Firestone, Ford and Edison were friends and partners. In their pursuit to find a natural source of rubber (prices of rubber had soared at the time). Ford, Firestone, and Edison equally funded a laboratory on the property.
The three were also great camping buddies and camped in suit and tie.
This laboratory is where Edison conducted his last major experiments.
On a personal note:
This was by far my favorite part of the Edison Ford Estate. Upon entering the lab I realized that I was in the workspace of possibly the greatest man to ever live. It was dark and warm inside. A picture of the three (Edison, Ford, Firestone) is placed high above the heads of any who enter the lab. I felt that to be a very appropriate place. The lab possessed a creepy feeling. It was almost as if there were ghosts. All of the devices in the lab, all of the test tubes, everything in that room had a sense of importance, and change, progress, worth.
Bib. All info was gathered from the Edison Ford Estate and the Fort Myers Chamber of Commerce