Mystery object

[ppppenguin]

I wonder if we're being fooled by the 90 markings. It doesn't have to be angle; it could be voltage or current. So a centre zero ammeter might be plausible though 90A is far too much for that wire. 90mA? Or 90V if there's suitable resistance? If the coil still has continuity then easy enough to apply a voltage and see. The wires are of an old fashioned type,probably no later than 1930s, as is the little connector on the end of one of them.

If it's fairly sensitive it could be a crude galvanometer for measuring bridge balance etc.