The Story of Air Conditioning, the Barcode, and the Elevator Brake!

On this episode of  Our American Stories, Tim Harford, an economist and best selling author of  Fifty Inventions That Shaped the Modern Economy,  tells the story of these three underappreciated inventions in history. Support the show  (https://www.ouramericanstories.com/donate)See omnystudio.com/listener for privacy information.