And then the network’s racial barriers reasserted themselves, and the deal collapsed.

The fourth barrier was intellectual property protection itself.

While the patent system was formally open to all, the enforcement of patent rights required access to the legal system, which was expensive and which — like other American institutions — was not always equally available to people of all races.

Black inventors who had their inventions stolen or copied faced the additional barrier of navigating a legal system that was not always disposed to take their claims seriously.

Granville Woods’s experience with Edison illustrates this.