In 1800 most Americans grew most of what they ate and made much of what they used, and moving goods inland was slow and costly. By the 1840s farm families sold crops to distant cities and bought cloth, tools and clocks made in factories. Historians call this change the market revolution. It grew from the roads and canals of the American System and from new machines.
Key idea
Transportation: steamboats (Robert Fulton's, 1807), the Erie Canal (opened 1825, linking the Hudson River to Lake Erie), and railroads (from about 1830). The North: textile mills, such as those at Lowell, Massachusetts, staffed at first by young women from farm families. The South: the cotton gin (1793) and world demand for cotton spread cotton farming, and slavery, across the Deep South.
Why it works
Cheap transport is the key. Before the Erie Canal, moving a ton of freight from Buffalo to New York City by wagon cost about \$100. By canal barge it cost about \$10, so western farmers could sell in the East and abroad, and New York City became the country's largest port. When goods move cheaply, each region does what it does best and trades for the rest: grain from the Northwest, cloth from New England, cotton from the South.
Worked example: Why the gin spread slavery
Eli Whitney's cotton gin let one worker clean about 50 pounds of cotton a day instead of about one pound by hand. Why did that make slavery grow instead of shrink?
- Cleaning the seeds out of short-staple cotton had been the slow step. The gin removed that bottleneck.
- Short-staple cotton grows across the inland South, so cotton suddenly paid almost everywhere there.
- Planting and picking were still done by hand, so planters wanted more workers, and they used enslaved people.
- The enslaved population grew from about 700,000 in 1790 to about 4 million in 1860, and many were forced to move from the Upper South to new cotton lands.
Answer: It saved labor in one step but made cotton profitable everywhere, so demand for enslaved field workers soared.
Common mistake
The cotton gin did not reduce slavery by saving labor. It made short-staple cotton profitable, so cotton planting and the number of enslaved people both grew fast. Check: a machine that saves labor in one step can raise the demand for labor in the others.
The market revolution tied the North and the South together: Northern mills and banks depended on Southern cotton, and Southern planters sold to British and New England mills. Historians debate how much of the North's growth came from cotton, but the links were close.