Users of early elevators were responsible for opening and closing the doors manually, and sometimes the doors were left open, creating a hazardous situation with the shaft exposed. As Andreas Bernard writes in his 2006 history of elevators:
. . .in the 1880s, manually operated or hinged doors. . .on each floor still frequently misled careless passengers wishing to enter the cab into opening them and falling into the shaft. (Andreas Barnard, Lifted: A Cultural History of the Elevator, p.31)
Duluthian Alexander Miles helped solve this problem by inventing an improved mechanism for opening and closing elevator doors when the car arrives at or departs the floor. This is just one accomplishment of this successful and creative businessman who lived in Duluth in the late 1800s and was thought at the time to be the wealthiest black man in the Midwest.