Billing itself modestly as “one of the largest” collections of antique bank locks in existence, the John M. Mossman Lock Collection has more than 370 lock mechanisms on display.

Behind glass on the second floor of the General Society of Mechanics and Tradesmen, these somewhat mundane-looking pieces of technology hail from a time — most are of 19th century vintage — when lock mechanisms relied on unbelievably ornate workmanship, similar to those required for timepieces. Some of the locks even relied on time mechanisms to be opened, and were openable only at a particular hour of the day, or sometimes, the year.

The locks also boast impressive hand-tooled details, many of which would only decorate the seldom-seen interior of the locks. But don’t be fooled by their baroque beauty. In their day, as the General Society notes, “nearly every lock has protected millions in money and securities.”

The collection was given to this venerable organization by John M. Mossman himself, who in 1928 wrote an accompanying history entitled “The Lure of the Lock,” available from the Society. The Collection’s current curator John Erroll, and his son David, are the authors of a beautiful but little-known 2006 coffee-table book on the collection entitled American Genius, and proprietors of time-lock.com, where they further explore the obscure history of this important invention.