Does anybody know what this apparatus is for?

[thatgameguy]

Hi folks,

I work as a Lab Technician in a High School and we've been sorting out a lot of the school's old physics equipment. I found this unknown piece of apparatus with the Wheatstone Bridges:

I assume it works in a similar way to a Wheatstone Bridge but I just can't quite work out what to do with it. Does anybody recognise what it is or know what to do with it? I apologise for the poor quality of the photos!

 

[amk_dbz]

I think it is a Meter bridge. Search Meter bridge on google for more Information.
In brief, it is used to set up Wheatstone network and to find out unknown resistance.

 

[Studiot]

I think it is a slide wire potentiometer.