Charles River Museum's Tesla exhibit asks: Who owns an idea?

State of play: The Waltham museum opened the exhibition on Friday, which marked Tesla's 170th birthday.

• It features never-before-published correspondence between the watch company and Tesla, including a dispute over profits from speedometers designed by Tesla and made by the company.

What they're saying: The exhibition explores broader questions about the "why patents are so central to the innovation economy," says Steve Guerriero, the museum's director of education.

• "It is so central to our framers that they put it in the Constitution."

Zoom out: Massachusetts has been home to some of the biggest patent disputes in the nation's history, from spats over sewing machines and guns to present-day battles over gene therapy and other life-saving medical treatments.

Flashback: The Waltham Watch Company started making the speedometer patented by Tesla in the early 1920s as luxury parts for Cadillacs and Rolls-Royces.

• The company had also bought a patent for a speedometer filed in 1915 by Stead Asquith, a West Coast inventor — not to work with him, but to prevent him from suing once Waltham started making Tesla's speedometers, Guerriero tells Axios.

Yes, but: Specialty speedometers like Waltham's fell out of favor by the late 1920s, and Ford's own speedometer was selling for far less.

• That's when the watch company started asking Tesla to take a smaller cut of the profits, Guerriero says.
• Tesla, who had lost millions after giving up royalties from his AC technology patents to Westinghouse Electric, refused to budge.

What's next: The exhibition runs until at least next spring.