The invention of the cotton gin and revival of slavery were most likely the cause of the trend shown on the map. The map shows a significant increase in the production of cotton from 1800 until 1860. The map also shows how there was an increase in the extent of land used for cotton production, spreading mostly across the south-eastern part of the United States.
The cotton gin is a machine that separates cotton fibers from their seeds which allows higher productivity than when it is done manually. Eli Whitney, an American inventor, created the cotton gin in 1973. The implementation of this invention in the 1800's would explain the increase in cotton productivity. On the other hand, this invention also signified that the demand for cotton workers increased and therefore led to the growth of slavery.
