Looks like it's made to pivot around that central joint...so I'd say a way to hang pipe perpendicular to another set of pipes.
Either that or for just having 2 pipes on one lineset. It doesn't look like a temporary solution. That's my 2cents.
I asked a friend that has been around for a while here in town, this was his response, not mine...
"I haven't seen one of those in a LOOOOOONG time. I believe they have not been used since the 1920's. The device with the eye bolts top and bottom is to electrically insulate the pipe ( goes in the bottom hanger ) with the lights on it from the rest of the rigging. What the picture doesn't show, is the cable hanging all that is probably the old steel plough cable. It didn't use cable clips, it used kind of a wrap around kink. Still used at Masonic Temple, Scottish Rite stage. Back in the day of EARLY resistance dimmers. The high side of the line went directly to the fixture, and the return side had the dimmer on it. The fixture always had full power to it, even if it was off."
Not sure if I agree but he is older and has been around a bit longer than I and he has worked in most of the older venues in town...
The Scottish Right stage at the Detroit Masonic is pretty amazing. Only walked through there once years ago on a very long tour organized by the Detroit Historical Society. Would love to see it again with my more knowledgeable eye.
I practically lived in an old vaudeville house growing up, and that has given me my love of the old theaters, I live not far from from some great old theaters in Detroit, just never seem to take the time to bug people for a real backstage tour.
I toured for about 15 yrs and got to go to a couple of old venues across the country....got to see some great places with amazing history, even a salt water dimmer setup, they used only for the house lights if I remember correctly, kept it running to keep there historical statues.
I also would like to see some of these places now that I know a little more, and appreciate more of the history...
I shall keep that in mind, funny how you forget that someone you know can possess such great amounts of knowledge....and never really think about it, I seem to only remember the silly little stuff...
one thing I like about controlbooth, if you have question or a problem, someone here has had the same issue and come up with a fix or a workaround, and willing to share...
Sean...
And I like old theaters with good ghosts stories...
Here is a link about early home wiring which was posted by Mike Sokol as above. http://www.rexophone.com/?p=1175
Interesting that the remote light switch was considered the most expensive option and not used often. The previous light source (candle, kerosene lamp, gas light) had to be illuminated individually so why not do the same with that new-fangled Electricical thing.