The reason why Francis Lowell's partners might have decided to build a factory was because the river in the town could power the factory.
The early illustration described in the question, shows a river flowing through the town of Lowell.
This river could have several benefits for a factory such as powering it and allowing for transportation of produced goods to other areas thereby reducing transportation costs.
Find out more on the town of Lowell at https://brainly.com/question/15349195.
