The evolution of mobile devices from the first commercially available DynaTAC to the smartphones of today.
Each tube could carry between 400 and 600 letters and traveled at 30-35 miles per hour. In its full glory, the pneumatic tubes covered a 27-mile route, connecting 23 post offices…. 95,000 letters were moved daily [and] it took 4 minutes to get from the General Post Office to Grand Central using a transverse tube that cut across Manhattan.
- Elon Musk, SXSW keynote (via Wired.com)
Commuter train in Bohn’s ‘Visions of the Future’ Ads, 1940s
America of the Future, c. 1910s-30s.