Hello, Can anyone tell me what the hinged bar on my rolling rule is?

The what ? from where.....doing what ??

 

More photos

 

nm

 

so paper can slide in between the two wood pieces........? maybe?

 

Looks a little like a map/chart roller. How long is it?

 

I know it's a rule which was used for drawing lines with ink and is round to prevent blotting .It's
12 inches long.

I'm told the bar was to prevent the clerk's cuffs from getting ink on. I just want to know if this is correct. Thanks for replies so far!

 

I don't think that is correct.....
I see many rolling rules, ( rulers) out there , in their lovely boxes...but have yet to find one like yours with a curved wood attachment.
So , I can't confirm that what you were told has any credibility .

 

Thanks for your help anyway!

 

Does one come off to slide in a document? Catching a hold on the crescent end and rolled into round top? Maybe there is a rare doc in there?

 

You say it is "hinged". How does the second part move - does it just rotate around the solid round part? Are there brass fittings on both ends, or just one? If only one end, it seems it might be designed to slip something between the two parts, roll it up, and then slip it back off the open end. Like a chart roller, as @Hollyblue suggested, but for something smaller than a typical map.

Alternatively, maybe the second part is just there to keep it from rolling off the clerk's slanted desk.