Can you ID this turn of century tool I found?

[relicmeister]

I found this interesting tool at a Victorian era homesite and I've never figured out what it's for.
The graduations are not English but the lower might be metric. There are indents at each major increment. Also the straight edge has knurling or straight teeth.
No maker mark anywhere. Any ideas ? Thanks

 

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[nsdq]

Arm for a scale ?

 

[jewelerguy]

Arm for a scale ?

I agree

 

[BuckleBoy]

Yes, definitely an arm from a scale.

 

[ToastedWheatie]

Yep. Looks like the slide for a single beam balance. Like the doctor's office.

 

[BosnMate]

Ditto to all of the above.

 

[A2coins]

All Aboard!!!!!!! me too