Conversation so far:
Where was the first factory in North America
The first factory in North America, a cotton-spinning mill factory was built in Pawtucket, Rhode Island.
What year was the first factory in Rhode Island built
The first factory in the United States begun in Rhode Island after George Washington became President in 1790.
Who built the first facrtory in the United States in 1790
Samuel Slater, a cotton spinner's apprentice who left England the year before with the secrets of textile machinery, built a factory from memory to produce spindles of yarn.
How was the first factory in the United States built by Samuel Slater powered
The factory had 72 spindles, powered by nine children pushing foot treadles, soon replaced by water power.

Question: How many factories were built after
Self-contained rewrite: How many factories were built after the first factory in the United States