It never ceases to amaze me how much information is available on the internet about virtually any conceivable topic, and how quick and easy it is to find it.
People who aren't old enough to remember the world before the internet have no idea how much the world has improved in the past 20 years.
I can't even begin to list the things I know about because of the internet -- things I never would've bothered to drive to a library to look up years ago (not to mention that many of those things I wouldn't have even known how to find in a library, because I wouldn't have known what to search for).
Anyway, here's Exhibit 4,218:
Christian Chensvold's "Masculine Interiors" blog has an entry today about Harvard dorm rooms in 1899.
It reminded me of something I've wondered about for a long time, but had never bothered to look up: why so many interiors in the Victorian and Edwardian eras had pictures hung with visible strings, and why some of them were also hung slanted downward.
Apparently this was to avoid nailing into the plaster (anyone who has lived in a house with plaster walls knows how badly it chips when driving a nail, instead of making the easy, neat nail holes that occur with drywall), and presumably to also avoid marring wallpaper (when that was more common).
Evidently it was wooden, crown-type moulding, affixed at the top of the wall or close to it. Then hooks were inserted into the moulding, and pictures, mirrors, etc. could be hung from it by strings, wires or chains, which were often also decorative.
Pictures were also sometimes hung slanted downward to be more visible, especially when they were hung high on the wall (as in some of the pictures in the photo above), which I guess was more common then.
Apparently they fell out of favor around the 1920s, which coincides with the emergence of drywall.
So, there you go: picture rails.