Amazing photos, and an amazing collection!

Did anyone else notice the photo, labeled "1948 Gitan" (I am guessing the singular of Gitanes?), with the hand-operated rear derailleur lever?

It looked like a quick-release lever, connected by a rod that ran down the seat stay to a chain guide/grabber. Basically you just twist the lever to select the cog. Pretty interesting, and clever, in its own way....