, no one who worked in a cotton factory was allowed to leave the country. A cotton spinner's apprentice named Sam Slater was one of the many who signed binding agreements with their employers called indentures. Sam's read this way: "This indenture witnesseth that Samuel Slater doth put himself apprentice to Jedediah Strutt for the term of six years and a half. During which time he faithfully shall serve his secrets, and keep his loyal commands."

Young Sam Slater had a remarkable memory. He memorized the way the spinning machines in Jedediah Strutt's cotton factory were built and operated. Then, in 1784, he ran off to London, pretended to be a farm worker, and sailed for America. He had the key to the Industrial Revolution with him—in his head. In 1790, Sam built a small cotton-spinning factory next to a waterfall on the Blackstone River at Pawtucket, Rhode Island . It was the first true American factory. Waterpower turned the machines that spun cotton fibers into yarn. Soon there were spinning mills—and, later, weaving machines—beside many New England streams .

Now that factories could turn cotton into yarn quickly and easily, there was a great demand for raw cotton. Anyone who could grow cotton would make a lot of money. But the cotton that would grow in most of America—short-staple cotton—has lots of dark seeds, and those seeds stick to the cotton balls. It took a worker all day to remove the seeds from just one pound of cotton . So cotton was very expensive.

Eli Whitney , a New Englander with an inventive mind, had just graduated from Yale when he arrived in Savannah, Georgia, to take a job as a teacher. He heard about the cotton problem. He said, "If a machine could be invented that would clean cotton, it would be a great thing." In 1793, he came up with a simple machine that removed seeds from cotton. He called it a "cotton engine"—the name was soon shortened to "cotton gin." A worker with a cotton gin could clean fifty pounds in one day—instead of just one pound.

Eli Whitney's cotton gin did a lot more than just supply cotton to northern mills; it transformed the whole economy of the South. It made the cotton pickers—who were slaves—essential. Slavery, which had been dying out, again became important economically. Whitney never expected that.