Pneumatic Tube Vestige, New Haven

shows the truncated tube for a long-disused pheumatic tube system

Update, 20 Feb 2019: I’m fascinated by pneumatic tubes, have been ever since as a tot I saw their magic at the bank’s drive-through teller. You can read up a little on this library’s use of them from an article published when the library was brand new (JSTOR access required).